JP2010242231A - Coated paper - Google Patents

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JP2010242231A
JP2010242231A JP2009088992A JP2009088992A JP2010242231A JP 2010242231 A JP2010242231 A JP 2010242231A JP 2009088992 A JP2009088992 A JP 2009088992A JP 2009088992 A JP2009088992 A JP 2009088992A JP 2010242231 A JP2010242231 A JP 2010242231A
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pigment
paper
coating layer
coated paper
mass
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Shinichi Takechi
伸一 武智
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Daio Paper Corp
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Daio Paper Corp
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Abstract

<P>PROBLEM TO BE SOLVED: To provide coated paper having high whiteness, white paper gloss, and surface strength, and excellent blister resistance. <P>SOLUTION: The coated paper is obtained by providing base paper with an undercoating layer essentially consisting of a starch or a starch derivative as a main component in a coated amount per side of 0.5-1.0 g/m<SP>2</SP>. The undercoating layer is provided with a top coating layer essentially consisting of pigment and an adhesive as main components. The pigment has a particle diameter distribution having the maximum value in the range of &ge;0.1 &mu;m and &lt;0.8 &mu;m in particle diameter distribution totalized for each 0.1 &mu;m. Preferably, the pigment has a particle diameter distribution having the maximum in the range of &ge;0.8 &mu;m and &lt;2.0 &mu;m. <P>COPYRIGHT: (C)2011,JPO&amp;INPIT

Description

本発明は塗工紙に関する。さらに詳しくは、澱粉又は澱粉誘導体を主成分とする下塗り塗工層を、片面あたり0.5〜1.0g/m設けた後、粒子径の分布において0.1μm以上0.8μm未満の顔料及び接着剤を主成分とする上塗り塗工層を設けた塗工紙に関する。 The present invention relates to coated paper. More specifically, after an undercoat coating layer mainly composed of starch or starch derivative is provided at 0.5 to 1.0 g / m 2 per side, a pigment having a particle size distribution of 0.1 μm or more and less than 0.8 μm And a coated paper provided with a top coat layer mainly composed of an adhesive.

近年、環境問題の観点から、より軽量の塗工紙に対する要求がある。特に塗工量が両面で15g/m(片面あたり7.5g/m)を超過するほど多く、白色度、白紙光沢度、表面強度に優れたA3コート紙から、塗工量が両面で15g/m(片面あたり7.5g/m)以下と少なく、A3コート紙と比べて白色度、白紙光沢度、表面強度に劣る微塗工紙への置き換えが進んでいる。置き換えにより見栄えが低下しないよう、A3コート紙と同程度の白色度、白紙光沢度、表面強度を備える微塗工紙に対する要求がある。 In recent years, there has been a demand for lighter coated paper from the viewpoint of environmental problems. In particular, the coating amount is so large that the coating amount exceeds 15 g / m 2 (7.5 g / m 2 per side) on both sides, and the coating amount is on both sides from A3 coated paper excellent in whiteness, white paper glossiness, and surface strength. It is less than 15 g / m 2 (7.5 g / m 2 per side) and is being replaced with finely coated paper that is inferior in whiteness, white paper gloss, and surface strength compared to A3 coated paper. There is a demand for finely coated paper having the same whiteness, white paper glossiness, and surface strength as A3 coated paper so that the appearance does not deteriorate by replacement.

一般的な印刷用塗工紙に用いる顔料は、コストメリットの観点から炭酸カルシウム及びクレーが多く用いられており、白色度は高いが白紙光沢が低い炭酸カルシウムと、白色度は低いが白紙光沢が高いクレーを、塗工紙の要求品質に応じて配合している。   Calcium carbonate and clay are often used as pigments for general coated paper for printing from the viewpoint of cost merit. Calcium carbonate has high whiteness but low white paper gloss, and low whiteness but white paper gloss. High clay is blended according to the required quality of coated paper.

A3コート紙は微塗工紙と比べて、塗工量が多く白紙光沢度が向上しやすいため、クレーが少なくて済み、炭酸カルシウムが比較的多く配合されるので、結果白色度に優れる。しかしながら微塗工紙は塗工量がA3コート紙と比べて少ないため、塗工紙表面が平坦化されにくく、炭酸カルシウム及びクレーの配合量がA3コート紙と同程度では、白紙光沢度に劣る問題がある。クレーを増配すると白紙光沢度は向上するが、一方で白色度が低下する問題がある。   Compared with finely coated paper, A3 coated paper has a large coating amount and easily improves the glossiness of the white paper, so that less clay is required and a relatively large amount of calcium carbonate is blended, resulting in excellent whiteness. However, since the coated amount of the fine coated paper is smaller than that of the A3 coated paper, the coated paper surface is difficult to be flattened, and when the blending amount of calcium carbonate and clay is the same as that of the A3 coated paper, the glossiness of the white paper is inferior. There's a problem. When the clay is increased, the glossiness of the white paper is improved, but the whiteness is lowered.

クレーを高配合しながら白色度を向上させる方法としては、蛍光染料を添加する技術が開示されているが、退色性に劣る問題がある(特許文献1を参照)。   As a method for improving whiteness while highly blending clay, a technique of adding a fluorescent dye is disclosed, but there is a problem inferior in fading (see Patent Document 1).

炭酸カルシウムを配合しても高い白紙光沢度を得る方法としては、より粒子径の小さい微粒炭酸カルシウムを用いる技術が開示されており、白色度及び白紙光沢度に優れる塗工紙が得られる(特許文献2を参照)。しかしながら粒子径の小さい顔料を基紙に直接塗工すると、顔料が基紙に沈み込み易く、十分な白紙光沢度が得られないだけでなく、表面強度にも劣る問題がある。目止め層として顔料塗工層を下塗り塗工することで、十分な白紙光沢度は得られるが、一方で顔料2層塗工層となるため塗工量が多くなり、透気性が低くなるためオフセット印刷の乾燥工程において基紙中の水分が水蒸気となることに起因するブリスター(火ぶくれ)欠陥が発生しやすくなる問題がある。   As a method for obtaining high white paper gloss even when calcium carbonate is added, a technique using fine calcium carbonate having a smaller particle diameter is disclosed, and a coated paper having excellent whiteness and white paper gloss can be obtained (patent) Reference 2). However, when a pigment having a small particle diameter is directly applied to the base paper, the pigment is liable to sink into the base paper, and not only a sufficient white paper glossiness cannot be obtained, but also the surface strength is inferior. By coating the pigment coating layer as a sealing layer, sufficient white paper glossiness can be obtained, but on the other hand, since it becomes a pigment two-layer coating layer, the coating amount increases and the air permeability decreases. In the drying process of offset printing, there is a problem that a blister (blur) defect is likely to occur due to water in the base paper becoming water vapor.

また、高い白紙光沢が得られる顔料としてプラスチックピグメントを使用する技術も開示されているが、塗料の流動性が悪化して塗工ムラが発生し易く、特に微塗工紙のような低塗工量の塗工紙では塗工ムラが目立ち、見栄えが低下する(特許文献3を参照)。   In addition, a technique using a plastic pigment as a pigment capable of obtaining high white paper gloss is disclosed, but the fluidity of the paint deteriorates and coating unevenness is likely to occur. In the amount of coated paper, coating unevenness is conspicuous and the appearance is lowered (see Patent Document 3).

顔料として脱墨フロスを焼成、粉砕して得られた再生粒子凝集体を使用する技術も開示されているが、再生粒子凝集体は炭酸カルシウムよりも高い白紙光沢度を有する一方で白色度に劣り、クレーよりも高い白色度が得られる一方で白紙光沢度に劣るため、クレー及び炭酸カルシウムの代替顔料として使用することは可能だが、高い白色度及び白紙光沢度を有する塗工紙を得ることはできなかった(特許文献4を参照)。
Although a technique using a regenerated particle aggregate obtained by firing and pulverizing deinked floss as a pigment is also disclosed, the regenerated particle aggregate has a higher white paper gloss than calcium carbonate while being inferior in whiteness. The white paper has higher whiteness than clay, but is inferior in white paper gloss, so it can be used as an alternative pigment for clay and calcium carbonate, but it is possible to obtain coated paper with high whiteness and white paper gloss. It was not possible (see Patent Document 4).

上記のごとく、A3コート紙と同程度の白色度、白紙光沢度、表面強度を有し、耐ブリスター性に優れる微塗工紙は未だ得られていなかった。   As described above, a finely coated paper having whiteness, white paper glossiness and surface strength comparable to those of A3 coated paper and excellent in blister resistance has not been obtained.

特開2005−154951号公報JP 2005-154951 A 特開2007−46189号公報JP 2007-461189 A 特開2004−360104号公報JP 2004-360104 A 特開2007−197879号公報JP 2007-197879 A

本発明においては、高い白色度、白紙光沢度、表面強度を有し、耐ブリスター性に優れる塗工紙を提供することを課題とする。更には不透明度が高く、フィルム転写型ロールコーターを用いて塗工速度1300m/分以上と高速で顔料塗工層を設けた場合においても、ミストの飛散を発生させずに製造可能な塗工紙を提供することを課題とする。   An object of the present invention is to provide a coated paper having high whiteness, white paper glossiness, surface strength and excellent blister resistance. Further, coated paper that has high opacity and can be produced without causing mist scattering even when a pigment coating layer is provided at a coating speed of 1300 m / min or higher using a film transfer type roll coater. It is an issue to provide.

本発明は上記課題を改善するため鋭意検討した結果、基紙上に澱粉または澱粉誘導体を主成分とする下塗り塗工層を、片面あたり0.5〜1.0g/mの塗工量で設け、下塗り塗工層上に顔料及び接着剤を主成分とする上塗り顔料塗工層を設け、前記顔料が、0.1μmごとに集計した粒子径の分布において、0.1μm以上0.8μm未満の範囲に極大値を有する粒子径分布を持つことで、高い白色度、白紙光沢度、表面強度を有し、耐ブリスター性に優れた塗工紙が得られることを見出し、発明を完成させるに至った。 As a result of diligent studies to improve the above problems, the present invention provides an undercoat coating layer mainly composed of starch or starch derivative on the base paper at a coating amount of 0.5 to 1.0 g / m 2 per side. In addition, an overcoat pigment coating layer mainly composed of a pigment and an adhesive is provided on the undercoat coating layer, and the pigment has a particle size distribution of 0.1 μm or more and less than 0.8 μm in a particle size distribution every 0.1 μm. By having a particle size distribution with a maximum value in the range, it was found that a coated paper having high whiteness, white paper glossiness, surface strength and excellent blister resistance was obtained, and the invention was completed. It was.

本発明によれば、高い白色度、白紙光沢度、表面強度を有し、耐ブリスター性に優れた塗工紙を得ることができる。   According to the present invention, a coated paper having high whiteness, white paper glossiness, surface strength and excellent blister resistance can be obtained.

再生粒子の製造設備フローの一部構成例Partial configuration example of recycled particle manufacturing equipment flow

本発明は、基紙上に澱粉または澱粉誘導体を主成分とする下塗り塗工層を片面あたり0.5〜1.0g/mの塗工量で設け、下塗り塗工層上に顔料及び接着剤を主成分とする上塗り顔料塗工層を設け、前記顔料が、0.1μmごとに集計した粒子径の分布において、0.1μm以上0.8μm未満に極大値を有する粒子径分布を持つことを特徴とする塗工紙である。上記構成とすることにより、白色度が77%以上、白紙光沢度が35%以上であり、表面強度及び耐ブリスター性に優れた塗工紙を得ることができる。 In the present invention, an undercoat coating layer mainly composed of starch or a starch derivative is provided on a base paper at a coating amount of 0.5 to 1.0 g / m 2 per side, and a pigment and an adhesive are provided on the undercoat coating layer. In the particle size distribution aggregated every 0.1 μm, the pigment has a particle size distribution having a maximum value of 0.1 μm or more and less than 0.8 μm. It is a characteristic coated paper. By setting it as the said structure, whiteness is 77% or more, white paper glossiness is 35% or more, and the coated paper excellent in surface strength and blister resistance can be obtained.

<基紙>
まず、本実施形態に係る塗工紙を構成する基紙について説明する。
基紙は、通常の原料パルプを抄紙して得られるものであればよい。該原料パルプにも特に限定がなく、例えば未晒針葉樹パルプ(NUKP)、未晒広葉樹パルプ(LUKP)、晒針葉樹パルプ(NBKP)、晒広葉樹パルプ(LBKP)等の化学パルプ;ストーングランドパルプ(SGP)、加圧ストーングランドパルプ(PGW)、リファイナーグランドパルプ(RGP)、ケミグランドパルプ(CGP)、サーモグランドパルプ(TGP)、グランドパルプ(GP)、サーモメカニカルパルプ(TMP)、ケミサーモメカニカルパルプ(CTMP)、リファイナーメカニカルパルプ(RMP)等の機械パルプ;雑誌古紙、チラシ古紙、オフィス古紙等から製造される離解・脱墨古紙パルプ、離解・脱墨・漂白古紙パルプ等の古紙パルプ等があげられ、これらの中から1種又は2種以上を選択し、その割合を調整して用いることができる。
<Base paper>
First, the base paper which comprises the coated paper which concerns on this embodiment is demonstrated.
The base paper should just be obtained by papermaking a normal raw material pulp. The raw material pulp is not particularly limited. For example, chemical pulp such as unbleached softwood pulp (NUKP), unbleached hardwood pulp (LUKP), bleached softwood pulp (NBKP), bleached hardwood pulp (LBKP), etc .; Stone Grand Pulp (SGP) ), Pressurized Stone Grand Pulp (PGW), Refiner Grand Pulp (RGP), Chemi Grand Pulp (CGP), Thermo Grand Pulp (TGP), Grand Pulp (GP), Thermo Mechanical Pulp (TMP), Chemi Thermo Mechanical Pulp ( CTMP), refiner mechanical pulp (RMP) and other mechanical pulp; magazine waste paper, leaflet waste paper, waste paper pulp manufactured from office waste paper, etc., waste paper pulp such as disaggregation, deinking, bleached waste paper pulp, etc. Select one or more from these, and the ratio It can be used to adjust.

上記原料パルプに、内添の填料として従来製紙用途で用られている填料を添加することができる。填料としては、例えば軽質炭酸カルシウム、タルク、二酸化チタン、クレー、焼成クレー、合成ゼオライト、シリカ等の無機填料や、ポリスチレンラテックス、尿素ホルマリン樹脂等が挙げられる。填料の配合量は特に限定されないが、紙中灰分で2〜20質量%が好ましく、5〜15質量%がより好ましい。紙中灰分が2質量%を下回ると、紙の柔軟性が低下し、得られる塗工紙の白紙光沢度が向上しにくいため好ましくない。紙中灰分が20質量%を超過すると、微塗工紙の引張強度が低下し、製造時や印刷時に紙切れが発生しやすくなるため好ましくない。尚、本発明の灰分とは、JISP8251「紙、板紙及びパルプ−灰分試験方法−525℃燃焼法」に準じて測定した値とする。   A filler conventionally used for papermaking can be added to the raw material pulp as an internal filler. Examples of the filler include inorganic fillers such as light calcium carbonate, talc, titanium dioxide, clay, calcined clay, synthetic zeolite, and silica, polystyrene latex, urea formalin resin, and the like. Although the compounding quantity of a filler is not specifically limited, 2-20 mass% is preferable with an ash content in paper, and 5-15 mass% is more preferable. When the ash content in the paper is less than 2% by mass, the flexibility of the paper is lowered, and the white paper glossiness of the coated paper to be obtained is hardly improved. If the ash content in the paper exceeds 20% by mass, the tensile strength of the finely coated paper is lowered, and paper breakage is likely to occur during production or printing, which is not preferable. The ash content of the present invention is a value measured according to JISP8251 “Paper, paperboard and pulp-ash content test method—525 ° C. combustion method”.

本実施形態においては、該原料パルプに、例えば内添サイズ剤、紙力向上剤、紙厚向上剤、歩留向上剤(各種合成高分子や澱粉又は澱粉誘導体等の水溶性高分子)、及びこれらの定着剤等の、通常塗工紙の基紙に配合される種々の添加剤を、その種類及び配合量を調整して内添することができる。   In the present embodiment, the raw material pulp includes, for example, an internal sizing agent, a paper strength improver, a paper thickness improver, a yield improver (various synthetic polymers and water-soluble polymers such as starch or starch derivatives), and Various additives such as these fixing agents, which are usually blended in the base paper of coated paper, can be internally added by adjusting their types and blending amounts.

前記のごとき抄紙原料をワイヤーパートにて抄紙し、次いでプレスパート、プレドライヤーパートに供して基紙を製造することができ、次いでコーターパートにて澱粉または澱粉誘導体を主成分とする下塗り塗工層と、顔料及び接着剤を主成分とする上塗り顔料塗工層を設けた後、アフタードライヤーパート、カレンダーパート、リールパート、ワインダーパート等に供して目的とする塗工紙を得ることができる。   Papermaking raw materials such as those mentioned above can be made in a wire part, then used in a press part and a pre-dryer part to produce a base paper, and then in a coater part, an undercoat coating layer mainly composed of starch or starch derivatives And after providing the top coat pigment coating layer which has a pigment and an adhesive as a main component, it can use for an after drier part, a calendar part, a reel part, a winder part, etc., and can obtain the target coated paper.

尚、後述する塗工層を設けた後に高白色度の塗工紙を得るには、基紙の白色度は、カラーアナライザー(型番:カラーi5、マクベスグレタグ社製)にて測定して70%以上、さらには75%以上であることが好ましい。このような基紙から印刷用塗工紙を製造した場合、後述するように、白色度を例えば77%以上、さらには80%以上とすることが可能になる。そして、このような白色度が80%以上の印刷用塗工紙を用いると、白色度が80%未満の印刷用塗工紙と比べて、例えばより高精彩で、コントラストの高い高級印刷物が得られる。   In addition, in order to obtain coated paper with high whiteness after providing a coating layer described later, the whiteness of the base paper is 70% as measured with a color analyzer (model number: color i5, manufactured by Macbeth Gretag). In addition, it is preferably 75% or more. When the coated paper for printing is manufactured from such a base paper, the whiteness can be set to, for example, 77% or more, further 80% or more, as will be described later. When such a coated paper for printing having a whiteness of 80% or more is used, for example, a high-quality printed material with higher definition and high contrast can be obtained compared to a coated paper for printing with a whiteness of less than 80%. It is done.

基紙の坪量に特に限定はないが、後述するように、目的とする塗工紙の坪量が好ましくは40〜100g/mであり、かつ印刷に耐ええる程度の剛性を有することを考慮して、該基紙の坪量は、通常25〜89g/m程度となるように調整することが好ましい。 Although there is no particular limitation on the basis weight of the base paper, as will be described later, the basis weight of the target coated paper is preferably 40 to 100 g / m 2 and has a rigidity enough to withstand printing. Considering this, it is preferable to adjust the basis weight of the base paper to be usually about 25 to 89 g / m 2 .

<下塗り塗工層>
基紙の片面又は両面には、澱粉又は澱粉誘導体を主成分とする下塗り塗工層を設ける。基紙の片面に本発明で規定する下塗り塗工層を1層設ける(ただし、他の面には別の下塗り塗工層を設けてもよいし、設けなくともよい)か、又は、基紙の両面に本発明で規定する下塗り塗工層をそれぞれ1層ずつ設けることが好ましい。
<Undercoat coating layer>
An undercoat coating layer mainly composed of starch or starch derivative is provided on one side or both sides of the base paper. Either one undercoat layer defined in the present invention is provided on one side of the base paper (however, another undercoat layer may or may not be provided on the other side), or the base paper It is preferable to provide one undercoat coating layer defined in the present invention on each of the two surfaces.

(澱粉又はその誘導体)
下塗り塗工層に用いる澱粉又は澱粉誘導体は、例えば酸化澱粉、ヒドロキシエチルエーテル化澱粉、酵素変性澱粉、生澱粉などの澱粉またはその誘導体等、一般に製紙用途で用いる澱粉又はその誘導体を使用することができる。澱粉又は澱粉誘導体を用いると、基紙への微粒顔料の沈み込みを防止しつつ、表面強度を十分に向上でき、かつ耐ブリスターに優れるため好ましい。
(Starch or its derivatives)
As the starch or starch derivative used in the undercoat coating layer, for example, starch such as oxidized starch, hydroxyethyl etherified starch, enzyme-modified starch, raw starch, etc., or starch or derivatives thereof generally used in papermaking applications may be used. it can. Use of starch or starch derivatives is preferable because it can sufficiently improve the surface strength while preventing the fine pigment from sinking into the base paper and is excellent in blister resistance.

上塗り塗工層が、0.1μmごとに集計した粒子径の分布において、0.1μm以上0.8μm未満の範囲に極大値を有する粒子径分布を持つ顔料を含有するので、粒子が小さい顔料が基紙内部にまで沈み込みやすいが、本発明のごとく下塗り塗工層として、澱粉又は澱粉誘導体を主成分とする塗工層を設けた場合は、0.1μm以上0.8μm未満の粒子の基紙への沈み込みを低減する効果が特に高いため、白紙光沢度に優れる塗工紙を得ることができる。   The top coat layer contains a pigment having a particle size distribution having a maximum value in the range of 0.1 μm or more and less than 0.8 μm in the particle size distribution counted every 0.1 μm. Although it is easy to sink into the inside of the base paper, when a coating layer mainly composed of starch or a starch derivative is provided as an undercoat coating layer as in the present invention, the base of particles of 0.1 μm or more and less than 0.8 μm is provided. Since the effect of reducing the sinking into the paper is particularly high, a coated paper having excellent white paper gloss can be obtained.

下塗り塗工層を設けない場合は、0.1μm以上0.8μm未満の顔料が基紙内部に沈み込みやすく白紙光沢度が低下するだけでなく、上塗り塗料中の接着剤も基紙に沈み込むため塗工層強度が弱くなり、表面強度に劣る塗工紙となるため好ましくない。また、下塗り塗工層として、顔料を含む顔料塗工層を設けた場合は、耐ブリスター性に劣る問題があるので、下塗り塗工層は顔料を含まない塗工層である。下塗り塗工層として澱粉又は澱粉誘導体を用いることで、0.1μm以上0.8μm未満の顔料粒子を最も効果的に塗工層内部に留まらせることができる。澱粉又は澱粉誘導体の中でも酸化澱粉を用いると、0.1μm以上0.8μm未満の顔料粒子を塗工層内部に最も留めやすく、表面強度及び耐ブリスター性に特に優れる塗工紙が得られるため好ましい。   When the undercoat coating layer is not provided, pigments of 0.1 μm or more and less than 0.8 μm are liable to sink into the base paper, and not only the glossiness of the white paper is lowered, but also the adhesive in the top coat sinks into the base paper. For this reason, the coating layer strength is weak, and the coated paper is inferior in surface strength. Further, when a pigment coating layer containing a pigment is provided as the undercoat coating layer, there is a problem inferior in blister resistance, so the undercoat coating layer is a coating layer containing no pigment. By using starch or starch derivatives as the undercoat coating layer, pigment particles having a size of 0.1 μm or more and less than 0.8 μm can be most effectively retained inside the coating layer. Among starches and starch derivatives, use of oxidized starch is preferable because pigment paper having a size of 0.1 μm or more and less than 0.8 μm is most easily retained inside the coating layer, and a coated paper having particularly excellent surface strength and blister resistance can be obtained. .

澱粉又は澱粉誘導体の塗布量(固形分付着量)は片面あたり0.5〜1.0g/mであり、好ましくは0.6〜0.8g/mである。0.5g/m未満では被覆性が悪く、未塗工部分が発生して白紙光沢度が低下しやすいだけでなく、原紙の低い表面強度を塗工層で補えず、表面強度が向上しにくいため好ましくない。1.0g/mを超えると白紙光沢度及び表面強度は向上するものの、下塗り塗工層の厚みが増すため、印刷後乾燥時に基紙内部で発生する水蒸気を透過させにくくなり、耐ブリスター性に劣るため好ましくない。 The coating amount (solid content adhesion amount) of starch or starch derivative is 0.5 to 1.0 g / m 2 , preferably 0.6 to 0.8 g / m 2 per side. If it is less than 0.5 g / m 2 , the coating property is poor, and not only the uncoated part is generated and the glossiness of the white paper is likely to decrease, but the low surface strength of the base paper cannot be compensated by the coating layer, and the surface strength is improved. It is not preferable because it is difficult. If it exceeds 1.0 g / m 2 , the glossiness and surface strength of the white paper will improve, but the thickness of the undercoat coating layer will increase, making it difficult to permeate water vapor generated inside the base paper during drying after printing, and blister resistance. It is not preferable because it is inferior.

このような澱粉又は澱粉誘導体は、例えば、2ロールサイズプレスコーターやゲートロールコーター、ブレードメタリングサイズプレスコーター、ロッドメタリングサイズプレスコーター、又はシムサイザーやJFサイザー等のフィルム転写型ロールコーター等の塗工機によって塗布することができる。フィルム転写型ロールコーターは表面被覆性が高いため、印刷適性を効果的に向上できるため好ましい。上記以外の塗工機、例えばブレードコーターやエアーナイフコーターは、低塗工量では被覆性が悪くなり、非塗工部分が生じやすいため好ましくなく、スプレーコーターやカーテンコーターについては、均一な塗工が得られず、表面強度や耐ブリスター性に劣るため好ましくない。   Such a starch or starch derivative is applied to, for example, a two-roll size press coater, a gate roll coater, a blade metering size press coater, a rod metering size press coater, or a film transfer type roll coater such as a shim sizer or a JF sizer. Can be applied by machine tool. A film transfer type roll coater is preferable because it has high surface coverage and can effectively improve printability. Coating machines other than those described above, such as blade coaters and air knife coaters, are unfavorable because the coatability is poor at low coating amounts and non-coated parts are likely to occur, and uniform coating is required for spray coaters and curtain coaters. Is not obtained, and the surface strength and blister resistance are inferior.

(澱粉以外の水溶性高分子)
上記澱粉又は澱粉誘導体以外にも、従来製紙用途で塗工用途に用いられる水溶性高分子を併用することができる。例えば、ポリアクリルアミド、ポリビニルアルコールなどの合成高分子、耐水化や表面強度向上を目的とした紙力増強剤、サイズ性付与を目的とした外添サイズ剤、または一般に表面処理剤として通常使用されるものを単独で、あるいはこれらを数種類混合して使用することができる。
(Water-soluble polymer other than starch)
In addition to the starch or starch derivative, a water-soluble polymer conventionally used for coating in papermaking can be used in combination. For example, it is usually used as a synthetic polymer such as polyacrylamide and polyvinyl alcohol, a paper strength enhancer for improving water resistance and surface strength, an external sizing agent for imparting sizing properties, or a surface treatment agent in general. These can be used alone or in admixture of several.

〔平坦化処理(プレカレンダー)〕
下塗り塗工後は、上塗り塗工(顔料塗工)を行う前に、プレカレンダーによる平坦化処理を行うことが好ましい。プレカレンダーは、金属ロールと弾性ロールを組み合わせたソフトカレンダーが、表面の改良性が高いため好ましい。プレカレンダーは、1段又は必用に応じ2段以上の組合せで行うこともできる。プレカレンダーでの処理により、澱粉又は澱粉誘導体を塗布した後の原紙表面を平坦化処理するとともに、後のカレンダーで過度の平坦化処理を要しないことで、紙の耐ブリスター性を低下させることなく、原紙表面の白紙光沢度を向上させることが可能になる。また、原紙表面を平坦化処理することで上塗り塗工の塗工性を向上させ、塗工液の塗工ムラを抑えることができるだけでなく、特に上塗り塗工層をフィルム転写型ロールコーターで設ける場合は、ミストが飛散しにくくなる効果があり、例えば塗工速度が毎分1300m以上であっても、十分にミストの飛散を防止することができるため好ましい。プレカレンダーの線圧は、好ましくは10〜80kN/mであり、より好ましくは10〜50kN/mである。10kN/m未満であると、澱粉又は澱粉誘導体を塗布した後の原紙の平坦化が進まず、また、80kN/mを超過すると、必要以上に原紙を圧迫するため、耐ブリスター性に劣るため好ましくない。
[Flatening treatment (pre-calendar)]
After the undercoat coating, it is preferable to perform a pre-calender flattening treatment before performing the topcoat coating (pigment coating). As the pre-calender, a soft calender in which a metal roll and an elastic roll are combined is preferable because the surface is highly improved. The pre-calendar can be performed in one stage or a combination of two or more stages as required. By pre-calender treatment, the surface of the base paper after applying starch or starch derivative is flattened, and it does not require excessive flattening treatment in the later calendar, without reducing the blister resistance of the paper. It becomes possible to improve the glossiness of the blank paper on the surface of the base paper. In addition, the surface of the base paper can be flattened to improve the coatability of the topcoat and reduce coating unevenness of the coating solution. In particular, the topcoat coating layer is provided by a film transfer type roll coater. In the case, there is an effect that the mist is hardly scattered. For example, even when the coating speed is 1300 m or more per minute, the mist can be sufficiently prevented from being scattered. The linear pressure of the pre-calender is preferably 10 to 80 kN / m, more preferably 10 to 50 kN / m. If it is less than 10 kN / m, flattening of the base paper after applying the starch or starch derivative does not proceed, and if it exceeds 80 kN / m, the base paper is compressed more than necessary, so it is preferably inferior in blister resistance. Absent.

<上塗り塗工層>
基紙の片面又は両面には、顔料及び接着剤を主成分とする上塗り塗工層を設ける。基紙の片面に本発明で規定する上塗り塗工層を1層設ける(ただし、他の面には別の上塗り塗工層を設けてもよいし、設けなくともよい)か、又は、基紙の両面に本発明で規定する上塗り塗工層をそれぞれ1層ずつ設けることが好ましい。
<Topcoat coating layer>
On one side or both sides of the base paper, a top coat layer mainly composed of a pigment and an adhesive is provided. One overcoating layer specified in the present invention is provided on one side of the base paper (however, another overcoating layer may or may not be provided on the other side), or the base paper It is preferable to provide one each of the top coat layers defined in the present invention on both sides.

(顔料)
顔料は、粒子径分布を規定することで本発明の白色度、白紙光沢度、表面強度、耐ブリスター性を向上させる効果が得られる。粒子径分布は、0.1μmごとに集計した粒子径の分布において、0.1μm以上0.8μm未満の範囲に極大値を有する必要があり、当該構成にすることで、白色度が77%以上、白紙光沢度が35%以上であり、表面強度及び耐ブリスター性に優れる塗工紙を得ることができる。粒子径分布は0.1μmごとに集計することが好ましい。0.05μmごとでは分布が細かくなりすぎ、白紙光沢度等の効果に劣る場合でも極大値が出やすくなる可能性があり、0.2μmごとでは極大値が現れない可能性があるため好ましくない。下塗り塗工層として澱粉又は澱粉誘導体を主成分とする顔料塗工層を片面あたり0.5〜1.0g/m設けた後、粒子径の分布において0.1μm以上0.8μm未満の範囲に極大値を有する顔料及び接着剤を主成分とする顔料塗工層を設けることで、顔料塗工層の塗工量が片面あたり7.5g/m以下の微塗工紙においても、A3コート紙と同程度の白色度、白紙光沢度、表面強度を有し、耐ブリスター性に優れる微塗工紙を得ることができるとの利点がある。
(Pigment)
The pigment has the effect of improving the whiteness, white paper gloss, surface strength, and blister resistance of the present invention by defining the particle size distribution. The particle size distribution needs to have a maximum value in the range of 0.1 μm or more and less than 0.8 μm in the particle size distribution aggregated every 0.1 μm, and with this configuration, the whiteness is 77% or more. Further, a coated paper having a white paper glossiness of 35% or more and excellent surface strength and blister resistance can be obtained. The particle size distribution is preferably aggregated every 0.1 μm. The distribution becomes too fine every 0.05 μm, and even when the effect such as the glossiness of white paper is inferior, there is a possibility that the maximum value is likely to be generated, and the maximum value may not appear every 0.2 μm, which is not preferable. After providing 0.5 to 1.0 g / m 2 of a pigment coating layer mainly composed of starch or starch derivative as an undercoat coating layer, a range of 0.1 μm or more and less than 0.8 μm in particle size distribution By providing a pigment coating layer whose main component is a pigment having a maximum value and an adhesive, the coating amount of the pigment coating layer is A3 even on a fine coated paper of 7.5 g / m 2 or less per side. There is an advantage that a finely coated paper having whiteness, white paper glossiness and surface strength comparable to that of coated paper and excellent in blister resistance can be obtained.

粒子径の分布において0.1μm以上0.8μm未満の範囲に極大値を有する顔料に加えて、0.8μm以上2.0μm未満の範囲に極大値を有する顔料を併用すると、塗工層表面の平坦性が高く、白紙光沢度が良好な塗工紙が得られるため好ましい。これは、0.8μm以上2.0μm未満と比較的粒径の大きい顔料の隙間に、0.1μm以上0.8μm未満と粒径の小さい顔料が組み合わされることで、0.1μm以上0.8μm未満の顔料粒子を塗工層中に留めやすくなる一方で、塗工層中の空隙性が改善されるためと考えられる。0.8μm以上2.0μm未満の顔料粒子が少なく、小粒子径の顔料で構成された塗工層では、塗工層中の空隙が小さくなり、水蒸気の透過性に劣るため耐ブリスター性が悪化しやすい。逆に2.0μm以上の粒子径が大きい粒子と組み合わさると、0.1μm以上0.8μm未満の範囲に極大値を有する微小顔料が塗工層に留まらず基紙内部に浸透しやすくなるため、白紙光沢度に劣る塗工紙となる恐れがある。上述のとおり0.8μm以上2.0μm未満の範囲に極大値を有する顔料を併用することで、より耐ブリスター性及び白紙光沢度に優れる塗工紙が得られるため好ましい。   In addition to the pigment having the maximum value in the range of 0.1 μm or more and less than 0.8 μm in the particle size distribution, when the pigment having the maximum value in the range of 0.8 μm or more and less than 2.0 μm is used in combination, This is preferable because a coated paper having high flatness and good white paper gloss can be obtained. This is because a pigment having a relatively large particle size of 0.8 μm or more and less than 2.0 μm is combined with a pigment having a particle size of 0.1 μm or more and less than 0.8 μm and 0.1 μm or more and 0.8 μm or less. This is considered to be because it is easy to retain less pigment particles in the coating layer, while the porosity in the coating layer is improved. In coating layers composed of pigments with a small particle diameter of 0.8 μm or more and less than 2.0 μm, the voids in the coating layer are small, and the water vapor permeability is poor, resulting in poor blister resistance. It's easy to do. Conversely, when combined with particles having a large particle size of 2.0 μm or more, the fine pigment having the maximum value in the range of 0.1 μm or more and less than 0.8 μm is likely to penetrate into the base paper not only in the coating layer. There is a risk that the coated paper is inferior in glossiness of white paper. As described above, it is preferable to use a pigment having a maximum value in the range of 0.8 μm or more and less than 2.0 μm because a coated paper having more excellent blister resistance and white paper gloss can be obtained.

粒子径の分布において0.1μm以上0.8μm未満の範囲に極大値を有する顔料粒子の配合量は、顔料100質量部のうち20〜80質量部が好ましく、30〜75質量部が更に好ましい。20質量部を下回ると、微細粒子由来の白紙光沢度が得られにくくなり、80質量部を上回ると、空隙のサイズが小さくなり耐ブリスター性に劣るだけでなく不透明性も低下すること、接着剤が顔料を固定しにくくなり表面強度が低下しやすくなるため好ましくない。   The blending amount of the pigment particles having a maximum value in the range of 0.1 μm or more and less than 0.8 μm in the particle size distribution is preferably 20 to 80 parts by mass, more preferably 30 to 75 parts by mass, out of 100 parts by mass of the pigment. When the amount is less than 20 parts by mass, it becomes difficult to obtain white paper glossiness derived from fine particles. When the amount is more than 80 parts by mass, not only the void size is reduced and the blister resistance is deteriorated, but also the opacity is lowered. However, it is not preferable because it is difficult to fix the pigment and the surface strength tends to be lowered.

粒子径の分布において0.8μm以上2.0μm未満の範囲に極大値を有する顔料粒子の配合量は、顔料100質量部のうち5〜30質量部が好ましく、10〜25質量部が更に好ましい。5質量部を下回ると、0.1μm以上0.8μm未満の範囲に極大値を有するような微細粒子を塗工層表面に留めにくく、充分な白紙光沢度が得られない可能性があるため好ましくない。30質量部を超過すると、微細粒子由来の白紙光沢度の向上効果により白紙光沢度が向上しやすいが、一方で、塗工層が密になりすぎて、耐ブリスター性が低下しやすく、白色度も低下するため好ましくない。   The blending amount of the pigment particles having a maximum value in the range of 0.8 μm or more and less than 2.0 μm in the particle size distribution is preferably 5 to 30 parts by mass, more preferably 10 to 25 parts by mass, out of 100 parts by mass of the pigment. If it is less than 5 parts by mass, it is difficult to retain fine particles having a maximum value in the range of 0.1 μm or more and less than 0.8 μm on the surface of the coating layer, and sufficient blank glossiness may not be obtained. Absent. If the amount exceeds 30 parts by mass, the glossiness of the blank paper is likely to be improved due to the effect of improving the glossiness of the blank paper derived from fine particles, but on the other hand, the coating layer becomes too dense and the blister resistance is likely to be lowered. Is also undesirable.

更に好ましくは、本発明では、粒子径の分布において0.1μm以上0.8μm未満の範囲に2つの極大値を有する顔料粒子を使用することが好ましい。具体的には、0.5μm以上0.8μm未満の範囲に極大値を有する顔料粒子と、0.1μm以上0.5μm未満の範囲に極大値を有する顔料粒子とを上塗り塗工層に含有すると、更に白紙光沢度及び耐ブリスター性に優れた塗工紙が得られるため好ましい。上塗り塗工層の顔料が0.1μm以上0.5μm未満の範囲、0.5μm以上0.8μm未満の範囲および0.8μm以上2.0μm未満の範囲に極大値を有することで、粒子径の大きい顔料と小さい顔料の組み合わせに加え、中程度の顔料を組み合わせることとなり、粒子間に形成される空隙を所定範囲とすることができるため、より水蒸気を透過しやすい塗工層とすることができ、より耐ブリスター性に優れた塗工紙が得られる。特に、上記範囲に極大値を有する顔料がない場合は、上述のとおり耐ブリスター性に劣るだけでなく、0.1μm以上0.5μm未満の範囲に極大値を有する微細粒子を塗工層表面に留めにくく、充分な白紙光沢度が得られない可能性があるため好ましくない。上記の構成とすることにより、粒子径の分布において0.1μm以上0.5μm未満の範囲に極大値を有する顔料を最も良く塗工層に留めることができるため、白紙光沢度及び耐ブリスター性に優れた塗工紙が得られるとの利点がある。   More preferably, in the present invention, it is preferable to use pigment particles having two maximum values in the range of 0.1 μm or more and less than 0.8 μm in the particle size distribution. Specifically, when the topcoat coating layer contains pigment particles having a maximum value in a range of 0.5 μm or more and less than 0.8 μm and pigment particles having a maximum value in a range of 0.1 μm or more and less than 0.5 μm. Furthermore, it is preferable because a coated paper having excellent white paper gloss and blister resistance can be obtained. The pigment of the top coat layer has a maximum value in the range of 0.1 μm or more and less than 0.5 μm, in the range of 0.5 μm or more and less than 0.8 μm, and in the range of 0.8 μm or more and less than 2.0 μm. In addition to the combination of large pigments and small pigments, medium pigments are combined, and the voids formed between the particles can be set within a predetermined range, so that it is possible to make the coating layer more easily permeable to water vapor. Thus, coated paper having more excellent blister resistance can be obtained. In particular, when there is no pigment having a maximum value in the above range, not only the blister resistance is inferior as described above, but also fine particles having a maximum value in the range of 0.1 μm or more and less than 0.5 μm on the surface of the coating layer. This is not preferable because it is difficult to fasten and a sufficient glossiness of white paper may not be obtained. With the above configuration, the pigment having the maximum value in the range of 0.1 μm or more and less than 0.5 μm in the particle size distribution can be best retained in the coating layer. There is an advantage that an excellent coated paper can be obtained.

上述のごとく、本発明においては、所定の範囲内に極大値を3つ有することで、白色度が80%以上、白紙光沢度が40%以上であり、表面強度及び耐ブリスター性に優れた塗工紙を得ることができる。この効果は、例えば顔料塗工層の塗工量が片面あたり7.5g/m以下の微塗工紙であっても得ることができるとの利点がある。 As described above, in the present invention, by having three maximum values within a predetermined range, the whiteness is 80% or more, the white paper glossiness is 40% or more, and the coating has excellent surface strength and blister resistance. A craft paper can be obtained. This effect has an advantage that it can be obtained, for example, even with a finely coated paper having a coating amount of the pigment coating layer of 7.5 g / m 2 or less per side.

顔料の種類は、一般に製紙用途で使用している顔料であれば特に限定されず、例えば、炭酸カルシウム、クレー(カオリン、ディッカイト、ナクライト、ハロイサイト、アンチゴライト、クリソタイル、パイロフィライト、モンモリロナイト、ヘクトライト、テトラシリリックマイカ、ナトリウムテニオライト、マーガライト、タルク、バーミキュライト、ザンソフィライト、緑泥石等)、二酸化チタン、酸化亜鉛、酸化珪素、非晶質シリカ、炭酸マグネシウム、炭酸バリウム、水酸化アルミニウム、アルミナ、水酸化カルシウム、水酸化マグネシウム、水酸化亜鉛等が挙げられ、必要に応じて1種類以上を組み合わせて使用することができる。   The type of pigment is not particularly limited as long as it is a pigment generally used in papermaking applications. For example, calcium carbonate, clay (kaolin, dickite, nacrite, halloysite, antigolite, chrysotile, pyrophyllite, montmorillonite, hector Light, tetrasilic mica, sodium teniolite, margarite, talc, vermiculite, xanthophyllite, chlorite, etc.), titanium dioxide, zinc oxide, silicon oxide, amorphous silica, magnesium carbonate, barium carbonate, aluminum hydroxide , Alumina, calcium hydroxide, magnesium hydroxide, zinc hydroxide and the like, and may be used in combination of one or more as required.

上記顔料の中でも、目的の白色度、白紙光沢度を得るためには、炭酸カルシウム及び/又はクレーを使用することが好ましい。炭酸カルシウムを使用すると白色度に優れた塗工紙となりやすく、クレーを用いると、白紙光沢度に優れた塗工紙となりやすい。特に炭酸カルシウムを使用することが好ましい。   Among the above pigments, calcium carbonate and / or clay is preferably used in order to obtain the desired whiteness and white paper gloss. When calcium carbonate is used, it becomes easy to obtain coated paper with excellent whiteness, and when clay is used, it becomes easy to become coated paper with excellent white paper gloss. It is particularly preferable to use calcium carbonate.

(再生粒子凝集体)
本発明では、粒子径の分布において0.8μm以上2.0μm未満の範囲に極大値を有する顔料として、再生粒子凝集体を使用すると、特に表面強度及び耐ブリスター性に優れた塗工紙が得られるため好ましい。
(Regenerated particle aggregate)
In the present invention, when a regenerated particle aggregate is used as a pigment having a maximum value in the range of 0.8 μm or more and less than 2.0 μm in the particle size distribution, a coated paper having particularly excellent surface strength and blister resistance is obtained. Therefore, it is preferable.

(再生粒子凝集体の製造工程)
再生粒子は、古紙パルプを製造する古紙処理設備の脱墨工程においてパルプ繊維から分離された脱墨フロスを主原料として、前記主原料を脱水、乾燥、燃焼及び粉砕工程を経て得られる。前記燃焼工程が、第1燃焼炉と、第1燃焼炉にて燃焼された脱墨フロスを再度燃焼する、後の第2燃焼炉とを有する、少なくとも2段階の燃焼工程を有し、前記第1燃焼炉は300℃以上〜500℃未満で燃焼処理を行う。
(Production process of regenerated particle aggregate)
The recycled particles are obtained by using the deinked floss separated from the pulp fiber in the deinking process of the used paper processing equipment for producing the used paper pulp as a main raw material, and then dehydrating, drying, burning and grinding the main raw material. The combustion process includes at least a two-stage combustion process including a first combustion furnace and a second combustion furnace after which the deinking floss burned in the first combustion furnace is burned again. 1 combustion furnace performs a combustion process at 300 degreeC or more and less than 500 degreeC.

次に再生粒子の製造工程を詳述する。
図1に、再生粒子の製造設備フローの一部構成例(乾燥・燃焼工程、及び燃焼工程を含む設備例)を示した。本設備には、各種センサーが備わっており、被燃焼物や設備の状態、処理速度のコントロール等を行っている。
Next, the production process of regenerated particles will be described in detail.
FIG. 1 shows a partial configuration example (an example of equipment including a drying / combustion process and a combustion process) of a production facility flow of regenerated particles. This equipment is equipped with various sensors, and controls the state of combustibles, equipment, and processing speed.

図示しない、古紙パルプを製造する脱墨工程においてパルプ繊維から分離された脱墨フロスは、種々の操作を経て、同じく図示しない公知の脱水設備により脱水される。脱水後の原料は、40%以上、望ましは90%未満、特には45%〜70%、より好適には50%超〜60%の高含水状態とすることが望ましい。   The deinking floss separated from the pulp fiber in the deinking process for producing waste paper pulp (not shown) is dehydrated by a known dehydration equipment (not shown) through various operations. It is desirable that the raw material after dehydration has a high water content of 40% or more, preferably less than 90%, particularly 45% to 70%, more preferably more than 50% to 60%.

かかる脱水後の原料10は、望ましくは、粉砕機(または解砕機)により40mm以下の粒子径に粉砕しておく。かかる原料10が貯槽12から切り出されて、本体が横置きで中心軸周りに回転する内熱キルン炉である、第1燃焼炉14の一方側から装入機15により装入される。第1燃焼炉14の一方側には、排ガスチャンバー16が、他方側には排出チャンバー18が設けられている。排出チャンバー18を貫通して、熱風が第1燃焼炉14の他方側から吹き込まれ、前記一方側から装入され、第1燃焼炉14の回転に伴って前記他方側に順次移送される原料の乾燥及び燃焼を行うようになっている。   The material 10 after such dehydration is desirably pulverized to a particle size of 40 mm or less by a pulverizer (or pulverizer). The raw material 10 is cut out from the storage tank 12 and charged by a charging machine 15 from one side of the first combustion furnace 14 which is an internal heat kiln furnace in which the main body is placed horizontally and rotates around the central axis. An exhaust gas chamber 16 is provided on one side of the first combustion furnace 14, and an exhaust chamber 18 is provided on the other side. Hot air is blown from the other side of the first combustion furnace 14 through the discharge chamber 18, charged from the one side, and sequentially transferred to the other side as the first combustion furnace 14 rotates. It is designed to dry and burn.

ここで、第1燃焼炉14内に吹き込む熱風は、酸素濃度が0.2%〜20%となるようにするのが望ましい。炉内温度としては、300℃以上〜500℃未満、より望ましくは400℃以上〜500℃未満、特に400℃以上〜450℃未満が望ましい。熱風は、バーナー20Aを備える熱風発生炉20から吹き込まれる。   Here, it is desirable that the hot air blown into the first combustion furnace 14 has an oxygen concentration of 0.2% to 20%. The temperature in the furnace is preferably 300 ° C. or more and less than 500 ° C., more preferably 400 ° C. or more and less than 500 ° C., and particularly preferably 400 ° C. or more and less than 450 ° C. Hot air is blown from a hot air generating furnace 20 provided with a burner 20A.

排ガスチャンバー16からは、乾燥・燃焼に供した排ガスが再燃焼室22に送り込まれる。排ガス中に含まれる燃焼物の微粉末は、排ガスチャンバー16の下部から排出され、再利用される。排ガスは、再燃焼室22でバーナーにより再燃焼が行われ、予冷器24により予冷された後、熱交換器26を通し、誘引ファン28により煙突30から排出される。ここで、熱交換器26は外気を昇温した後に、熱風発生炉20に送られ、第1燃焼炉14から吹き込まれる熱風の用に供せられ、排ガスチャンバー16からの排ガスの熱を回収するようにしてある。排ガスの処理は、排ガス中に含まれる有害物質の除去に有効である。   From the exhaust gas chamber 16, exhaust gas subjected to drying and combustion is sent into the recombustion chamber 22. The fine powder of the combustion material contained in the exhaust gas is discharged from the lower part of the exhaust gas chamber 16 and reused. The exhaust gas is recombusted by the burner in the recombustion chamber 22, precooled by the precooler 24, passed through the heat exchanger 26, and discharged from the chimney 30 by the induction fan 28. Here, after raising the temperature of the outside air, the heat exchanger 26 is sent to the hot air generating furnace 20 and used for the hot air blown from the first combustion furnace 14 to recover the heat of the exhaust gas from the exhaust gas chamber 16. It is like that. The treatment of exhaust gas is effective for removing harmful substances contained in the exhaust gas.

第1燃焼炉14において乾燥及び燃焼処理を経た燃焼物は、本体が横置きで中心軸周りに回転する外熱キルン炉である、第2燃焼炉32に装入される。この装入される燃焼物の粒径としては、40mm以下が好適である。第2燃焼炉32での熱源としては、第2燃焼炉32内の温度コントロールが容易で長手方向の温度制御が容易な電気による調整が好適であり、したがって、電気ヒーターにより間接的に第1燃焼炉14から得られる燃焼物を再び燃焼させる外熱式の第2燃焼炉32であることが望ましい。   Combustion products that have undergone drying and combustion treatment in the first combustion furnace 14 are charged into a second combustion furnace 32 that is an external heat kiln furnace in which the main body is placed horizontally and rotates around the central axis. The particle size of the combusted material to be charged is preferably 40 mm or less. As a heat source in the second combustion furnace 32, it is preferable to use an electric adjustment that allows easy temperature control in the second combustion furnace 32 and easy temperature control in the longitudinal direction. Therefore, the first combustion is indirectly performed by an electric heater. It is desirable that the second combustion furnace 32 be of an external heating type in which the combustion product obtained from the furnace 14 is burned again.

第2燃焼炉32においては、酸素濃度を調整する空気あるいは酸素の供給機構(図示せず)にて酸素濃度が5%〜20%、望ましくは10%〜20%、特に望ましくは10%〜15%となるように燃焼するのが望ましい。温度としては、550℃〜780℃、望ましくは600℃〜750℃が望ましい。また、第2燃焼炉32内での滞留時間は60分以上、より好適には60分〜240分、特には90分〜150分、最適には120分〜150分が、残カーボンを完全に燃焼させるに望ましい。   In the second combustion furnace 32, the oxygen concentration is 5% to 20%, preferably 10% to 20%, particularly preferably 10% to 15% by an air or oxygen supply mechanism (not shown) for adjusting the oxygen concentration. It is desirable to burn so that it becomes%. The temperature is preferably 550 ° C. to 780 ° C., more preferably 600 ° C. to 750 ° C. Further, the residence time in the second combustion furnace 32 is 60 minutes or more, more preferably 60 minutes to 240 minutes, particularly 90 minutes to 150 minutes, and optimally 120 minutes to 150 minutes. Desirable to burn.

燃焼が終了した再生粒子は、冷却機34により冷却された後、振動篩機などの粒径選別機36により選別され、湿式粉砕機等を用いた粉砕工程で目的の粒子径に調整された燃焼物が燃焼品サイロ38に一時貯留され、顔料や填料の用途先に仕向けられる。   The regenerated particles that have been burned are cooled by a cooler 34, and then sorted by a particle size sorter 36 such as a vibration sieve, and the combustion is adjusted to a target particle size in a grinding process using a wet grinding machine or the like. The material is temporarily stored in the combustion product silo 38 and is sent to the application destination of the pigment or filler.

なお、脱墨フロスを原料として用いた場合を例示したが、脱墨フロスを主原料に、抄紙工程における製紙スラッジ等の他製紙スラッジを適宜混入させたものを原料とした燃焼物であってもよい。   In addition, although the case where deinking floss was used as a raw material was illustrated, even if it is a combustion thing which used as a raw material what mixed other papermaking sludges, such as papermaking sludge in a papermaking process, with deinking floss as a main raw material Good.

本実施形態の塗工紙では、以上の再生粒子を、塗工層の顔料として用いることができる。この再生粒子は、脱墨フロスを焼成して得られる循環使用が可能なものであるので、廃棄物としての埋立等の処分が不要であり、環境負荷の低減と、省資源化に大きく貢献するものである。また、原料が古紙処理工程で生じる脱墨フロスであるので、安価であり、新たな天然無機鉱物の使用量を抑えることができ、製造コストが充分に削減されるという利点がある。   In the coated paper of this embodiment, the above regenerated particles can be used as a pigment for the coating layer. These recycled particles can be recycled and used by firing deinked floss, so there is no need to dispose of landfills as waste, contributing greatly to reducing environmental impact and saving resources. Is. Further, since the raw material is deinked floss generated in the waste paper processing step, there is an advantage that it is inexpensive, the amount of new natural inorganic mineral used can be suppressed, and the manufacturing cost is sufficiently reduced.

加えて、第1燃焼炉の炉内温度が、300℃以上〜500℃未満と低温であるため、特に塗工層の顔料として用いた場合に、白色度の高い塗工紙が得られやすいため好ましい。   In addition, since the temperature in the furnace of the first combustion furnace is a low temperature of 300 ° C. or more to less than 500 ° C., particularly when used as a pigment for the coating layer, it is easy to obtain coated paper with high whiteness. preferable.

本発明では前記製造工程により得られた再生粒子をそのまま使用してもよいし、特許第3907688号公報や、特許第3935496号公報に記載の方法でシリカ被覆したものを使用してもよい。具体的には、前記製造工程で得られた再生粒子を珪酸アルカリ水溶液に添加・分散しスラリーを調製した後に、加熱攪拌しながら、液温70〜100℃で硫酸、塩酸、硝酸などの鉱酸の希釈液を添加し、シリカゾルを生成させ、最終反応液のpHを8.0〜11.0の範囲に調整することにより、再生粒子表面に粒子径10〜20nmのシリカゾル粒子を生成させて得られた白色顔料を使用できる。このシリカ被覆再生粒子は、カルシウム、ケイ素及びアルミニウムを、酸化物換算で30〜62:29〜55:9〜35の質量割合とすることで、シリカ析出効果による吸油性、不透明性を向上させることができる。   In the present invention, the regenerated particles obtained by the production process may be used as they are, or those coated with silica by the method described in Japanese Patent No. 3907688 or Japanese Patent No. 3935496 may be used. Specifically, after adding and dispersing the regenerated particles obtained in the above production process in an aqueous alkali silicate solution to prepare a slurry, a mineral acid such as sulfuric acid, hydrochloric acid, nitric acid, etc. at a liquid temperature of 70-100 ° C. while stirring with heating. Is added to form silica sol, and the pH of the final reaction solution is adjusted to the range of 8.0 to 11.0 to obtain silica sol particles having a particle diameter of 10 to 20 nm on the surface of the regenerated particles. White pigments can be used. This silica-coated regenerated particles improve the oil absorption and opacity due to the silica precipitation effect by making calcium, silicon and aluminum into a mass ratio of 30 to 62:29 to 55: 9 to 35 in terms of oxides. Can do.

上記方法で製造した再生粒子は、個々の粒子が幾つか集まって凝集した再生粒子凝集体を形成しており、ランチュウの肉瘤状のような、不定形な形をしている。この不定形性により、0.1μm以上0.8μm未満の範囲に極大値を有する小粒子径の顔料を塗工層に留めやすくなり、白紙光沢度が向上するため好ましい。これは、上記再生粒子凝集体を用いると、不定形のランチュウの肉瘤に阻害されて微粒顔料が塗工層内部まで入り込にくくなり、塗工層表面に留まりやすいため、塗工層表面の平坦性が更に向上して白紙光沢度が向上しやすいためと考えられる。同様の効果は毬栗状の顔料を用いても得られるが、その程度は、理由は不明だが再生粒子凝集体よりも低い。おそらく、突起の形状が針状である毬栗状顔料よりも、ランチュウの肉瘤状である再生粒子凝集体の方が、微粒顔料を留めやすいためと考えられる。特に、ランチュウの肉瘤状である再生粒子凝集体を用いることにより、顔料塗工層の塗工量が片面あたり7.5g/m以下の微塗工紙においても、A3コート紙と同程度の白紙光沢度及び表面強度を有する微塗工紙を得ることができるとの利点がある。 The regenerated particles produced by the above method form a regenerated particle aggregate in which several individual particles are aggregated, and have an irregular shape such as a lump-like mass. This irregular shape is preferable because a pigment having a small particle diameter having a maximum value in the range of 0.1 μm or more and less than 0.8 μm can be easily retained on the coating layer, and the glossiness of the white paper is improved. This is because when the above regenerated particle aggregate is used, the irregular pigments are hindered by the irregular mass of the ranchu, making it difficult for the fine pigment to penetrate into the coating layer and staying on the coating layer surface. This is considered to be because the glossiness is further improved and the glossiness of the white paper is easily improved. A similar effect can be obtained by using a chestnut-like pigment, but the degree is lower than that of the regenerated particle aggregate for unknown reasons. Probably, it is considered that the regenerated particle aggregates that are in the shape of a hunting goose are easier to retain the fine pigment than the chestnut-shaped pigments in which the shape of the protrusion is needle-shaped. In particular, by using a regenerated particle aggregate that is in the shape of a mass of ranchu, even in a fine coated paper having a coating amount of a pigment coating layer of 7.5 g / m 2 or less per side, it is the same level as that of A3 coated paper. There is an advantage that a finely coated paper having white paper glossiness and surface strength can be obtained.

粒子径の分布において0.8μm以上2.0μm未満の範囲に極大値を有する顔料として再生粒子凝集体を使用し、0.1μm以上0.5μm未満及び0.5μm以上0.8μm未満の範囲に極大値を有する顔料として炭酸カルシウムを使用することが好ましい。この際、前記顔料のうち、0.1μm以上0.5μm未満の炭酸カルシウムが30〜75質量%、0.5μm以上0.8μm未満の炭酸カルシウムが10〜55質量%、0.8μm以上2.0μm未満の顔料として再生粒子凝集体が5〜30質量%であることが好ましい。   The regenerated particle aggregate is used as a pigment having a maximum value in the range of 0.8 μm or more and less than 2.0 μm in the particle size distribution, and in the range of 0.1 μm or more and less than 0.5 μm and 0.5 μm or more and less than 0.8 μm. It is preferable to use calcium carbonate as a pigment having a maximum value. At this time, among the pigments, calcium carbonate of 0.1 μm or more and less than 0.5 μm is 30 to 75% by mass, calcium carbonate of 0.5 μm or more and less than 0.8 μm is 10 to 55% by mass, 0.8 μm or more. It is preferable that the regenerated particle aggregate is 5 to 30% by mass as a pigment of less than 0 μm.

0.1μm以上0.5μm未満及び0.5μm以上0.8μm未満の炭酸カルシウムの合計量は、70〜95質量%であることが好ましい。炭酸カルシウムが70質量%を下回ったり、再生粒子凝集体が30質量%を超過すると白色度に劣る可能性があり、炭酸カルシウムが95質量%を超過したり再生粒子凝集体が5質量%を下回ると白紙光沢度が低下する可能性があるため好ましくない。加えて、特に本発明のごとく、0.1μm以上0.5μm未満と小粒子径の炭酸カルシウムの基紙への沈み込みを防止するために、0.5μm以上0.8μm未満の中粒子径の炭酸カルシウムを併用した場合、小粒子径及び中粒子径の炭酸カルシウム顔料の合計量が70質量%を下回ったり、0.8μm以上2.0μm未満の顔料である再生粒子凝集体が30質量%を超過すると、白色度が低下したり、小粒子径及び中粒子径の炭酸カルシウムが95質量%を超過したり、0.8μm以上2.0μm未満の顔料である再生粒子凝集体が5質量%を下回ると、小粒子径及び中粒子径が基紙に沈み込みやすくなり、白紙光沢度が低下しやすいため好ましくない。   The total amount of calcium carbonate of 0.1 μm or more and less than 0.5 μm and 0.5 μm or more and less than 0.8 μm is preferably 70 to 95% by mass. If the calcium carbonate is less than 70% by mass or the regenerated particle aggregate exceeds 30% by mass, the whiteness may be inferior. The calcium carbonate exceeds 95% by mass or the regenerated particle aggregate is less than 5% by mass. This is not preferable because the glossiness of white paper may be lowered. In addition, as in the present invention, in order to prevent the calcium carbonate having a small particle size of 0.1 μm or more and less than 0.5 μm from sinking into the base paper, the medium particle size of 0.5 μm or more and less than 0.8 μm is preferably used. When calcium carbonate is used in combination, the total amount of small and medium-sized calcium carbonate pigments is less than 70% by mass, or regenerated particle aggregates that are pigments of 0.8 μm or more and less than 2.0 μm reduce 30% by mass. If it exceeds, whiteness will decrease, calcium carbonate with small and medium particle sizes will exceed 95% by mass, and regenerated particle aggregates that are pigments of 0.8 μm or more and less than 2.0 μm will have 5% by mass. If it is less than the range, the small particle size and the medium particle size are likely to sink into the base paper, and the glossiness of the white paper tends to decrease, which is not preferable.

上述のとおり、炭酸カルシウムの合計量が70〜95質量%であり、再生粒子凝集体が5〜30質量%であると、白色度、白紙光沢、表面強度が高く、耐ブリスター性に優れた塗工紙が得られるため好ましい。   As described above, when the total amount of calcium carbonate is 70 to 95% by mass and the regenerated particle aggregate is 5 to 30% by mass, the coating has high whiteness, white paper gloss, surface strength, and excellent blister resistance. It is preferable because a working paper is obtained.

上記再生粒子凝集体や毬栗状顔料を使用せず、他の一般的な粒子と微粒顔料とを併用した場合は、上記の微粒粒子を塗工層内部にまで入り込む作用を防止しにくくなるため、白紙光沢度及び表面強度に劣る傾向にある。   Without using the regenerated particle agglomerates or chestnut-like pigments, when using other common particles and fine pigments together, it is difficult to prevent the action of entering the fine particles into the coating layer, It tends to be inferior in glossiness and surface strength of blank paper.

尚、本発明で言う粒子径は、電子顕微鏡で撮影した顔料粒子について、粒子を内包できる最小の円(粒子の外接円)の直径とした。極大値は、粒子径0.1μmごとに顔料粒子の数を集計して粒子径の分布を求め、極大値の有無を判断した。   The particle diameter referred to in the present invention is the diameter of the smallest circle (particle circumscribed circle) that can enclose the particles of the pigment particles taken with an electron microscope. For the maximum value, the number of pigment particles was counted for each particle size of 0.1 μm to determine the particle size distribution, and the presence or absence of the maximum value was determined.

(接着剤)
上塗り塗工層の接着剤としては、一般的に製紙用途で使用できる接着剤を使用することができる。例えばカゼイン、大豆蛋白等の蛋白質類;メチルメタクリレート−ブタジエン共重合体ラテックス、スチレン−ブタジエン共重合体ラテックス等の共役ジエン系ラテックス、アクリル酸エステル及び/又はメタクリル酸エステルの重合体ラテックスもしくは共重合体ラテックス等のアクリル系ラテックス、エチレン−酢酸ビニル重合体ラテックス等のビニル系ラテックス、あるいはこれらの各種共重合体ラテックスをカルボキシル基等の官能基含有単量体で変性したアルカリ部分溶解性又は非溶解性のラテックス等のラテックス類;ポリビニルアルコール、オレフィン−無水マレイン酸樹脂、メラミン樹脂、尿素樹脂、ウレタン樹脂等の合成樹脂系接着剤;酸化澱粉、陽性化澱粉、エステル化澱粉、デキストリン等の澱粉又は澱粉誘導体;カルボキシメチルセルロース、ヒドロキシエチルセルロース等のセルロース誘導体等の、通常塗工紙に用いられる接着剤が例示され、これらの中から1種又は2種以上を選択して併用することができる。但し、澱粉類は顔料100質量部に対して固形分換算で3質量部を超えて配合すると、塗工層中で成膜し白色度が低下しやすいだけでなく、耐ブリスター性にも劣るため、配合量は好ましくは3質量部以下、より好ましくは1質量部以下である。
(adhesive)
As an adhesive for the top coat layer, an adhesive that can be generally used for papermaking can be used. For example, proteins such as casein and soybean protein; conjugated diene latex such as methyl methacrylate-butadiene copolymer latex and styrene-butadiene copolymer latex, polymer latex or copolymer of acrylate ester and / or methacrylate ester Acrylic latex such as latex, vinyl latex such as ethylene-vinyl acetate polymer latex, or various types of copolymer latex modified with a functional group-containing monomer such as a carboxyl group. Latex such as latex; synthetic resin adhesives such as polyvinyl alcohol, olefin-maleic anhydride resin, melamine resin, urea resin, urethane resin; starch or starch such as oxidized starch, positive starch, esterified starch, dextrin Derivatives; Bo carboxymethylcellulose, and cellulose derivatives such as hydroxyethyl cellulose, are adhesives exemplified usually used for coated paper, can be used in combination by selecting one or more from these. However, if the starch is blended in an amount exceeding 3 parts by mass in terms of solid content with respect to 100 parts by mass of the pigment, not only does the film form in the coating layer and the whiteness tends to decrease, but also the blister resistance is poor. The blending amount is preferably 3 parts by mass or less, more preferably 1 part by mass or less.

上塗り塗工層の接着剤としては、上記接着剤の中でも特にスチレン−ブタジエン共重合体ラテックスが接着性と熱安定性が高いため好ましい。スチレン−ブタジエン共重合体ラテックスは、少なくともスチレンとブタジエンを共重合して得られるラテックスであり、スチレンとブタジエンに加えて、メタクリル酸メチルとアクリロニトリルを共重合して得られるスチレン−ブタジエン−メタクリル酸メチル−アクリロニトリル共重合体ラテックスがより好ましい。   As the adhesive for the top coat layer, styrene-butadiene copolymer latex is particularly preferable among the adhesives because of its high adhesiveness and thermal stability. The styrene-butadiene copolymer latex is a latex obtained by copolymerizing at least styrene and butadiene, and is obtained by copolymerizing methyl methacrylate and acrylonitrile in addition to styrene and butadiene. -Acrylonitrile copolymer latex is more preferred.

なかでも、モノマー成分としてブタジエンを40〜65質量%含む重合体ラテックスを使用することが好ましく、45〜60質量%がより好ましい。ブタジエン成分が40質量%を下回ると、顔料への接着性が劣り、表面強度が低下して印刷時に白抜けトラブルが発生するため好ましくない。加えて、塗工層の柔軟性が低下するため、印刷後にインキが紙の白紙部分に接触してインキが白紙部分に転写する、擦れ汚れが発生しやすくなるため好ましくない。また、ブタジエン成分はスチレン成分に比べて顔料同士を接着しやすいため、65質量%を超過すると、塗工層の通気性が低下し印刷時にブリスター欠陥が発生しやすくなる傾向にある。   Especially, it is preferable to use the polymer latex which contains 40-65 mass% of butadiene as a monomer component, and 45-60 mass% is more preferable. When the butadiene component is less than 40% by mass, the adhesion to the pigment is inferior, the surface strength is lowered, and white spots are generated during printing, which is not preferable. In addition, since the flexibility of the coating layer is lowered, the ink comes into contact with the white paper portion of the paper after printing, and the ink is transferred to the white paper portion. Further, since the butadiene component is more likely to adhere the pigments than the styrene component, if it exceeds 65% by mass, the air permeability of the coating layer is lowered and blister defects tend to occur during printing.

ブタジエン成分を40〜65質量%、より好ましくは45〜60質量%の範囲で含有するラテックスを接着剤として用い、粒子径の分布において0.1μm以上0.8μm未満の粒子を顔料として用いることで、表面強度及び耐ブリスター性に優れた塗工紙を得ることができる。また、擦れ汚れをも低減できるとのメリットがある。   By using a latex containing a butadiene component in an amount of 40 to 65% by mass, more preferably 45 to 60% by mass, as an adhesive, and using particles having a particle size distribution of 0.1 μm or more and less than 0.8 μm as a pigment. A coated paper having excellent surface strength and blister resistance can be obtained. There is also an advantage that rubbing dirt can be reduced.

ブタジエン以外のモノマー成分としては、スチレンを10〜35質量%含むことが好ましく、より好ましくは15〜25質量%である。スチレン成分は塗工層に耐水性を付与する効果があるため、10質量%を下回ると、特にオフセット印刷では湿し水を吸いやすくなり、耐ブリスター性に劣るため好ましくない。スチレン成分はブタジエン成分に比べて硬く接着力に劣るため、35質量%を超過すると表面強度が低下するため好ましくない。加えて、擦れにより印刷インキを掻き取りやすくなり、擦れ汚れが悪化する傾向がある。上記のごとく、表面強度及び耐ブリスター性を向上させるには、上記のとおりラテックス中のブタジエン成分及び顔料の粒子径の分布に加えて、テラックス中のスチレン成分を10〜35質量%、好ましくは15〜25質量%とすることが好ましく、これにより、更に表面強度及び耐ブリスター性に優れ、擦れ汚れをも防止できる塗工紙を得ることができる。   The monomer component other than butadiene preferably contains 10 to 35% by mass of styrene, more preferably 15 to 25% by mass. Since the styrene component has an effect of imparting water resistance to the coating layer, if it is less than 10% by mass, it is not preferred because offset printing tends to absorb dampening water and is inferior in blister resistance. Since the styrene component is harder and less adhesive than the butadiene component, if it exceeds 35% by mass, the surface strength decreases, which is not preferable. In addition, it becomes easy to scrape the printing ink by rubbing, and the rubbing dirt tends to deteriorate. As described above, in order to improve the surface strength and the blister resistance, in addition to the distribution of the particle size of the butadiene component and pigment in the latex as described above, the styrene component in Terrax is 10 to 35% by mass, preferably 15%. It is preferable that the content be ˜25% by mass, whereby a coated paper that is further excellent in surface strength and blister resistance and can prevent rubbing and dirt can be obtained.

つまり、粒子径の分布において0.1μm以上0.8μm未満の粒子を顔料として用い、ブタジエン成分を40〜65質量%、スチレン成分を10〜35質量%含むラテックスを併用することで、表面強度及び耐ブリスター性に優れた塗工紙を得ることができる。また、擦れ汚れをも低減できるとのメリットがある。   That is, by using particles having a particle size distribution of 0.1 μm or more and less than 0.8 μm as a pigment and using a latex containing 40 to 65% by mass of a butadiene component and 10 to 35% by mass of a styrene component, surface strength and A coated paper having excellent blister resistance can be obtained. There is also an advantage that rubbing dirt can be reduced.

上塗り塗工液中の顔料と接着剤との割合は、顔料100質量部に対して、接着剤5〜10質量部であることが好ましく、6質量部〜8質量部であることが更に好ましい。含有量が5部を下回ると、顔料を十分に固定できず表面強度に劣るため好ましくない。10質量部を超過すると、ラテックスの造膜作用により、通気性が低下して耐ブリスター性が低下しやすいだけでなく、顔料由来の光沢性も低下しやすくなるため好ましくない。加えて、ラテックス単体では濃度が50質量%と低いため、塗料中に多く配合すると塗料濃度が低下しやすくなり、フィルム転写型ロールコーターで塗工する場合においてはミストが飛散しやすくなる傾向があり、塗料粕等の異物が発生するため好ましくない。   The ratio of the pigment and the adhesive in the topcoat coating liquid is preferably 5 to 10 parts by mass, more preferably 6 to 8 parts by mass with respect to 100 parts by mass of the pigment. If the content is less than 5 parts, the pigment cannot be sufficiently fixed and the surface strength is inferior. Exceeding 10 parts by mass is not preferable because the film-forming action of the latex not only reduces air permeability and blister resistance, but also tends to reduce pigment-derived gloss. In addition, since the concentration of latex alone is as low as 50% by mass, the coating concentration tends to decrease when blended in a large amount in the paint, and mist tends to be scattered when applied with a film transfer type roll coater. This is not preferable because foreign substances such as paint flaws are generated.

上記スチレン−ブタジエン共重合体ラテックス以外に加えて、上述した接着剤を併用することができる。   In addition to the styrene-butadiene copolymer latex, the above-described adhesive can be used in combination.

スチレン−ブタジエン共重合体ラテックスの構造は、粒子内部と表面部で構成成分やガラス転移温度が同じである単一型よりも、粒子内部と表面部で構成成分やガラス転移温度が異なるコア−シェル型や、粒子の内部から外部に向けて組成が連続的に変化している傾斜型を使用することが好ましい。特に傾斜型は、顔料を固定する効果が高く、配合量を最小限に抑えることができ、例えば顔料100質量部に対してラテックス5質量部程度であっても、0.1μm以上0.8μm未満の範囲に極大値を有する微細粒子を接着する効果が高く、充分な表面強度と白紙光沢を付与することができる。特に本発明のごとく高い白紙光沢度を有する塗工紙とするためには、白紙光沢度を低下させるラテックスは少ないことが好ましいが、従来一般の単一型のラテックスでは、配合量を5質量部程度とすると表面強度が低くなりやすく、白紙光沢と表面強度に優れた塗工紙は得られなかった。傾斜型の中でも、表面強度と白紙光沢のバランスを考慮して、粒子内部のTgは−30〜−10℃のものが好ましく、粒子外部の表層Tgは10〜30℃のものが好ましく、その差は20〜60℃が好ましい。内部Tgが−30℃未満又は−10℃を超過すると、充分な柔軟性が得られず表面強度が低下する可能性がある。表層Tgが10℃未満ではラテックスの接着作用が強く充分な耐ブリスター性が得られにくく、表層Tgが30℃を超過すると、充分な表面強度が得られない可能性があるため好ましくない。   The structure of the styrene-butadiene copolymer latex is different from the single type in which the constituent components and the glass transition temperature are the same in the interior and the surface portion of the particle, and the core and shell are different in the constituent components and the glass transition temperature in the interior and the surface portion. It is preferable to use a mold or an inclined mold whose composition is continuously changed from the inside to the outside of the particle. In particular, the gradient type has a high effect of fixing the pigment and can minimize the blending amount. For example, even if the latex is about 5 parts by mass with respect to 100 parts by mass of the pigment, it is 0.1 μm or more and less than 0.8 μm. The effect of adhering fine particles having a maximum value in the range is high, and sufficient surface strength and white paper gloss can be imparted. In particular, in order to obtain a coated paper having a high white paper glossiness as in the present invention, it is preferable that the amount of latex that lowers the white paper glossiness is small, but in a conventional single-type latex, the blending amount is 5 parts by mass. The surface strength tends to be low, and a coated paper excellent in white paper gloss and surface strength could not be obtained. Among the inclined types, in consideration of the balance between surface strength and white paper gloss, the Tg inside the particle is preferably -30 to -10 ° C, and the surface layer Tg outside the particle is preferably 10 to 30 ° C. Is preferably 20 to 60 ° C. If the internal Tg is less than −30 ° C. or exceeds −10 ° C., sufficient flexibility cannot be obtained and the surface strength may be lowered. If the surface layer Tg is less than 10 ° C., the adhesive action of the latex is strong and it is difficult to obtain sufficient blister resistance, and if the surface layer Tg exceeds 30 ° C., there is a possibility that sufficient surface strength cannot be obtained.

上記のとおりの顔料及び接着剤からなる塗料を、澱粉又は澱粉誘導体を片面あたり0.5〜1.0g/m下塗り塗工した原紙に塗布した場合、本発明の課題である、顔料塗工層の塗工量が両面で15g/m(片面あたり7.5g/m)以下と少ない微塗工紙でありながら、高い白色度、白紙光沢度、表面強度を有し、耐ブリスター性に優れる塗工紙を得ることができる。しかしながら、この塗工紙を、より効率良く製造するためには、塗料の濃度及び粘度を所定範囲に調整することが好ましい。 When the paint comprising the pigment and the adhesive as described above is applied to the base paper coated with 0.5 to 1.0 g / m 2 of starch or starch derivative per side, pigment coating, which is the subject of the present invention Although the coating amount of the layer is 15 g / m 2 (7.5 g / m 2 per side) or less on both sides, it has high whiteness, white paper gloss, surface strength, and blister resistance. Coated paper having excellent resistance can be obtained. However, in order to produce this coated paper more efficiently, it is preferable to adjust the concentration and viscosity of the paint within a predetermined range.

塗工方法は、公知の種々の方式により塗工されることができるが、特にフィルム転写方式により塗工されることが好ましい。フィルム転写方式は、塗工塗料をロールに塗工した後に、塗料を紙に転写する方式のため、低塗工量で基紙表面に均一な塗工層を形成できることから、均一で良好な白紙光沢度、表面強度、耐ブリスター性が得られるため好ましい。例えばツーロールサイズプレスのように塗工液の液溜りを形成し塗工する方式では、粒径の小さい顔料が基紙内部にまで入り込みやすい一方、粒径の大きい顔料が塗工層の表面に留まり、高い白紙光沢度が得られにくい。また、ブレード塗工方式の場合は、均一な厚さの塗工層が得られないため、塗工層の薄い部分と厚い部分で光沢ムラが発生し、見栄えに劣る塗工紙となるため好ましくない。   The coating method can be applied by various known methods, but is particularly preferably applied by a film transfer method. The film transfer method is a method in which the coating paint is applied to the roll after the coating paint is applied to the roll, so a uniform coating layer can be formed on the surface of the base paper with a low coating amount. Since glossiness, surface strength, and blister resistance are obtained, it is preferable. For example, in a method of forming a coating liquid pool such as a two-roll size press, a pigment with a small particle size can easily enter the inside of the base paper, while a pigment with a large particle size is applied to the surface of the coating layer. It is difficult to obtain high white paper glossiness. Also, in the case of the blade coating method, since a coating layer with a uniform thickness cannot be obtained, gloss unevenness occurs in the thin and thick portions of the coating layer, which is preferable because the coated paper is inferior in appearance. Absent.

特に塗工速度1300m/分以上の高速塗工を、フィルム転写型ロールコーターを用いて行った場合、ロール表面の塗料が紙に転写しにくく、転写しなかった塗料が飛散してミストが発生するミスト飛散トラブルが発生しやすくなる。特に本発明のごとく、粒子径の小さい顔料を用いる場合は、ロール上の塗料が充分に紙に転写しにくく、ミスト飛散トラブルが発生しやすい。しかしながら本発明のごとく、下塗り塗工層に澱粉又は澱粉誘導体からなる塗工層を設け、かつ、上塗り塗工層の顔料として粒子径の分布において0.1μm以上0.8μm未満の粒子を用いることで、ミスト飛散を防止することができる。より好ましくは、塗料濃度が65質量%以上、好ましくは69質量%以上、特に70質量%以上であれば、更にミスト飛散の発生を防止できるため好ましい。   In particular, when high-speed coating at a coating speed of 1300 m / min or more is performed using a film transfer type roll coater, the paint on the roll surface is difficult to transfer to paper, and the paint that has not been transferred scatters and mist is generated. Mist scattering trouble is likely to occur. In particular, as in the present invention, when a pigment having a small particle diameter is used, the paint on the roll is not easily transferred onto the paper, and mist scattering trouble is likely to occur. However, as in the present invention, a coating layer made of starch or starch derivative is provided in the undercoat coating layer, and particles having a particle size distribution of 0.1 μm or more and less than 0.8 μm are used as the pigment of the topcoat coating layer. Thus, mist scattering can be prevented. More preferably, the coating concentration is 65% by mass or more, preferably 69% by mass or more, and particularly preferably 70% by mass or more because generation of mist scattering can be further prevented.

このような塗料とするには、塗料の構成成分である顔料溶液の濃度が75質量%以上であると、接着剤や助剤等を混合して得られる塗料濃度も高くなり易いため好ましい。一般の塗工紙においては、白紙光沢度を向上させるために、より平板状であり光沢発現性の良好なクレーを用いるが、クレーは炭酸カルシウムと比べて保水性が良いため紙に転写しにくく、ミスト飛散の原因となりやすい。のみならず、クレーは顔料単体の濃度が低いため、塗料濃度が低下しやすく、均一な塗工層を形成しにくいため好ましくない。   In order to obtain such a paint, it is preferable that the concentration of the pigment solution, which is a constituent component of the paint, is 75% by mass or more because the paint concentration obtained by mixing an adhesive, an auxiliary agent, and the like tends to increase. In general coated paper, to improve the glossiness of blank paper, use clay that is more flat and has good glossiness. However, clay has better water retention than calcium carbonate and is difficult to transfer to paper. , Easy to cause mist scattering. In addition, clay is not preferable because the concentration of the pigment alone is low, and thus the coating concentration tends to decrease and it is difficult to form a uniform coating layer.

塗料濃度が上記範囲であれば、ミスト飛散を防止しやすいものの、単に保水剤等の増粘作用を有する助剤を塗料に添加しただけでは、塗料の紙への転写性に劣りミスト飛散を充分に防止できない。ミスト飛散を防止するためには、塗料の濃度を低下させずに粘度を向上させ、紙に転写しやすい塗料とすることが好ましいが、単に保水剤を加えて粘度を向上させた場合は、保水剤が過剰となり白色度、白紙光沢度が劣るだけでなく、ミスト飛散が発生しやすくなるため好ましくなく、逆に保水剤を低減させても塗料粘度が低いため、ミスト飛散を充分に防止しにくいため好ましくない。   If the paint concentration is in the above range, it is easy to prevent mist scattering, but simply adding an auxiliary agent having a thickening action such as a water retention agent is inferior in the transferability of the paint to paper and the mist scattering is sufficient. Cannot be prevented. In order to prevent mist scattering, it is preferable to improve the viscosity without lowering the concentration of the paint and to make the paint easy to transfer to paper. However, if the viscosity is simply improved by adding a water retention agent, Not only is the agent excessive and the whiteness and glossiness of the white paper are inferior, but mist scattering is likely to occur, which is not preferable. Conversely, even if the water retention agent is reduced, the viscosity of the paint is low, so it is difficult to prevent mist scattering sufficiently. Therefore, it is not preferable.

このため、本発明のごとく、顔料及び接着剤からなる塗料を、澱粉又は澱粉誘導体を片面あたり0.5〜1.0g/m下塗り塗工した原紙に塗布する場合は、保水剤の中でも重量平均分子量が500万〜3000万であることが好ましく、700万〜2000万であることが更に好ましい。分子量が500万を下回ると塗料粘度が向上しにくく、配合量が少ない場合と同様にミスト飛散を充分に防止しにくくなる。分子量が3000万を超過すると、B型粘度が向上して耐ブリスター性やミスト飛散が発生しやすくなるだけでなく、塗料の流動性が低下するためポンプ等で輸送することが困難となりやすい。重量平均分子量が500万〜3000万である保水剤としては、例えばソマレックス#500および#530(ソマール社製)が挙げられる。
保水剤の添加量は顔料100質量部に対して0.01〜0.20質量部配合することが好ましく、0.03〜0.15質量部配合することがより好ましい。これにより、塗料濃度は65質量%以上、好ましくは69質量%以上、特に70質量%以上とすることができ、更に高粘度であるためミスト飛散の発生を防止できるため好ましい。濃度が65質量%を下回ると、基紙に塗工液中の水分が吸液されやすく、粒径の小さい顔料が紙内部に吸収されて充分な白紙光沢度が得られにくい。
Therefore, as in the present invention, when a paint comprising a pigment and an adhesive is applied to a base paper coated with 0.5 to 1.0 g / m 2 of starch or starch derivative per side, it is a weight among water retaining agents. The average molecular weight is preferably 5 million to 30 million, more preferably 7 million to 20 million. If the molecular weight is less than 5,000,000, the viscosity of the paint is difficult to improve, and it is difficult to sufficiently prevent mist scattering as in the case where the blending amount is small. When the molecular weight exceeds 30 million, not only B-type viscosity is improved and blister resistance and mist scattering are likely to occur, but also the fluidity of the paint is lowered, so that it is difficult to transport with a pump or the like. Examples of the water retention agent having a weight average molecular weight of 5 million to 30 million include Somalex # 500 and # 530 (manufactured by Somaru).
The addition amount of the water retention agent is preferably 0.01 to 0.20 parts by mass, more preferably 0.03 to 0.15 parts by mass with respect to 100 parts by mass of the pigment. Thereby, the paint concentration can be 65% by mass or more, preferably 69% by mass or more, particularly 70% by mass or more, and since it has a higher viscosity, generation of mist scattering can be prevented, which is preferable. When the concentration is less than 65% by mass, water in the coating liquid is easily absorbed by the base paper, and a pigment having a small particle size is absorbed into the paper, making it difficult to obtain sufficient blank paper gloss.

上述のとおり重量平均分子量が500万〜3000万、好ましくは700万〜2000万の保水剤を用いると、0.01〜0.20質量部と少ない量であっても、例えばB型粘度が600〜1400、好ましくは800〜1200の範囲とすることができ、フィルム転写型ロールコーターを用いた場合において、ロール上に塗膜を均一に形成することができ、均一な塗工層を有する塗工紙が得られるため好ましい。B型粘度が600を下回ると、ロール上に均一な塗膜が得られないため、塗工層に光沢ムラが発生しやすいだけでなく、表面強度が低下しやすいため好ましくない。B型粘度が1400を超過すると、粘性が高すぎてミスト飛散が発生しやすいだけでなく、塗工層が密に詰まり耐ブリスター性に劣るため好ましくない。尚、本発明で言う分子量とは、ゲル浸透クロマトグラフィー法(GPC法)によって測定した重量平均分子量を言う。
また、保水剤の成分としては、一般に製紙用途に使用されるカルボキシメチルセルロースのナトリウム塩(CMC)、ヒドロキシエチルセルロース(HES)等が挙げられるが、好ましくは合成保水剤と呼ばれているアクリル酸系共重合体、特に多価カルボン酸アクリル系共重合体やメタクリル酸とアクリル酸エステルの共重合体、アクリル酸とアクリルアミドの共重合体等であれば、B型粘度を向上させやすいため好ましい。
As described above, when a water retention agent having a weight average molecular weight of 5 million to 30 million, preferably 7 million to 20 million is used, even if the amount is as small as 0.01 to 0.20 parts by mass, for example, the B-type viscosity is 600. -1400, preferably in the range of 800-1200, when a film transfer type roll coater is used, a coating film can be uniformly formed on the roll and has a uniform coating layer This is preferable because paper is obtained. If the B-type viscosity is less than 600, a uniform coating film cannot be obtained on the roll, so that not only gloss unevenness tends to occur in the coating layer but also the surface strength tends to decrease, which is not preferable. When the B-type viscosity exceeds 1400, not only is the viscosity too high and mist scattering tends to occur, but also the coating layer is densely packed and inferior in blister resistance, such being undesirable. In addition, the molecular weight said by this invention means the weight average molecular weight measured by the gel permeation chromatography method (GPC method).
Examples of the water retention component include sodium salt of carboxymethyl cellulose (CMC), hydroxyethyl cellulose (HES) and the like that are generally used for papermaking applications. Preferably, the acrylic acid copolymer is called a synthetic water retention agent. A polymer, particularly a polycarboxylic acid acrylic copolymer, a copolymer of methacrylic acid and an acrylic ester, a copolymer of acrylic acid and acrylamide, and the like are preferable because the B-type viscosity is easily improved.

重量平均分子量が500万〜3000万以外の保水剤としては、一般に製紙用途に用いられているものを挙げることができるが、上述のごとく、塗料の濃度及び粘度を同時に向上できず、例えばフィルム転写型ロールコーターを用いて、1300m/分以上の速度で塗工すると、ミストが飛散しやすいだけでなく、B型粘度が向上しにくくロール上に塗料の塗膜を形成しにくく、均一な塗工層が得られないため好ましくない。分子量が500万未満または3000万を超過する保水剤も高い保水力を有しているが、0.01〜0.20質量部と少ない配合量では塗料の粘度が低く均一な塗膜を形成しにくく、均一な塗工層が得られにくい。保水剤の配合量を0.20質量部以上に増加させていくと、粘度が頭打ちになる一方、濃度が低下するため、塗料中の水分が基紙へ沈み込むにつれて、小粒子の顔料が基紙中に入り込みやすくなり、白紙光沢度や表面強度に劣るだけでなく、ミスト飛散が増加するため好ましくない。   Examples of water retention agents having a weight average molecular weight other than 5 million to 30 million include those generally used for papermaking, but as described above, the concentration and viscosity of the paint cannot be improved at the same time. For example, film transfer When coating at a speed of 1300 m / min or more using a mold roll coater, not only the mist is likely to be scattered, but also the B-type viscosity is difficult to improve, and it is difficult to form a paint film on the roll. Since a layer cannot be obtained, it is not preferable. Water retention agents with a molecular weight of less than 5 million or over 30 million also have high water retention, but with a small blending amount of 0.01 to 0.20 parts by mass, a uniform coating film is formed with a low viscosity of the paint. It is difficult to obtain a uniform coating layer. When the blending amount of the water retention agent is increased to 0.20 part by mass or more, the viscosity reaches a peak, while the concentration decreases. Therefore, as the moisture in the paint sinks into the base paper, the small particle pigment becomes the basis. This is not preferable because it easily penetrates into the paper, is not only inferior in white paper glossiness and surface strength, but also increases in mist scattering.

上述のごとく、澱粉又は澱粉誘導体を片面あたり0.5〜1.0g/m下塗り塗工した原紙に、粒子径の分布において0.1μm以上0.8μm未満の粒子を顔料として用い、ブタジエン成分を40〜65質量%、スチレン成分を10〜35質量%含むラテックスからなる塗料を、フィルム転写型ロールコーターを用いて、1300m/分以上の速度で塗工する場合は、重量平均分子量が500万〜3000万の保水剤を、顔料100質量部に対して0.01〜0.20質量部配合し、塗料濃度は65質量%以上、好ましくは69質量%以上、特に70質量%以上とし、B型粘度が600〜1400、好ましくは800〜1200の範囲に調整することで、ミストの発生を抑制しつつ、高い白紙光沢度、表面強度を有し、耐ブリスター性に優れる塗工紙を、生産性良く得ることができる。 As described above, a butadiene component using particles having a particle size distribution of 0.1 μm or more and less than 0.8 μm as a pigment on a base paper coated with 0.5 to 1.0 g / m 2 of starch or starch derivative per side. In the case where a paint comprising latex containing 40 to 65% by mass and 10 to 35% by mass of a styrene component is applied at a speed of 1300 m / min or more using a film transfer type roll coater, the weight average molecular weight is 5 million. ~ 30 million water retention agent is blended in an amount of 0.01 to 0.20 parts by mass with respect to 100 parts by mass of the pigment, and the coating concentration is 65% by mass or more, preferably 69% by mass or more, and particularly 70% by mass or more. By adjusting the mold viscosity to a range of 600 to 1400, preferably 800 to 1200, it has high blank paper gloss and surface strength while suppressing the occurrence of mist, and is blister resistant. Coated paper that can be obtained with good productivity.

塗工液を調製する方法には特に限定がなく、顔料、接着剤や、必要に応じて各種助剤等の配合割合を調整し、適切な温度にて均一な組成となるように撹拌混合すればよい。また塗工液の濃度は特に限定されず、顔料塗工層の塗工量が好ましくは片面あたり5〜15g/m、より好ましくは6〜8g/mの範囲となるように調整すれば良い。例えば、濃度が65質量%以上であれば良く、69質量%が更に好ましく、70質量%以上が最も好ましい。 There is no particular limitation on the method for preparing the coating liquid, and the mixing ratio of pigments, adhesives, and various auxiliary agents as necessary may be adjusted and stirred and mixed so as to obtain a uniform composition at an appropriate temperature. That's fine. The concentration of the coating solution is not particularly limited, and the coating amount of the pigment coating layer is preferably 5 to 15 g / m 2 per side, more preferably 6 to 8 g / m 2. good. For example, the concentration may be 65% by mass or more, more preferably 69% by mass, and most preferably 70% by mass or more.

本実施形態にて用いる塗工液には、顔料及び接着剤以外にも、例えば、ダスト防止剤、蛍光染料、蛍光染料増白剤、消泡剤、離型剤、着色剤等、製紙用途で一般に用いられる各種助剤を、本発明の目的を阻害しない範囲で配合することができる。   In addition to pigments and adhesives, the coating liquid used in the present embodiment includes, for example, dust prevention agents, fluorescent dyes, fluorescent dye brighteners, antifoaming agents, mold release agents, colorants, and the like for papermaking applications. Various commonly used auxiliaries can be blended within a range that does not impair the object of the present invention.

上塗り塗工層は、塗工量が固形分付着量で片面あたり、好ましくは5〜15g/m、より好ましくは6〜8g/mとなるように塗工される。固形分付着量が5g/m未満であると均一な塗工性や十分な被覆性が得られにくく、白紙光沢度が低下しやすい問題がある。塗工量が15g/mを超えると、塗工層が厚くなり耐ブリスター性に劣るだけでなく、フィルム転写型ロールコーターにおいては、塗膜全量が紙に転写しにくくなり、余剰の塗膜がミストとなって飛散する可能性があるため好ましくない。 The topcoat coating layer is applied so that the coating amount is a solid content adhesion amount per side, preferably 5 to 15 g / m 2 , more preferably 6 to 8 g / m 2 . When the solid content adhesion amount is less than 5 g / m 2 , there is a problem that uniform coatability and sufficient coverage are difficult to be obtained, and the glossiness of the white paper tends to be lowered. When the coating amount exceeds 15 g / m 2 , the coating layer becomes thick and inferior in blister resistance, and in the film transfer type roll coater, it becomes difficult to transfer the entire coating film to the paper, and the excess coating film Is not preferable because it may be scattered as mist.

(平坦化処理)
前記のごとく形成された塗工層には、印刷適性をさらに向上させる目的で、スーパーカレンダーやソフトカレンダー等、弾性ロールと金属ロールとを組み合わせた平坦化設備にて平坦化処理を施すことができる。このような平坦化設備は、従来のマシンカレンダーとは異なり、用紙表面を幅広の面で、高温で処理することで、塗工層の繊維焼けを防止し、高い白色度のままで平坦化させ高い白紙光沢度を得ることが可能であり、例えばオフセット印刷、電子写真印刷等において好適な印刷面を形成させることができる。中でも、マルチニップカレンダー、より望ましくは6段、8段、10段のマルチニップカレンダーが、ニップ圧を調整しやいため好ましい。特に、塗工層に炭酸カルシウムを用いる場合、カオリンクレーに比べて白紙光沢度が得られにくいため、線圧を調整できるマルチニップカレンダーを用いると、他のカレンダー設備に比して、より高い白色度を維持しつつ白紙光沢度を向上させやすいため、特に好ましい。
(Flattening process)
For the purpose of further improving the printability, the coating layer formed as described above can be subjected to a flattening process using a flattening facility that combines an elastic roll and a metal roll, such as a super calender or a soft calender. . Unlike conventional machine calenders, such flattening equipment treats the paper surface with a wide surface at a high temperature to prevent fiber burn of the coating layer and to flatten it with high whiteness. High white paper glossiness can be obtained, and a suitable printing surface can be formed in, for example, offset printing, electrophotographic printing, and the like. Among them, a multi-nip calender, more preferably a 6-stage, 8-stage, or 10-stage multi-nip calender is preferable because the nip pressure can be easily adjusted. In particular, when calcium carbonate is used for the coating layer, it is difficult to obtain white paper gloss compared to kaolin clay, so if you use a multi-nip calender that can adjust the linear pressure, it will be whiter than other calender equipment This is particularly preferable because it easily improves the glossiness of the white paper while maintaining the degree.

また、カレンダーの設置場所としては、抄紙機及び塗工機と一体になったオンマシンタイプが好ましい。オンマシンタイプでは、塗工後すぐ、紙面温度が高い状態で平坦化処理できるため、より白紙光沢度が向上しやすく、繊維焼け等の白色度の低下を伴わずに、高い白紙光沢度が得られるため好ましい。   Moreover, as an installation place of a calendar, an on-machine type integrated with a paper machine and a coating machine is preferable. With the on-machine type, flattening can be performed immediately after coating with the paper surface at a high temperature, making it easier to improve white paper gloss, and high white paper gloss can be obtained without decreasing whiteness such as fiber burn. Therefore, it is preferable.

各種カレンダー設備を用いた平坦化処理の線圧や温度、速度は特に限定されないが、処理後の塗工層の平滑性を充分に向上させつつ、手肉感が良好となるには、例えば線圧は100〜300kN/m、金属ロール温度は100〜200℃、速度は1,000〜2,000m/分となるように調整することが好ましい。   The linear pressure, temperature, and speed of the flattening treatment using various calendar facilities are not particularly limited. To improve the smoothness of the coated layer after the treatment and improve the hand feeling, for example, the linear pressure is 100. It is preferable to adjust so that it may become -300 kN / m, a metal roll temperature may be 100-200 degreeC, and a speed | rate may be 1,000-2,000 m / min.

かくして得られる塗工紙の坪量は、印刷適性、手肉感の確保という点から、JISP8124「坪量測定方法」に記載の方法に準拠して測定して、40〜100g/mであることが好ましく、さらには50g/m〜80g/mであることが好ましい。坪量が40g/m未満の場合、例えば白色度、白紙光沢度を確保しながら、同時に印刷に耐ええる紙質強度を確保することが困難となる恐れがあり、坪量が100g/mを超える場合には、近年要求されてきている軽量化や省資源化を達成することが困難となる恐れがある。 The basis weight of the coated paper thus obtained is 40 to 100 g / m 2 as measured in accordance with the method described in JISP 8124 “Basis weight measurement method” from the viewpoint of ensuring printability and hand feeling. preferably, it is preferred that even at 50g / m 2 ~80g / m 2 . When the basis weight is less than 40 g / m 2 , for example, it may be difficult to secure the paper strength sufficient to withstand printing while securing the whiteness and white paper gloss, and the basis weight is 100 g / m 2 . In the case of exceeding the above, it may be difficult to achieve the weight reduction and resource saving that have been required in recent years.

次に、本発明の塗工紙を以下の実施例に基づいてさらに詳細に説明するが、本発明はこれらの実施例のみに限定されるものではない。
実施例及び比較例
表1に示す種類及び割合で、下塗り塗工及び上塗り塗工を行い、塗工紙を得た。用いた顔料、原料および薬品は以下のとおりである。
Next, although the coated paper of this invention is demonstrated still in detail based on the following examples, this invention is not limited only to these Examples.
Examples and Comparative Examples Undercoat coating and topcoating were carried out in the types and proportions shown in Table 1 to obtain coated paper. The pigments, raw materials and chemicals used are as follows.

(1)下塗り塗工
下塗り塗工層に次の薬品を用いた。
・酸化澱粉(変性酸化澱粉、加藤化学社製、実施例1〜53,比較例5〜8)
・PVA(ポリビニルアルコール、品番:PVA−110、クラレ社製、比較例3)
・リン酸(リン酸エステル化澱粉、品番:MS4600、日本食品加工社製、比較例4)
尚、比較例1では下塗り塗工層を設けず、比較例2では次に述べる上塗り塗工の塗料のうち、実施例1と同じものを片面あたり3g/m塗布して下塗り顔料塗工層を設けた。
(1) Undercoat coating The following chemicals were used in the undercoat coating layer.
・ Oxidized starch (modified oxide starch, manufactured by Kato Chemical Co., Examples 1 to 53, Comparative Examples 5 to 8)
-PVA (polyvinyl alcohol, product number: PVA-110, manufactured by Kuraray Co., Ltd., Comparative Example 3)
Phosphoric acid (phosphate esterified starch, product number: MS4600, manufactured by Nippon Food Processing Co., Ltd., Comparative Example 4)
In Comparative Example 1, an undercoat coating layer was not provided. In Comparative Example 2, the same coating as in Example 1 was applied at 3 g / m 2 per side among the topcoat coating materials described below, and an undercoat pigment coating layer was applied. Was provided.

(2)上塗り塗工
(顔料)
・炭酸カルシウム
微粒炭カル:微粒重質炭酸カルシウム(品番:カービラックス、イメリス ミネラルズ・ジャパン社製、平均粒子径:0.9μm)
比較例8以外では、微粒重質炭酸カルシウムの粉砕の程度を調整して製造した。
重質炭カル:重質炭酸カルシウム(品番:ハイドロカーブ90、オミヤコーリア社製、平均粒子径:1.0μm)
重質炭カルは、重質炭酸カルシウムの粉砕の程度を調整して製造した。
毬栗炭カル:毬栗状軽質炭酸カルシウム(品番:ベルカーブ、スペシャリティミネラルズ社製、平均粒子径:1.5μm)
・クレー:(品番:アマゾンプラス、カデム社製、平均粒子径:0.5μm)
・再生粒子凝集体
再生粒子A:特許第3869455号公報の製法に準じて粒径を調整して製造した。具体的には、古紙の処理工程から排出される脱墨フロスを水分率60%まで脱水し(脱水工程)、120℃で乾燥して(乾燥工程)焼成工程入口での水分率が3%になるようにし、第1焼成工程で未燃分が7%となるように550℃で焼成し、第2焼成工程で未燃分が12質量%となるように焼成し(焼成工程)、粒子径500μmの再生粒子凝集体を製造した。
再生粒子B:第1焼成工程で400℃で焼成した以外は、再生粒子Aと同様に製造した再生粒子凝集体を使用した。
重質炭酸カルシウム、再生粒子凝集体は、湿式粉砕機(品番:プラネタリーミル、セイシン企業製)を用いて粉砕し、粒子径の分布において、表に記載の極大値を有する顔料に調製し使用した。
(2) Top coating (pigment)
・ Calcium carbonate Fine coal cal: Fine heavy calcium carbonate (Product number: Carbillax, Imeris Minerals Japan, average particle size: 0.9 μm)
Except for Comparative Example 8, it was produced by adjusting the degree of pulverization of fine heavy calcium carbonate.
Heavy coal cal: Heavy calcium carbonate (Product number: Hydro curve 90, manufactured by Omiya Korea, average particle size: 1.0 μm)
Heavy coal cal was produced by adjusting the degree of pulverization of heavy calcium carbonate.
Chestnut charcoal Calm: Chestnut-like light calcium carbonate (Product No .: Bell curve, manufactured by Specialty Minerals, average particle size: 1.5 μm)
・ Clay: (Product number: Amazon plus, manufactured by Kadem, average particle size: 0.5 μm)
-Regenerated particle aggregate Regenerated particle A: manufactured by adjusting the particle diameter according to the production method of Japanese Patent No. 3869455. Specifically, the deinking floss discharged from the waste paper treatment process is dehydrated to a moisture content of 60% (dehydration process), dried at 120 ° C. (drying process), and the moisture content at the firing process inlet becomes 3%. And firing at 550 ° C. so that the unburned portion becomes 7% in the first firing step, and firing so that the unburned portion becomes 12 mass% in the second firing step (baking step), and the particle size A 500 μm regenerated particle agglomerate was produced.
Regenerated particles B: Regenerated particle aggregates produced in the same manner as the regenerated particles A were used except that they were fired at 400 ° C. in the first firing step.
Heavy calcium carbonate and regenerated particle agglomerates are pulverized using a wet pulverizer (product number: planetary mill, manufactured by Seishin Enterprise Co., Ltd.), and prepared and used as a pigment having the maximum value shown in the table in the particle size distribution did.

尚、本発明の粒子径は次のように測定した。塗工紙をA4サイズに切り出し、用紙短辺を上辺として、上辺から下にAcm、左辺からAcmの地点で、縦横5mm角のサンプルを切り出した。ここでAは1〜20の整数であり、合計20サンプルを採取した。切り出したサンプルの表面を、走査電子顕微鏡(型番:S−2150、(株)日立製作所製)を用いて倍率12000倍で写真撮影した。写真の上辺から下にBcm、左辺からBcmの地点に最も近く、かつ粒子全体が撮影されている顔料について、粒子径を測定した。ここでBは1〜5の整数であり、1サンプルから5個の粒子の粒子径を求め、合計100点の顔料粒子について粒子径を求めた。顔料粒子は真円ではないため、顔料粒子を内包できる最小の円の直径を粒子径とした。   The particle diameter of the present invention was measured as follows. The coated paper was cut out to A4 size, and a sample of 5 mm square was cut out at a point of Acm from the upper side to the lower side and Acm from the left side, with the short side of the paper as the upper side. Here, A is an integer of 1 to 20, and a total of 20 samples were collected. The surface of the cut out sample was photographed at a magnification of 12000 using a scanning electron microscope (model number: S-2150, manufactured by Hitachi, Ltd.). The particle diameter was measured for the pigment that was closest to the point Bcm from the top side of the photograph and Bcm from the left side, and the entire particle was photographed. Here, B is an integer of 1 to 5, the particle diameter of 5 particles was determined from one sample, and the particle diameter was determined for a total of 100 pigment particles. Since the pigment particles are not perfect circles, the diameter of the smallest circle that can contain the pigment particles is taken as the particle diameter.

顔料の平均粒子径は、当該顔料を単体で使用した以外は実施例1と同様に塗工紙を製造し、上述の方法で100点の粒子径を測定し、その中央値とした。   The average particle diameter of the pigment was the median value obtained by producing a coated paper in the same manner as in Example 1 except that the pigment was used alone and measuring the particle diameter at 100 points by the method described above.

顔料の粒子径の分布は、粒子の数を粒子径0.1μmごとに集計して粒子径の分布を求めた。この0.1μmごとに分類した顔料集団について、極大値の有無を判断した。   The particle size distribution of the pigment was determined by counting the number of particles every 0.1 μm particle size. For the pigment group classified every 0.1 μm, the presence or absence of a maximum value was determined.

(接着剤)
スチレン−ブタジエン共重合体ラテックス(品番:PA−4098、日本A&L社製、傾斜型)
スターチ(酸化澱粉、品番:オキセル、三晶社製)
但し、実施例27〜30は、表に記載の成分割合となるよう調整した。表に記載したラテックス成分の略号は次のとおり。ST:スチレン、BD:ブタジエン、MMA:メタクリル酸メチル、AN:アクリロニトリル。
(adhesive)
Styrene-butadiene copolymer latex (Part No .: PA-4098, manufactured by Japan A & L, Inc.)
Starch (oxidized starch, product number: Oxel, manufactured by Sankisha)
However, Examples 27 to 30 were adjusted to have the component ratios described in the table. Abbreviations for latex components listed in the table are as follows. ST: Styrene, BD: Butadiene, MMA: Methyl methacrylate, AN: Acrylonitrile.

(保水剤)
♯530(重量平均分子量1000万、品番:ソマレックス530、ソマール社製)実施例40〜45は、表に記載のとおり重量平均分子量を調整した保水剤を使用した。
♯270K(重量平均分子量200万、品番:ソマレックス270K、ソマール社製)
(Water retention agent)
# 530 (weight average molecular weight 10 million, product number: Somalex 530, manufactured by Somaru) Examples 40 to 45 used water retention agents whose weight average molecular weight was adjusted as shown in the table.
# 270K (weight average molecular weight 2 million, product number: Somalex 270K, manufactured by Somare)

(製造手順)
原料パルプとしてLBKPとNBKPを80:20の質量割合で配合し、このパルプ(絶乾量)に対して、各々固形分で、填料(軽質炭酸カルシウム、品番:TP121―6S、奥多摩工業社製)10質量%、内添サイズ剤(品番:AK−720H、ハリマ化成(株)製)0.02質量%、カチオン化澱粉(品番:アミロファックスT−2600、アベベジャパン(株)製)1.0質量%、及び歩留向上剤(品番:NP442、日産エカケミカルス(株)製)0.02質量%を添加してパルプスラリーを得た。
(Manufacturing procedure)
LBKP and NBKP are blended at a mass ratio of 80:20 as raw material pulp, and the filler (light calcium carbonate, product number: TP121-6S, manufactured by Okutama Kogyo Co., Ltd.) is solid for each pulp (absolute dry amount). 10% by mass, internal sizing agent (product number: AK-720H, manufactured by Harima Chemicals Co., Ltd.) 0.02% by mass, cationized starch (product number: amylofax T-2600, manufactured by Abebe Japan Co., Ltd.) 1.0 A pulp slurry was obtained by adding 0.02% by mass and a yield improver (product number: NP442, manufactured by Nissan Eka Chemicals Co., Ltd.).

次に、ワイヤーパート、プレスパート、プレドライヤーパート、コーターパート、スキャッフドライヤーパート、カレンダーパート、リールパートを含む製紙システムを用いワインダーパートにて製品に仕上げた。   Next, the product was finished in a winder part using a papermaking system including a wire part, a press part, a pre-dryer part, a coater part, a scuff dryer part, a calendar part, and a reel part.

まず、パルプスラリーをワイヤーパートにて抄紙し、次いでプレスパート、プレドライヤーパートに供して、坪量26〜52g/mの基紙を製造し、次いでコーターパートにて、澱粉又は澱粉誘導体からなる塗料を、表1に記載の量のとおりフィルム転写型ロールコーターを用いて下塗り塗工し、乾燥後、プレカレンダーパートで、線圧20kN/mの線圧で平坦化処理を行った後、顔料として表1に記載の顔料及び、顔料100質量部に対して表に記載のとおりの部数でラテックス及びスターチ、保水剤を混合して、濃度71質量%および表1に記載の粘度に調製した塗工液を、片面あたり表1に記載のとおり、フィルム転写型ロールコーターで両面を塗工し、坪量62g/mの印刷用塗工紙を製造した。 First, the pulp slurry is made with a wire part, then subjected to a press part and a pre-dryer part to produce a base paper having a basis weight of 26 to 52 g / m 2 , and then made of starch or a starch derivative at a coater part. The paint is undercoated using a film transfer type roll coater as shown in Table 1. After drying, the pre-calender part is subjected to a flattening treatment at a linear pressure of 20 kN / m, and then the pigment. As a coating solution prepared by mixing latex, starch and water retention agent in the number of parts described in the table with respect to the pigment described in Table 1 and 100 parts by mass of the pigment, the concentration is 71% by mass and the viscosity is described in Table 1. As shown in Table 1 per side, the working solution was coated on both sides with a film transfer type roll coater to produce a coated paper for printing having a basis weight of 62 g / m 2 .

次に、カレンダーパートにて、線圧200kN/m、速度1,000m/分で平坦化処理を施し、ワインダーパートに供して印刷用塗工紙を得た。   Next, the calender part was subjected to a flattening treatment at a linear pressure of 200 kN / m and a speed of 1,000 m / min, and was applied to a winder part to obtain a coated paper for printing.

なお、ワイヤーパートではギャップフォーマーを用いて抄紙し、コーターパートではロッドメタリングサイズプレスコーターを用い、カレンダーパートでは、マルチニップカレンダーを用いた。   The wire part was made using a gap former, the coater part was a rod metering size press coater, and the calendar part was a multi-nip calender.

得られた塗工紙は、上述のとおり、0.1μmごとに集計した粒子径の分布において、表に記載の範囲に極大値を有するか否かを測定した。   As described above, the obtained coated paper was measured for whether or not it had a maximum value in the range shown in the table in the distribution of particle diameters counted every 0.1 μm.

尚、濃度およびB型粘度は次のとおり求めた。
濃度:塗料10gを量り取り、温度105℃で8時間乾燥させ、水分を除去した後の固形分含有量(質量%)を濃度とした。
B型粘度:東機産業社製のB型粘度計を用い、No.3のボブで、毎分60回転における粘度をB型粘度(mPa・s)とした。
The concentration and B type viscosity were determined as follows.
Concentration: 10 g of paint was weighed and dried at a temperature of 105 ° C. for 8 hours to remove the moisture, and the solid content (mass%) was taken as the concentration.
B-type viscosity: A B-type viscometer manufactured by Toki Sangyo Co., Ltd. With the bob of 3, the viscosity at 60 revolutions per minute was defined as the B-type viscosity (mPa · s).

得られた塗工紙について、以下の項目を評価した。その結果を表に示す。
(a)白色度
JISP8148:2001「紙、板紙及びパルプ−ISO白色度(拡散青色反射率)の測定方法」に記載の方法に準じて、未印刷の塗工紙について測定した。尚、白色度は77%以上であれば実使用に問題なく、80%以上であれば見栄えに優れ、83%以上であれば、特に印刷光沢に優れた塗工紙となる。
The following items were evaluated about the obtained coated paper. The results are shown in the table.
(A) Whiteness It measured about the unprinted coated paper according to the method of JISP8148: 2001 "Paper, paperboard, and a pulp-ISO whiteness (diffuse blue reflectance) measuring method". If the whiteness is 77% or more, there is no problem in actual use, and if it is 80% or more, the appearance is excellent, and if it is 83% or more, the coated paper is particularly excellent in printing gloss.

(b)白紙光沢度
JISP8142:2005「紙及び板紙−75度鏡面光沢度の測定方法」に記載の方法に準じて、未印刷の塗工紙について測定した。尚、白色光沢度は35%以上であれば実使用に問題なく、40%以上であれば見栄えに優れ、45%以上であれば、特に白紙光沢に優れた塗工紙となる。
(B) White Paper Glossiness JISP8142: 2005 was measured for unprinted coated paper according to the method described in “Paper and paperboard—Method for measuring 75 ° specular gloss”. If the white glossiness is 35% or more, there is no problem in actual use. If it is 40% or more, the appearance is excellent, and if it is 45% or more, the coated paper is particularly excellent in white paper gloss.

(c)不透明度
JISP8149:2000「紙及び板紙−不透明度試験方法(紙の裏当て)−拡散照明法」に記載の方法に準じて、未印刷の塗工紙について測定した。尚、不透明度は78%以上であれば実使用に問題なく、84%以上であれば見栄えに優れ、90%以上であれば、特に不透明度に優れた塗工紙となる。
(C) Opacity JISP8149: 2000 It measured about the unprinted coated paper according to the method as described in "Paper and board-Opacity test method (backing of paper)-diffuse illumination method". If the opacity is 78% or more, there is no problem in actual use, and if it is 84% or more, the appearance is excellent, and if it is 90% or more, the coated paper is particularly excellent in opacity.

・オフセット印刷サンプルの調製
オフセット印刷機(型番:LITHOPIA MAX BT2−1000、三菱重工業(株)製)を使用し、カラーインク(品番:ADVAN、大日本インキ化学工業(株)製)にて、B4折のカラー4色印刷を、速度1,200rpmで5000部印刷した。紙面温度は115℃に設定した。
-Preparation of offset printing sample Using an offset printing machine (model number: LITHOPIA MAX BT2-1000, manufactured by Mitsubishi Heavy Industries, Ltd.), color ink (part number: ADVAN, manufactured by Dainippon Ink & Chemicals, Inc.), B4 Folded four color prints were printed at 5000 speeds at 1,200 rpm. The paper surface temperature was set to 115 ° C.

(d)表面強度
次の条件で塗工紙にRI印刷を行ってRI印刷試験体を作製した。
・印刷機:RI‐3型、(株)明製作所製
・インキ:WebRexNouverHIMARKプロセス(藍)、大日精化社製
・インキ量:上段ロールに0.3ml、下段ロールに0.2ml
・試験方法:上段、下段ロールでそれぞれインキを各3分間練り(2分間練った後、ロールを反転させてさらに1分間練る)、回転速度30rpmで2色同時印刷を行った。
前記RI印刷試験体について、白抜けの発生度合いを目視及びルーペ(10倍)にて観察し、以下の評価基準に基づいて評価した。
(評価基準)
◎:目視及びルーペで確認して白抜けがなく、印刷品質に特に優れる。
○:ルーペでは白抜けの発生が僅かに認められるが、目視では白抜けが認められず、印刷品質に優れる。
△:ルーペでは白抜けの発生が多少認められ、目視でも白抜けが僅かに認められ、印刷品質が良好である。
×:目視及びルーペで確認して白抜けが容易に認められ、印刷品質に劣る。
なお、前記評価基準のうち、◎、○、△を実使用可能と判断する。
(D) Surface strength RI printing was performed on the coated paper under the following conditions to prepare an RI printing test specimen.
・ Printing machine: RI-3 type, manufactured by Akira Seisakusho Co., Ltd. ・ Ink: WebRexNouverHIMARK process (indigo), manufactured by Dainichi Seika Co., Ltd. ・ Ink amount: 0.3 ml for the upper roll and 0.2 ml for the lower roll
Test method: The ink was kneaded for 3 minutes each with the upper and lower rolls (kneaded for 2 minutes, then the roll was inverted and further kneaded for 1 minute), and two-color simultaneous printing was performed at a rotation speed of 30 rpm.
About the said RI printing test body, the generation | occurrence | production degree of white spot was observed visually and with a magnifier (10 times), and it evaluated based on the following evaluation criteria.
(Evaluation criteria)
A: There is no white spot as confirmed visually or with a loupe, and the print quality is particularly excellent.
○: Slight occurrence of white spots is observed in the loupe, but white spots are not visually recognized, and the print quality is excellent.
Δ: Some occurrence of white spots was observed in the loupe, slight white spots were visually observed, and the print quality was good.
X: White spots are easily recognized visually and visually confirmed with a magnifying glass, resulting in poor print quality.
Of the evaluation criteria, ◎, ○, and Δ are determined to be actually usable.

(e)耐ブリスター
印刷用塗工紙の試験サンプル(流れ方向2cm、幅方向10cm)を23℃、50%RH条件下で24時間調湿したのち、一定温度に調整したオイルバス(シリコンオイル)に4秒間浸けた。この試験を3回行い、ブリスターが発生した温度のうち、最も低い温度をブリスター発生温度とした。なお、オイルバスの温度は、160℃から10℃刻みで昇温させ、その温度においてブリスターが発生した場合に、ブリスター発生温度とした。尚、ブリスター発生温度は180℃以上であれば耐ブリスター性が良好であり、190℃以上であれば耐ブリスター性に優れ、200℃以上であれば特に耐ブリスター性に優れる塗工紙となる。
(E) Anti-blister oil bath (silicon oil) adjusted to a constant temperature after conditioning a test sample of coated paper for printing (flow direction 2 cm, width direction 10 cm) under conditions of 23 ° C. and 50% RH for 24 hours Soaked for 4 seconds. This test was performed three times, and the lowest temperature among the temperatures at which blisters were generated was defined as the blister generation temperature. The temperature of the oil bath was increased from 160 ° C. in 10 ° C. increments, and when blisters were generated at that temperature, the blister generation temperature was determined. If the blister generation temperature is 180 ° C. or higher, the blister resistance is good, if it is 190 ° C. or higher, the blister resistance is excellent, and if it is 200 ° C. or higher, the coated paper is particularly excellent in blister resistance.

(f)ミスト飛散
上塗り塗工時のミスト飛散の程度を、以下の基準に基づき目視評価した。
◎:ミストの発生が無く、優れた塗工性を有し、実使用上問題ない。
○:ミストが僅かに発生したが、良好な塗工性を有し、実使用上問題ない。
△:ミストが多少発生したが、塗料粕が発生する程度ではなく、実使用上問題ない。
×:ミストにより塗料粕が発生し、塗工紙中に異物として混入し、実使用不可。
(F) Mist scattering The degree of mist scattering during top coating was visually evaluated based on the following criteria.
(Double-circle): There is no generation | occurrence | production of mist, it has excellent coating property, and there is no problem in practical use.
○: Slight mist was generated, but it had good coatability and no problem in actual use.
Δ: Some mist was generated, but not so much that paint flaws were generated, and there was no problem in actual use.
X: Paint mist is generated by mist and mixed as a foreign substance in the coated paper.

Figure 2010242231
Figure 2010242231

本発明の塗工紙は、オフセット印刷で使用される印刷用塗工紙として好適に使用することができる。   The coated paper of the present invention can be suitably used as a printing coated paper used in offset printing.

10 原料
12 貯槽
14 第1燃焼炉
15 装入機
16 排ガスチャンバー
18 排出チャンバー
20 熱風発生炉
20A バーナー
22 再燃焼室
24 予冷器
26 熱交換器
28 誘引ファン
30 煙突
32 第2燃焼炉
34 冷却機
36 粒径選別機
38 燃焼品サイロ
DESCRIPTION OF SYMBOLS 10 Raw material 12 Storage tank 14 1st combustion furnace 15 Charger 16 Exhaust gas chamber 18 Exhaust chamber 20 Hot air generating furnace 20A Burner 22 Recombustion chamber 24 Precooler 26 Heat exchanger 28 Induction fan 30 Chimney 32 Second combustion furnace 34 Cooler 36 Particle size sorter 38 Combustion product silo

Claims (5)

基紙上に、澱粉または澱粉誘導体を主成分とする下塗り塗工層が片面あたり0.5〜1.0g/mの塗工量で設けられ、前記下塗り塗工層上に顔料及び接着剤を主成分とする上塗り塗工層が設けられ、前記顔料が、0.1μmごとに集計した粒子径の分布において、次の(A)の範囲に少なくとも1つの極大値を有する粒子径分布を持つことを特徴とする、塗工紙。
(A)0.1μm以上0.8μm未満
On the base paper, an undercoat coating layer mainly composed of starch or starch derivative is provided at a coating amount of 0.5 to 1.0 g / m 2 per side, and a pigment and an adhesive are placed on the undercoat coating layer. A topcoat coating layer as a main component is provided, and the pigment has a particle size distribution having at least one maximum value in the following range (A) in the particle size distribution aggregated every 0.1 μm. Coated paper characterized by
(A) 0.1 μm or more and less than 0.8 μm
前記顔料が、0.1μmごとに集計した粒子径の分布において、次の(B)の範囲にも極大値を有する粒子径分布を持つことを特徴とする、請求項1に記載の塗工紙。
(B)0.8μm以上2.0μm未満
2. The coated paper according to claim 1, wherein the pigment has a particle size distribution having a maximum value in the following range (B) in a particle size distribution aggregated every 0.1 μm. .
(B) 0.8 μm or more and less than 2.0 μm
前記顔料が、0.1μmごとに集計した粒子径の分布において、前記(A)の範囲に少なくとも2つの極大値を有し、かつ次の(C)および(D)の範囲にそれぞれ少なくとも1つの極大値を有する粒子径分布を持つことを特徴とする、請求項1又は2に記載の塗工紙。
(C)0.5μm以上0.8μm未満
(D)0.1μm以上0.5μm未満
The pigment has at least two maximum values in the range of (A) in the particle size distribution aggregated every 0.1 μm, and at least one of each in the following ranges (C) and (D): The coated paper according to claim 1, wherein the coated paper has a particle size distribution having a maximum value.
(C) 0.5 μm or more and less than 0.8 μm (D) 0.1 μm or more and less than 0.5 μm
前記顔料のうち、70〜95質量%が炭酸カルシウムであり、5〜30質量%が再生粒子凝集体であることを特徴とする、請求項1〜3いずれか1項に記載の塗工紙。   The coated paper according to any one of claims 1 to 3, wherein 70 to 95 mass% of the pigment is calcium carbonate and 5 to 30 mass% is a regenerated particle aggregate. 基紙上に、澱粉または澱粉誘導体を主成分とする下塗り塗工層を片面あたり0.5〜1.0g/m設ける工程と、前記下塗り塗工層上に顔料及び接着剤を主成分とする上塗り塗工層を設ける工程とを含む、塗工紙の製造方法であって、
前記顔料が、0.1μmごとに集計した粒子径の分布において、次の(A)の範囲に極大値を有する粒子径分布を持つことを特徴とする、塗工紙の製造方法。
(A)0.1μm以上0.8μm未満
On the base paper, a step of providing an undercoat coating layer containing starch or starch derivative as a main component in an amount of 0.5 to 1.0 g / m 2 per side, and a pigment and an adhesive as main components on the undercoat coating layer. Including a step of providing a topcoat coating layer,
The method for producing a coated paper, wherein the pigment has a particle size distribution having a maximum value in the following range (A) in the particle size distribution aggregated every 0.1 μm.
(A) 0.1 μm or more and less than 0.8 μm
JP2009088992A 2009-04-01 2009-04-01 Coated paper Pending JP2010242231A (en)

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JP2018062715A (en) * 2016-10-11 2018-04-19 大王製紙株式会社 Print paper and method for manufacturing the same
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