JP4184848B2 - Dustless paper - Google Patents
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【０００１】
【発明の属する技術分野】
本発明は、クリーンルーム等で好適に用いられる無塵紙に関し、更に詳細には、発塵性が低く且つ製造時の作業性にも優れた無塵紙に関する。
【０００２】
【従来の技術】
超ＬＳＩをはじめとする半導体などのエレクトロニクス産業、医薬品や商品の製造業、及び精密機械工業などの先端産業においては、塵埃などによって製品の欠陥や品質、歩留まりなどに重大な悪影響が生じる。そのため、これらの産業における製造ラインは、塵埃のないクリーンルーム内におかれ、該クリーンルーム内の塵埃のない環境で各種の作業が行われている。
そして、クリーンルームにおいては、塵埃の内部への搬入を極力防止することは当然であるが、それと同時に内部での作業に伴う塵埃の発生を極力抑制することが必要とされる。
【０００３】
その一つとしてクリーンルーム内で行われる各種作業のうち、クリーンルーム内での各種作業に伴う記録やコピーの作成、伝票などの作成などにおいて、塵埃の発生を押さえるために無塵紙が使用されている。
このような無塵紙としては、ポリプロピレン樹脂や不織布をベースに作成された合成紙タイプ、及び天然パルプを主体とした原紙にバインダー樹脂を含浸させた含浸紙タイプとがある。
【０００４】
合成紙タイプとしては、ユポコーポレーション社製、商品名「ユポ」、日清紡社製、商品名「ピーチ」等がある。
また、含浸紙タイプとしては、特許文献１に、原紙の表面に合成樹脂を含浸させてなり、該原紙が特定の塩素イオン濃度及び特定の硫酸イオン濃度を有する無塵紙が提案されており、特許文献２に、特定の樹脂エマルジョンを用いてなる無塵紙が提案されており、特許文献３に、古紙パルプを配合してなり、特定の物性を有する原紙に、樹脂エマルジョンを塗工・含浸させてなる含浸紙が提案されている。
【０００５】
【特許文献１】
特開２０００―３０３３８３号公報（請求項１、明細書段落００１２〜００１５）
【特許文献２】
特開２００１−２０７３９７号公報（請求項１、明細書段落００１８〜００２２）
【特許文献３】
特開２００２−２４２０９９号公報（請求項１、明細書段落００１４〜００２２）
【０００６】
【発明が解決しようとする課題】
しかしながら、上述の従来の無塵紙では未だ十分に要求を満たしていないのが現状である。
すなわち、合成紙タイプでは、発塵量は極めて少量となるものの原料の性質上熱に弱く、通常のオフセット印刷やプリンターを用いた印刷が困難となったり、印字性能が低下したりする。また、高価であるという問題もある。
また、含浸紙タイプは、合成紙タイプよりも安価にできるものの、発塵抑制効果と、製品のブロッキング、ベタツキ、裁断した際の刃の汚れ、印刷適性、筆記性等の種々の作業性とのバランスが悪いという問題がある。すなわち、発塵量抑制効果を向上させるべく、含浸薬剤の種類や含浸量を決定すると、作業性が低下し、逆に作業性を重視すると十分な発塵性抑制効果が得られないという問題がある。
【０００７】
従って、本発明の目的は、発塵性が低減され、且つ製造時の作業性にも優れた無塵紙を提供することにある。
【０００８】
【課題を解決するための手段】
本発明者らは、上記課題を解消すべく鋭意検討した結果、無塵紙を表面層、裏面層及び両層間に位置する中間層の３層の構造とし、中間層にのみ特定の熱溶融性繊維を配合し、表面層と裏面層とに水溶性高分子の水溶液を塗工することにより上記目的を達成しうることを知見し、本発明を完成するに至った。
【０００９】
すなわち、請求項１記載の発明は、少なくとも表面層、裏面層及び両層間に位置する中間層の３層以上の層を具備し、前記表面層、前記裏面層及び前記中間層を抄き合わせた後、ドライヤー表面に接触させて乾燥させた無塵紙であって、前記中間層のみに融点１４０℃以下の熱溶融性繊維を５〜５０重量％の範囲で配合し、前記表面層及び前記裏面層のそれぞれに水溶性高分子を主成分とする水溶液を０．１〜１．０ｇ／ｍ2塗工してなり、前記表面層及び前記裏面層の厚さは、３０〜１２０μｍであり、坪量は、２５〜１００ｇ／ｍ2で、前記中間層の厚さは、５０〜９００μｍであり、坪量は、４０〜７００ｇ／ｍ 2 で、前記無塵紙の全体の厚さは、１００〜１１００μｍであり、坪量は、９０〜９００ｇ／ｍ 2 である、ことを特徴とする無塵紙である。
【００１０】
また、請求項２記載の発明は、前記熱溶融性繊維の融点は、９０〜１４０℃である前記無塵紙である。
【００１１】
また、請求項３記載の発明は、ベック平滑度（ＪＩＳ Ｐ８１１９）は、１０〜４０秒である前記無塵紙である。
【００１２】
また、請求項４記載の発明は、前記水溶液における前記水溶性高分子の濃度は、０．５〜５．０重量％である前記無塵紙である。
【００１３】
【発明の実施の形態】
以下、本発明の無塵紙について更に詳細に説明する。
本発明の無塵紙は、少なくとも表面層、裏面層及び両層間に位置する中間層の３層以上の層を具備し、前記中間層のみに特定の融点を有する熱溶融性繊維を特定の配合量で配合し、前記表面層及び前記裏面層のそれぞれに水溶性高分子を主成分とする水溶液を特定の塗工量で塗工してなり、前記表面層及び前記裏面層並びに前記中間層が特定の厚さ及び坪量を有する。
【００１４】
以下、更に詳細に説明する。
本発明において前記表面層及び前記裏面層はパルプ繊維を主成分として構成されている。該パルプ繊維としては、下記するもの等を１種又は２種以上組み合わせて用いることができる。
ダグラスファー、ラジアータパイン、杉、松等の針葉樹、ユーカリ、オークなどの広葉樹を主原料としたクラフトパルプ（ＫＰ）；セミケミカルパルプ（ＳＣＰ）、砕木パルプ（ＧＰ）、ケミグランドパルプ（ＣＧＰ）、リファイナーフランドパルプ（ＲＧＰ）、ディンキングパルプ（ＤＩＰ）、ウエストパルプ（ＷＰ）。
【００１５】
また、前記の水溶性高分子を主成分とする水溶液に用いられる前記水溶性高分子としては、下記するもの等を１種又は２種以上組み合わせて用いることができる。
ポリビニルアルコール（ＰＶＡ、重合度は１０００〜２０００が好ましい。また、鹸化度は、９８％以上の完全鹸化タイプが好ましい、商品名「ＰＶＡ１１７」クラレ（株）製等の市販品を用いることもできる）、澱粉、ヒドロキシエチルセルロース（ＨＥＣ）。
【００１６】
また、前記水溶液における前記水溶性高分子の濃度は、０．５〜５．０重量％とするのが好ましく、１．５〜３．０重量％とするのが更に好ましい。
前記水溶性高分子の濃度が０．５重量％以上とすることにより、水溶性高分子による紙表面の被覆が不十分となることがなく、発塵抑制効果が十分に得られ、５．０重量％以下とすることにより、紙表面の水溶性高分子の膜に厚薄が発生することがなく、また印刷やプリンターでの印字の際にムラが発生することがなく、良好な印刷特性が得られる。
【００１７】
前記水溶液を表面層及び裏面層に塗工する際に採用される前記の特定の塗工量は、０．１〜１．０ｇ／ｍ2であり、好ましくは０．３〜０．８ｇ／ｍ2である。
前記塗工量が０．１ｇ／ｍ2未満であると、無塵紙表面からの紙粉の飛散を防止することが困難となり、１．０ｇ／ｍ2を超えると、無塵紙表面への印刷適性及び筆記性が低下する。
そして、前記水溶液を塗工することにより、表面層及び裏面層には、それぞれ、０．１〜１．０ｇ／ｍ2の水溶性高分子が塗工されることになる。また、有効成分は、いかなる水溶性高分子をいかなる濃度で用いるかにより異なるが、各層の表面側に極在する。
【００１８】
また、前記表面層と前記裏面層とは、それぞれ構成が同一でも異なっていても良い。
また、前記表面層及び前記裏面層には、消泡剤、着色剤、防錆剤、ワックス類等の他の成分を、本発明の所望の効果を阻害しない範囲で配合することもできる。
【００１９】
本発明において前記中間層は、パルプ繊維と前記熱溶融性繊維とを主成分として構成される。該パルプ繊維としては、下記するもの等を１種又は２種以上組み合わせて用いることができる。
ダグラスファー、ラジアータパイン、杉、松等の針葉樹、ユーカリ、オークなどの広葉樹を主原料としたクラフトパルプ（ＫＰ）；セミケミカルパルプ（ＳＣＰ）、砕木パルプ（ＧＰ）、ケミグランドパルプ（ＣＧＰ）、リファイナーフランドパルプ（ＲＧＰ）、ディンキングパルプ（ＤＩＰ）、ウエストパルプ（ＷＰ）。
【００２０】
前記熱溶融性繊維は、パルプ繊維の接着剤として機能するものであり、該熱溶融性繊維を中間層にのみ配合することにより乾燥時に抄紙機に紙が融着するようなことがなく、作業性を向上させることができる。
また、前記中間層に配合される前記熱溶融性繊維の有する特定の融点は、１４０℃以下であり、好ましくは９０〜１４０℃、更に好ましくは９０〜１３０℃である。一般に熱溶融繊維とは、ポリオレフィン合成パルプ、芯鞘タイプのポリエステル繊維、芯鞘タイプのポリプロピレン繊維、ポリアミド繊維などを指すが、これらの融点は概ね９０℃以上である。融点が低いほど乾燥時の熱エネルギーで溶融しやすくなるため、パルプ繊維の接着剤としての効果が高くなる。
前記融点が１４０℃を超えると、乾燥時の熱エネルギーで十分に溶融しなくなるのでパルプ繊維の接着剤として十分に機能しなくなり、紙断面からの紙粉の飛散を十分に防止できなくなる。
【００２１】
前記熱溶融性繊維の前記の特定の配合量は、５〜５０重量％（中間層全体の重量を１００重量部とした際に５〜５０重量部）であり、好ましくは１０〜４０重量％である。
前記配合量が、５重量％未満であると、パルプ繊維の接着剤としての機能が十分でなくなり紙断面からの紙粉の飛散を十分に防止できなくなり、５０重量％を超えると、紙粉飛散防止効果の向上は望めないばかりか、抄紙ワイヤー上にて紙層が形成される際、フロックと称される不均一な地合となりやすい。
【００２２】
前記熱溶融性繊維としては、下記するもの等を１種又は２種以上混合して用いることができる。
ポリオレフィン合成パルプ、芯鞘タイプのポリエステル系バインダー、芯鞘タイプのポリプロピレン系バインダー、ポリアミド系のバインダー。
上述の熱溶融繊維の中で特に効果が高いのがポリオレフィン合成パルプ（商品名「ＳＷＰ」、「Ｍ７００７」、「ＵＬ４１０」いずれも三井化学株式会社製等）である。これは該ポリオレフィン合成パルプが、木材パルプ繊維に非常に近い形状を有していることにより、抄紙工程にてワイヤー上で木材パルプ繊維と好適に絡み合い、均一なシートを形成し、ドライヤーの熱で溶融する際もシート上で均一に広がりやすく、好適な発塵抑制作用が得られるためである。
【００２３】
前記熱溶融性繊維は、中間層全体にほぼ均一に分散されて存在するのが好ましい。また、前記熱溶融性繊維は、無塵紙中において一旦溶融された後再度固化されて、各パルプ繊維を連結するように各パルプ繊維及び熱溶融性繊維同士で融着された状態で存在する。
また、前記中間層には、本発明の所望の効果を阻害しない範囲内で、消泡剤、着色剤、防錆剤、ワックス類等の他の成分を配合することもできる。
【００２４】
前記表面層及び前記裏面層の前記の特定の厚さは、３０〜１２０μｍであり、４０〜８０μｍとするのが更に好ましい。また、表面層及び裏面層の前記の特定の坪量は、２５〜１００ｇ／ｍ2であり、３０〜７０ｇ／ｍ2とするのが更に好ましい。
厚さが３０μｍ未満及び坪量が２５ｇ／ｍ2未満であると、製造時の抄紙乾燥工程でドライヤー処理を行うなど加熱処理を行った場合などにおいて、前記表面層及び前記裏面層側に熱溶融性繊維が滲出し、作業性が低下し、厚さが１２０μｍを超える場合及び坪量が１００ｇ／ｍ2を超えると、紙粉の飛散防止効果が不十分なものとなる。
【００２５】
中間層の厚さは、５０〜９００μｍとするのが好ましく、１００〜５００μｍとするのが更に好ましい。また、中間層の坪量は、４０〜７００ｇ／ｍ2とするのが好ましく、８０〜４００ｇ／ｍ2とするのが更に好ましい。
厚さを５０μｍ以上とすること、及び坪量を４０ｇ／ｍ2以上とすることにより、熱溶融繊維が配合されない表面層及び裏面層の割合が相対的に多くなり発塵性を低下させることがなく、９００μｍ以下とすること、及び７００ｇ／ｍ2以下とすることにより、紙厚のばらつきが大きくなったり、紙の地合調整が困難になる等操業性の面で不都合が発生することがなく、好ましい。
【００２６】
以上のことより、本発明の無塵紙の全体の厚さは、１００〜１１００μｍとするのが好ましく、２００〜７００μｍとするのが更に好ましい。また、全体の坪量は、９０〜９００ｇ／ｍ2とするのが好ましく、１５０〜６００ｇ／ｍ2とするのが更に好ましい。
【００２７】
また、本発明においては、表面層、裏面層及び中間層以外の層、例えば、表面層と中間層との間に単なるパルプ繊維のみからなる他の層を介在させることができる。
また、本発明の無塵紙のベック平滑度（ＪＩＳ Ｐ８１１９）は、１０〜４０秒であるのが、オフセット印刷やプリンターでの印刷、種々の作業性の点から好ましい。
【００２８】
次に、本発明の無塵紙の製造方法について説明する。
本発明の無塵紙は、下記の（１）〜（４）の各工程を行うことにより製造できる。
（１） 抄紙工程
（２） 抄き合わせ工程
（３） 乾燥工程
（４） 塗工工程
【００２９】
更に詳述すると、（１）抄紙工程は、表面層、裏面層及び中間層をそれぞれ抄紙する工程である。表面層及び裏面層については、パルプ繊維と必要により他の成分とを用いて、中間層については、パルプ繊維と熱溶融性繊維と必要により他の成分とを用いて、通常公知の手法により抄紙することにより行われる。
（２）抄き合わせ工程は、各層を湿紙の状態で重ね合わせて圧力をかけて脱水することにより各層を接着する工程であり、公知の抄き合わせ手法を特に制限なく用いて行うことができる。
ここで、上記抄紙工程と上記抄き合わせ工程とは、同時に行ってもよい。
【００３０】
（３）乾燥工程は、通常の湿式抄紙により作成した湿紙の公知の乾燥方法を特に制限なく用いて行うことができ、温度や時間の条件も任意である。
（４）塗工工程は、乾燥後の紙の表面、すなわち表面層及び裏面層に水溶性高分子の水溶液を塗工する工程である。塗工は、カレンダー処理と同時に行う。すなわち、カレンダーロールに水溶性高分子の水溶液を付着させ、該カレンダーロールの水溶液が所定量紙に転写されるように、カレンダー処理を行うことにより塗工することができる。このカレンダー処理における温度条件や圧力条件は、無塵紙の厚さ、坪量、カレンダー処理の設備により、本発明の所望の効果が得られるように適宜調節されるが、好ましくは上述の範囲のベック平滑度が得られる条件を選択して行うのが好ましい。
【００３１】
本発明の無塵紙は、エレクトロニクス産業、医薬品や食品の製造業、精密機械工業等の各種産業分野でのクリーンルーム内で用いられる紙の用途に好適である。具体的には、例えば、エレクトロニクス産業において、クリーンルーム内で、超ＬＳＩ等の半導体素子を装着して配線加工作業等を行うのに使用する電子部品実装用の機材の金蔵面又は金属メッキ面を保護したりするために用いる合紙などとして用いることができる。
【００３２】
そして、本発明の無塵紙は、上述のように構成されているので、裁断時の紙断面からの発塵を中間層で抑制すると共に表面からの発塵を表面層及び裏面層で抑制している。このため優れた防塵性を発揮する。また、熱溶融性繊維を中間層にのみ配合し、表面層及び裏面層には配合していないので抄紙乾燥工程でドライヤー処理などの加熱処理を行った際に抄紙設備に熱溶融繊維が融着する事がなく、作業に支障をきたすことがなく、製造時における作業性にも優れる。さらには、樹脂エマルジョンを使用していないので、製品のブロッキングやベタツキ、裁断時の刃の汚れ、印刷適性などの種々の作業性にも優れている。
【００３３】
【実施例】
以下、本発明を実施例及び比較例により更に具体的に説明するが、本発明は、これらに制限されるものではない。
なお、以下の文中「部」は重要部を示し、「％」は重量％を示す。
〔実施例１〕
以下の原料を用いて、下記の製造法に従い、表面層、裏面層及び両層間に位置する中間層からなる３層構造の無塵紙を得た。
【００３４】
＜原料＞
・表面層及び裏面層
パルプ繊維スラリー；針葉樹晒クラフトパルプ（ＮＢＫＰ）５０部、広葉樹晒クラフトパルプ（ＬＢＫＰ）５０部からなるパルプスラリーをカナディアンスタンダードフリーネス（ＣＳＦ）４５０ｃｃに調整したものに、紙力剤（商品名「ハーマイドＢ１５」ハリマ化成（株）製）３部を配合し、これらの原料に硫酸バンドを添加してｐＨを５．０に調整した。
水溶性高分子；完全鹸化タイプのポリビニルアルコール（商品名「ＰＶＡ１１７」クラレ（株）製）を使用した、鹸化度は９８．５％、重合度は１７００である。
水溶液濃度；上記ポリビニルアルコールを水に溶解し、ＰＶＡ濃度２．５％の水溶液とした。
水溶液塗工量；表面層及び裏面層それぞれに０．５ｇ／ｍ2塗布した。
・中間層
パルプ繊維スラリー；針葉樹晒クラフトパルプ（ＮＢＫＰ）２５部、広葉樹晒クラフトパルプ（ＬＢＫＰ）５０部及び 熱溶融性繊維〔商品名「Ｍ７００７」三井化学（株）製、融点約１２０℃〕２５部からなるパルプスラリーをカナディアンスタンダードフリーネス（ＣＳＦ）４００ｃｃに調整したものに紙力剤（商品名「ハーマイドＢ１５」ハリマ化成（株）製）３部を配合しこれらの原料に硫酸バンドを添加してｐＨを５．０に調整した。
【００３５】
＜製造法＞
抄紙工程及び抄き合わせ工程；円網多層抄紙機を使用し、表面層、中間層、裏面層の３層抄き合わせ構造の紙層を作製した。抄き合わせは湿潤状態のまま重ね合わせ、プレスロールを用いて線圧８ｋｇ／ｃｍで４回加圧し脱水を行い、各層を接着した。このときの表面層及び裏面層の厚みは各々７０μｍ、坪量は５０ｇ／ｍ2とした。また、全体の厚みは４００μｍ、坪量は３２０ｇ／ｍ2に調整した。
乾燥工程；表面温度を１４０℃に調節した金属ドライヤーの表面に５分間接触させ、熱溶融繊維を溶融させた。
塗工工程；ロール表面温度６０℃のスーパーカレンダーを使用し、線圧４０ｋｇ／ｃｍで２回カレンダー処理を行うと共に、該カレンダーロールに前記水溶性高分子の水溶液を含浸させておき、上述の塗工量で表面層及び裏面層に該水溶液が転写されるようにして行った。
【００３６】
得られた無塵紙について、坪量及び厚さを測定し、ベック平滑度及び発塵性、各種適性を評価した。それぞれの測定法及び評価法を以下に、結果を表１に示す。
・坪量；ＪＩＳ Ｐ ８１２４
・厚さ；ＪＩＳ Ｐ ８１１８
【００３７】
・発塵性
（１） 擦りによる発塵度
Ａ５サイズの試験片２枚をクリーン状態に調整した測定器（商品名「グローブボックス」日本エアーテック（株）製、清浄度：ＵＳ．Ｆｅｄ．Ｓｔｄ．２０９ＥクラスＭ２．５）内で、表裏重ね合わせ３回／１０秒の速度で３分２０秒間手で擦り合わせた。測定開始から終了までグローブボックス内の空気を吸引し、発生した０．１μｍ以上の塵の個数をパーティクルカウンター（型式「ＫＣ−２２Ａ」リオン（株）製）にて測定した。捕集した０．１μｍ以上の塵の個数を空気１リットルあたりに含まれる個数に換算し、これを発塵度とした。
【００３８】
（２）揉みによる発塵度
Ａ５サイズの試験片１枚を、クリーン状態に調整した測定器（商品名「グローブボックス」日本エアーテック（株）製、清浄度：ＵＳ．Ｆｅｄ．Ｓｔｄ．２０９ＥクラスＭ２．５）内で、１回／１５秒の割合で３分２０秒間手で揉んだ。次いで、上記の（１）擦りによる発塵度と同様にして０．１μｍ以上の塵の個数を測定し、空気１リットルあたりの個数に換算し、これを発塵度とした。
【００３９】
（３）引き裂き揉み発塵度
Ａ５サイズの試験片１枚を、クリーン状態に調整した測定器（商品名「グローブボックス」日本エアーテック（株）製、清浄度：ＵＳ．Ｆｅｄ．Ｓｔｄ．２０９ＥクラスＭ２．５）内で、５秒ごとに４カ所（４ｃｍ間隔）を引き裂いて５枚とし、これらを重ね合わせ、その後揉み試験と度紆余運して１回／１５秒の割合で３分間手で揉んだ。次いで、上記の（１）擦りによる発塵度と同様にして０．１μｍ以上の塵の個数を測定し、空気１リットルあたりの個数に換算し、これを発塵度とした。
【００４０】
・印刷適性
作製した無塵紙について平判用オフセット印刷機を使用して、マゼンタ、シアン、イエロー、ブラックの４色印刷を２０００枚連続で行った。２０００枚印刷後のブランケットや走行経路に付着した紙粉及び印刷品質（鮮明さ、印刷ムラ、白ぬけの有無）を目視で確認した。
○：紙粉発生がほとんどなく、印刷品質も良好なもの
△：紙粉が少量発生する、もしくは印刷品質が若干低下するものの、商品価値を有しているもの
×：紙粉が大量に発生して印刷継続が不可能になる、もしくは印刷品質が劣り、商品価値がないもの
【００４１】
・加工適性
作製した無塵紙をギロチンカッターを使用して断裁作業を行い、カッター刃先への紙粉や粘着物付着量、紙捌きのし易さを判定した。
○：紙粉や粘着物付着がほとんどなく、紙捌き作業性も良好なもの
△：紙粉や粘着物が少量付着する、もしくは紙がやや滑りにくく、紙捌きに若干時間を要するもの
×：紙粉や粘着物が付着し頻繁に掃除が必要となる、もしくは紙捌きに多大な時間を要するもの
【００４２】
・抄紙適性
無塵紙抄造時、操業トラブルが発生しなかったものは○とし、何らかのトラブルが生じたものを×とした。
×（１）：抄紙ワイヤー上でパルプ原料がフロックと称される不均一な状態となり、地合が悪化した。
×（２）：乾燥工程において、ドライヤー表面に熱溶融繊維が融着し、連続操業が困難になった。
×（３）：表面層の地合が悪く、坪量や紙厚のプロファイルが悪化した。
△（４）：表面への水溶性高分子を塗布するカレンダー設備に水溶性高分子の粕が付着し、紙表面に欠陥が発生した。
【００４３】
〔実施例２〕
中間層のパルプ繊維及び熱溶融繊維の配合割合を、ＮＢＫＰ３０部、ＬＢＫＰ６０部、熱溶融繊維「Ｍ７００７」１０部とした以外は、実施例１と同様にして、無塵紙を得た。得られた無塵紙について実施例１と同様にして測定及び評価を行った。その結果を表１に示す。
【００４４】
〔実施例３〕
中間層のパルプ繊維及び熱溶融繊維の配合割合を、ＮＢＫＰ２０部、ＬＢＫＰ３５部、熱溶融繊維「Ｍ７００７」４５部とした以外は、実施例１と同様にして、無塵紙を得た。得られた無塵紙について実施例１と同様にして測定及び評価を行った。その結果を表１に示す。
【００４５】
〔実施例４〕
表面層及び裏面層の厚みを各々４０μｍ、坪量を３０ｇ／ｍ2とした以外は、実施例１と同様にして、無塵紙を得た。得られた無塵紙について実施例１と同様にして測定及び評価を行った。その結果を表１に示す。
【００４６】
〔実施例５〕
表面層及び裏面層の厚みを各々１２０μｍ、坪量を９０ｇ／ｍ2とした以外は、実施例１と同様にして、無塵紙を得た。得られた無塵紙について実施例１と同様にして測定及び評価を行った。その結果を表１に示す。
【００４７】
〔実施例６〕
表面層及び裏面層へのポリビニルアルコール塗布量をそれぞれ０．２ｇ／ｍ2（水溶液濃度０．５％）とした以外は、実施例１と同様にして、無塵紙を得た。得られた無塵紙について実施例１と同様にして測定及び評価を行った。その結果を表１に示す。
【００４８】
〔実施例７〕
表面層及び裏面層へのポリビニルアルコール塗布量をそれぞれ１．０ｇ／ｍ2（水溶液濃度５．０％）とした以外は、実施例１と同様にして、無塵紙を得た。得られた無塵紙について実施例１と同様にして測定及び評価を行った。その結果を表１に示す。
【００４９】
〔実施例８〕
熱溶融繊維を商品名「ＵＬ４１０」（三井化学（株）製、融点１３５℃）とした以外は、実施例１と同様にして、無塵紙を得た。得られた無塵紙について実施例１と同様にして測定及び評価を行った。その結果を表１に示す。
実施例１〜８の無塵紙は、擦り、揉み、引き裂き揉み方のいずれの発塵性試験においても発塵量は少なく、無塵紙としての品質を満たすものであった。さらに印刷適性、裁断時の刃汚れ、表面のベタツキなどの作業性に関する品質も優れており、従来の無塵紙の問題点を解消したものであった。
【００５０】
〔比較例１〕
中間層のパルプ繊維及び熱溶融繊維の配合割合を、ＮＢＫＰ３５部、ＬＢＫＰ６２部、熱溶融繊維「Ｍ７００７」３部とした以外は、実施例１と同様にして、紙を得た。得られた紙について実施例１と同様にして測定及び評価を行った。その結果を表１に示す。
得られた紙は、引き裂き揉み試験において紙断面からの紙粉発生量が多く、無塵紙としては不適であった。
【００５１】
〔比較例２〕
中間層のパルプ繊維及び熱溶融繊維の配合割合を、ＮＢＫＰ１５部、ＬＢＫＰ２５部、熱溶融繊維「Ｍ７００７」６０部とした以外は、実施例１と同様にして、紙を得た。得られた紙について実施例１と同様にして測定及び評価を行った。その結果を表１に示す。
得られた紙は、抄紙時にフロックと称される不均一な地合の紙となり、坪量や紙厚の調整が困難で、安定操業することが不可能であった。
【００５２】
〔比較例３〕
熱溶融繊維を商品名「Ｅ７９０」三井化学（株）製、融点１５０℃とした以外は、実施例１と同様にして、紙を得た。得られた紙について実施例１と同様にして測定及び評価を行った。その結果を表１に示す。
得られた紙は、引き裂き揉み試験において紙断面からの紙粉発生量が多く、無塵紙としては不適であった。
【００５３】
〔比較例４〕
表面層及び裏面層の厚みを各々２０μｍ、坪量を１５ｇ／ｍ2とし、中間層の厚みを３６０μｍ、坪量を２９０ｇ／ｍ2として全体の厚みを４００μｍ、坪量を３２０ｇ／ｍ2とした以外は、実施例１と同様にして、紙を得た。得られた紙について実施例１と同様にして測定及び評価を行った。その結果を表１に示す。
得られた紙は、抄造中ドライヤー表面に中間層に配合した熱溶融繊維が溶融して付着し著しい汚れとなり、操業が困難になった。
【００５４】
〔比較例５〕
表面層及び裏面層の厚みを各々１６０μｍ、坪量を１２５ｇ／ｍ2とし、中間層の厚みを８０μｍ、坪量を５０ｇ／ｍ2として全体の厚みを４００μｍ、坪量を３２０ｇ／ｍ2とした以外は、実施例１と同様にして、紙を得た。得られた紙について実施例１と同様にして測定及び評価を行った。その結果を表１に示す。
得られた紙は、中間層が薄いため、熱溶融繊維の含有量が少なく、揉み及び引き裂き揉み試験において紙断面からの紙粉発生量が多く、無塵紙としては不適であった。
【００５５】
〔比較例６〕
表面層及び裏面層へのポリビニルアルコール塗布量をそれぞれ０．０５ｇ／ｍ2（水溶液濃度０．２５％）とした以外は、実施例１と同様にして、紙を得た。得られた紙について実施例１と同様にして測定及び評価を行った。その結果を表１に示す。
得られた紙は、擦り及び揉み試験において紙表面からの紙粉発生量が多く、無塵紙としては不適であった。
【００５６】
〔比較例７〕
表面層及び裏面層へのポリビニルアルコール塗布量をそれぞれ１．３ｇ／ｍ2（水溶液濃度６．０％）とした以外は、実施例１と同様にして、紙を得た。得られた紙について実施例１と同様にして測定及び評価を行った。その結果を表１に示す。
得られた紙は、オフセット印刷時にインキの定着性が悪く印刷品質が劣っており、従来の無塵紙の問題点を解消することはできなかった。
【００５７】
〔比較例８〕
市販の無塵紙（リンテック（株）製、商品名「スタクリン」）を使用し、実施例１と同様にして測定及び評価を行った。その結果を表１に示す。
この無塵紙は、紙表面や断面からの紙粉発生量は良好なものの、オフセット印刷時にインキの定着性が悪く印刷品質が劣っているほか、裁断処理時に紙表面のベタツキがあり、作業性に問題があった。
【００５８】
〔比較例９〕
市販の無塵紙（王子製紙（株）製、商品名「ＯＫクリン」）を使用し、実施例１と同様にして測定及び評価を行った。その結果を表１に示す。
この無塵紙は、紙表面や断面からの紙粉発生量は良好なものの、オフセット印刷時にインキの定着性が悪く印刷品質が劣っているほか、裁断処理時に紙表面のベタツキがあり、作業性に問題があった。
【００５９】
【表１】
【発明の効果】
以上詳述したように、本発明の無塵紙は、発塵性が低減され、且つ製造時の作業性にも優れたものである。[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a dust-free paper suitably used in a clean room or the like, and more particularly to a dust-free paper having a low dust generation property and excellent workability during production.
[0002]
[Prior art]
In electronics industries such as semiconductors including VLSI, pharmaceutical and product manufacturing industries, and advanced industries such as precision machinery industries, dust and the like cause serious adverse effects on product defects, quality, and yield. Therefore, the production lines in these industries are placed in a clean room free from dust, and various operations are performed in an environment free of dust in the clean room.
In a clean room, it is natural to prevent the dust from being brought into the interior as much as possible, but at the same time, it is necessary to suppress the generation of the dust accompanying the work inside as much as possible.
[0003]
As one of the various operations performed in the clean room, dustless paper is used to suppress the generation of dust in recording, copying, creating slips, and the like associated with various operations in the clean room.
As such dust-free paper, there are a synthetic paper type prepared based on polypropylene resin or nonwoven fabric, and an impregnated paper type in which a base paper mainly composed of natural pulp is impregnated with a binder resin.
[0004]
Synthetic paper types include those manufactured by Yupo Corporation, trade name “Yupo”, manufactured by Nisshinbo Co., Ltd., and trade name “Peach”.
In addition, as an impregnated paper type, Patent Document 1 proposes a dust-free paper in which a surface of a base paper is impregnated with a synthetic resin, and the base paper has a specific chlorine ion concentration and a specific sulfate ion concentration. Document 2 proposes a dust-free paper using a specific resin emulsion. Patent Document 3 is a mixture of waste paper pulp, and a base paper having specific physical properties is coated and impregnated with the resin emulsion. An impregnated paper has been proposed.
[0005]
[Patent Document 1]
Japanese Patent Laid-Open No. 2000-303383 (Claim 1, Description Paragraphs 0012 to 0015)
[Patent Document 2]
Japanese Unexamined Patent Publication No. 2001-207397 (Claim 1, Description Paragraphs 0018 to 0022)
[Patent Document 3]
Japanese Patent Laid-Open No. 2002-242099 (Claim 1, Description Paragraphs 0014 to 0022)
[0006]
[Problems to be solved by the invention]
However, the above-described conventional dust-free paper still does not sufficiently meet the requirements.
That is, in the synthetic paper type, although the amount of dust generation is extremely small, it is weak against heat due to the nature of the raw material, and it becomes difficult to perform normal offset printing or printing using a printer, or the printing performance is lowered. There is also a problem that it is expensive.
In addition, the impregnated paper type can be made cheaper than the synthetic paper type, but it has the effect of suppressing dust generation and various workability such as blocking, stickiness of the product, dirt on the blade when cutting, printability, writing property, etc. There is a problem of poor balance. That is, if the type and amount of impregnation agent are determined in order to improve the dust generation suppression effect, the workability is lowered, and conversely, if the workability is emphasized, a sufficient dust generation suppression effect cannot be obtained. is there.
[0007]
Accordingly, an object of the present invention is to provide a dust-free paper having reduced dust generation and excellent workability during production.
[0008]
[Means for Solving the Problems]
As a result of intensive studies to solve the above-mentioned problems, the present inventors have made the dust-free paper into a three-layer structure of a front surface layer, a back surface layer, and an intermediate layer located between both layers, and a specific hot-melt fiber only in the intermediate layer It was discovered that the above-mentioned object can be achieved by coating the surface layer and the back layer with an aqueous solution of a water-soluble polymer, and the present invention has been completed.
[0009]
That is, the invention of claim 1 comprises at least three layers of a surface layer, a back surface layer, and an intermediate layer located between both layers,After making the surface layer, the back layer and the intermediate layer together, it is a dust-free paper dried by contacting the dryer surface,A hot-melt fiber having a melting point of 140 ° C. or lower is blended in an amount of 5 to 50% by weight only in the intermediate layer, and an aqueous solution containing a water-soluble polymer as a main component is added to each of the surface layer and the back layer. ~ 1.0 g / m2The thickness of the surface layer and the back layer is 30 to 120 μm, and the basis weight is 25 to 100 g / m.2soThe intermediate layer has a thickness of 50 to 900 μm and a basis weight of 40 to 700 g / m. 2 The total thickness of the dust-free paper is 100 to 1100 μm, and the basis weight is 90 to 900 g / m. 2 It is characterized byIt is dust-free paper.
[0010]
Moreover, invention of Claim 2 is the said dust-free paper whose melting | fusing point of the said heat-meltable fiber is 90-140 degreeC.
[0011]
The invention according to claim 3 is the dust-free paper having a Beck smoothness (JIS P8119) of 10 to 40 seconds.
[0012]
The invention according to claim 4 is the dust-free paper, wherein the concentration of the water-soluble polymer in the aqueous solution is 0.5 to 5.0% by weight.
[0013]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, the dust-free paper of the present invention will be described in more detail.
The dust-free paper of the present invention comprises at least three layers of a surface layer, a back surface layer, and an intermediate layer located between both layers, and a specific blending amount of a heat-meltable fiber having a specific melting point only in the intermediate layer. And the surface layer and the back layer are coated with a specific coating amount of an aqueous solution mainly composed of a water-soluble polymer on each of the surface layer and the back layer.And the intermediate layerHave a specific thickness and basis weight.
[0014]
This will be described in more detail below.
In the present invention, the front surface layer and the back surface layer are composed mainly of pulp fibers. As this pulp fiber, the following can be used alone or in combination of two or more.
Kraft pulp (KP) made mainly of broad-leaved trees such as Douglas fir, Radiata pine, cedar and pine, eucalyptus and oak; semi-chemical pulp (SCP), groundwood pulp (GP), chemi-ground pulp (CGP), Refiner Fland pulp (RGP), Dinking pulp (DIP), Waist pulp (WP).
[0015]
Moreover, as the water-soluble polymer used in the aqueous solution containing the water-soluble polymer as a main component, the following may be used alone or in combination of two or more.
Polyvinyl alcohol (PVA, the degree of polymerization is preferably 1000 to 2000. The saponification degree is preferably a complete saponification type of 98% or more, and a commercial product such as “PVA117” manufactured by Kuraray Co., Ltd. may be used) , Starch, hydroxyethyl cellulose (HEC).
[0016]
The concentration of the water-soluble polymer in the aqueous solution is preferably 0.5 to 5.0% by weight, more preferably 1.5 to 3.0% by weight.
When the concentration of the water-soluble polymer is 0.5% by weight or more, the paper surface is not sufficiently covered with the water-soluble polymer, and a dust generation suppressing effect is sufficiently obtained. By setting the weight percent or less, the water-soluble polymer film on the paper surface does not become thick or thin, and there is no unevenness when printing or printing with a printer. It is done.
[0017]
The specific coating amount employed when the aqueous solution is applied to the front surface layer and the back surface layer is 0.1 to 1.0 g / m.2Preferably 0.3 to 0.8 g / m2It is.
The coating amount is 0.1 g / m2If it is less than 1.0 g / m, it becomes difficult to prevent the scattering of paper dust from the dust-free paper surface.2If it exceeds, the printability and writing property on the surface of dust-free paper will be deteriorated.
Then, by applying the aqueous solution, 0.1 to 1.0 g / m for each of the front surface layer and the back surface layer.2The water-soluble polymer is applied. Further, the active ingredient is extremely present on the surface side of each layer, although it varies depending on what concentration of water-soluble polymer is used.
[0018]
Moreover, the said surface layer and the said back surface layer may respectively be the same, or may differ.
Moreover, other components, such as an antifoamer, a coloring agent, a rust preventive agent, and waxes, can also be mix | blended with the said surface layer and the said back surface layer in the range which does not inhibit the desired effect of this invention.
[0019]
In the present invention, the intermediate layer is composed mainly of pulp fibers and the heat-meltable fibers. As this pulp fiber, the following can be used alone or in combination of two or more.
Kraft pulp (KP) made mainly of broad-leaved trees such as Douglas fir, Radiata pine, cedar and pine, eucalyptus and oak; semi-chemical pulp (SCP), groundwood pulp (GP), chemi-ground pulp (CGP), Refiner Fland pulp (RGP), Dinking pulp (DIP), Waist pulp (WP).
[0020]
The heat-meltable fiber functions as an adhesive for pulp fibers, and by blending the heat-meltable fiber only in the intermediate layer, the paper is not fused to the paper machine during drying. Can be improved.
Moreover, the specific melting point which the said hot-melt fiber mix | blended with the said intermediate | middle layer has is 140 degrees C or less, Preferably it is 90-140 degreeC, More preferably, it is 90-130 degreeC. In general, the hot-melt fiber refers to a polyolefin synthetic pulp, a core-sheath type polyester fiber, a core-sheath type polypropylene fiber, a polyamide fiber, and the like, and the melting point thereof is approximately 90 ° C. or higher. The lower the melting point, the easier it is to melt with the thermal energy at the time of drying, so the effect of the pulp fiber as an adhesive increases.
If the melting point exceeds 140 ° C., it will not be sufficiently melted by the thermal energy during drying, so that it will not function sufficiently as an adhesive for pulp fibers, and scattering of paper dust from the paper cross section cannot be prevented sufficiently.
[0021]
The specific blending amount of the heat-meltable fiber is 5 to 50% by weight (5 to 50 parts by weight when the total weight of the intermediate layer is 100 parts by weight), preferably 10 to 40% by weight. is there.
When the blending amount is less than 5% by weight, the function of the pulp fiber as an adhesive is not sufficient, and the scattering of the paper powder from the paper cross section cannot be sufficiently prevented. When the blending amount exceeds 50% by weight, the paper powder is scattered. Not only can the prevention effect be improved, but also when a paper layer is formed on the papermaking wire, it tends to be a non-uniform texture called floc.
[0022]
As said heat-meltable fiber, the following etc. can be used 1 type or in mixture of 2 or more types.
Polyolefin synthetic pulp, core-sheath type polyester binder, core-sheath type polypropylene binder, polyamide binder.
Among the above-mentioned hot-melt fibers, polyolefin synthetic pulp (trade names “SWP”, “M7007”, “UL410” are all manufactured by Mitsui Chemicals, Inc.) is particularly effective. This is because the polyolefin synthetic pulp has a shape very close to that of wood pulp fibers, so that it is properly entangled with the wood pulp fibers on the wire in the paper making process, forming a uniform sheet, and the heat of the dryer. This is because even when melted, it is easy to spread evenly on the sheet, and a suitable dust suppression effect is obtained.
[0023]
It is preferable that the hot-melt fiber is present in a substantially uniformly dispersed state throughout the intermediate layer. The heat-meltable fibers are once melted in dust-free paper and then solidified again, and are present in a state where the pulp fibers and the heat-meltable fibers are fused together so as to connect the pulp fibers.
In addition, the intermediate layer may contain other components such as an antifoaming agent, a colorant, a rust inhibitor, and waxes within a range that does not impair the desired effect of the present invention.
[0024]
The specific thicknesses of the front surface layer and the back surface layer are 30 to 120 μm, and more preferably 40 to 80 μm. The specific basis weight of the front surface layer and the back surface layer is 25 to 100 g / m.230 to 70 g / m2Is more preferable.
The thickness is less than 30 μm and the basis weight is 25 g / m.2If it is less than, in the case of performing a heat treatment such as a dryer treatment in the paper-making drying process at the time of manufacture, the heat-melting fibers ooze out on the surface layer and the back surface layer side, workability is reduced, and the thickness When the weight exceeds 120 μm and the basis weight is 100 g / m2If it exceeds 1, the effect of preventing the scattering of paper dust will be insufficient.
[0025]
The thickness of the intermediate layer is preferably 50 to 900 μm, and more preferably 100 to 500 μm. The basis weight of the intermediate layer is 40 to 700 g / m.2It is preferably 80 to 400 g / m.2Is more preferable.
The thickness is 50 μm or more, and the basis weight is 40 g / m.2By setting it as the above, the ratio of the surface layer and back surface layer in which a hot melt fiber is not mix | blended is relatively increased, and it does not reduce dust generation property, it shall be 900 micrometers or less, and 700 g / m.2By making the following, it is preferable that there is no inconvenience in terms of operability, such as variation in paper thickness becoming large and adjustment of paper formation being difficult.
[0026]
From the above, the total thickness of the dust-free paper of the present invention is preferably 100 to 1100 μm, and more preferably 200 to 700 μm. The overall basis weight is 90 to 900 g / m.2It is preferably 150 to 600 g / m.2Is more preferable.
[0027]
In the present invention, a layer other than the front surface layer, the back surface layer, and the intermediate layer, for example, another layer composed of mere pulp fibers can be interposed between the front surface layer and the intermediate layer.
Further, the Beck smoothness (JIS P8119) of the dust-free paper of the present invention is preferably 10 to 40 seconds from the viewpoint of offset printing, printing with a printer, and various workability.
[0028]
Next, the method for producing dust-free paper of the present invention will be described.
The dust-free paper of the present invention can be produced by performing the following steps (1) to (4).
(1) Paper making process
(2) Making process
(3) Drying process
(4) Coating process
[0029]
More specifically, (1) the paper making step is a step of making a paper on the front layer, the back layer and the intermediate layer. For the surface layer and the back surface layer, pulp fibers and other components are used if necessary, and for the intermediate layer, pulp fibers, heat-meltable fibers and optionally other components are used, and papermaking is performed by a generally known method. Is done.
(2) The combining process is a process in which the layers are bonded together by overlaying each layer in a wet paper state and applying pressure to dehydrate, and can be performed using a known combining method without any particular limitation. it can.
Here, the paper making process and the paper making process may be performed simultaneously.
[0030]
(3) The drying step can be carried out without particular limitation using a known wet paper drying method prepared by ordinary wet papermaking, and the conditions of temperature and time are also arbitrary.
(4) The coating process is a process in which an aqueous solution of a water-soluble polymer is applied to the surface of the paper after drying, that is, the surface layer and the back layer. Coating is performed simultaneously with the calendar process. That is, the coating can be performed by attaching an aqueous solution of a water-soluble polymer to the calendar roll and performing a calendar process so that the aqueous solution of the calendar roll is transferred to a predetermined amount of paper. The temperature condition and pressure condition in the calendering process are appropriately adjusted depending on the thickness of the dust-free paper, the basis weight, and the calendering equipment so as to obtain the desired effect of the present invention. It is preferable to carry out by selecting a condition for obtaining smoothness.
[0031]
The dust-free paper of the present invention is suitable for paper used in clean rooms in various industrial fields such as the electronics industry, pharmaceutical and food manufacturing industries, and precision machinery industries. Specifically, for example, in the electronics industry, in a clean room, the metal or metal plating surface of equipment for mounting electronic components used to perform wiring processing work by mounting semiconductor elements such as VLSI is protected. It can be used as a slip sheet used for printing.
[0032]
Since the dust-free paper of the present invention is configured as described above, dust generation from the paper cross section during cutting is suppressed by the intermediate layer and dust generation from the front surface is suppressed by the front surface layer and the back surface layer. Yes. For this reason, it exhibits excellent dust resistance. In addition, hot melt fibers are blended only in the intermediate layer and not in the front and back layers, so when heat treatment such as dryer treatment is performed in the paper drying process, the hot melt fibers are fused to the paper making equipment. It does not interfere with the work, and is excellent in workability during manufacturing. Furthermore, since a resin emulsion is not used, it is excellent in various workability such as product blocking and stickiness, blade contamination during cutting, and printability.
[0033]
【Example】
EXAMPLES Hereinafter, although an Example and a comparative example demonstrate this invention further more concretely, this invention is not restrict | limited to these.
In the following text, “part” indicates an important part, and “%” indicates weight%.
[Example 1]
Using the following raw materials, a dust-free paper having a three-layer structure consisting of a front surface layer, a back surface layer and an intermediate layer located between both layers was obtained according to the following production method.
[0034]
<Raw material>
・ Front and back layers
Pulp fiber slurry; a pulp slurry comprising 50 parts of softwood bleached kraft pulp (NBKP) and 50 parts of hardwood bleached kraft pulp (LBKP) adjusted to 450 cc of Canadian Standard Freeness (CSF). 3 parts of “Harima Kasei Co., Ltd.” was blended, and a sulfuric acid band was added to these raw materials to adjust the pH to 5.0.
Water-soluble polymer: A completely saponified polyvinyl alcohol (trade name “PVA117” manufactured by Kuraray Co., Ltd.) was used. The degree of saponification was 98.5% and the degree of polymerization was 1700.
Aqueous solution concentration: The above polyvinyl alcohol was dissolved in water to obtain an aqueous solution having a PVA concentration of 2.5%.
Aqueous solution coating amount: 0.5 g / m for each of the front surface layer and the back surface layer2Applied.
・ Middle layer
Pulp fiber slurry: Containing 25 parts of softwood bleached kraft pulp (NBKP), 50 parts of hardwood bleached kraft pulp (LBKP) and 25 parts of heat-meltable fiber (trade name “M7007” manufactured by Mitsui Chemicals, Inc., melting point: about 120 ° C.) The pulp slurry was adjusted to Canadian Standard Freeness (CSF) 400 cc and 3 parts of a paper strength agent (trade name “Harmide B15” manufactured by Harima Kasei Co., Ltd.) was added. Adjusted to 0.0.
[0035]
<Production method>
Paper making process and making process: Using a circular multi-layer paper machine, a paper layer having a three-layer making structure of a surface layer, an intermediate layer, and a back layer was prepared. The sheets were laminated in a wet state, dehydrated by pressurization four times at a linear pressure of 8 kg / cm using a press roll, and the layers were bonded. At this time, the thickness of the front surface layer and the back surface layer is 70 μm, respectively, and the basis weight is 50 g / m.2It was. The overall thickness is 400 μm and the basis weight is 320 g / m.2Adjusted.
Drying step: The surface of the metal dryer whose surface temperature was adjusted to 140 ° C. was contacted for 5 minutes to melt the hot-melt fiber.
Coating process: Using a super calender with a roll surface temperature of 60 ° C., calendering is performed twice at a linear pressure of 40 kg / cm, and the calender roll is impregnated with the aqueous solution of the water-soluble polymer. The aqueous solution was transferred to the front surface layer and the back surface layer at a work amount.
[0036]
About the obtained dust-free paper, basic weight and thickness were measured and Beck smoothness, dust generation property, and various suitability were evaluated. Each measurement method and evaluation method are shown below, and the results are shown in Table 1.
・ Weight: JIS P 8124
・ Thickness: JIS P 8118
[0037]
・ Dust generation
(1) Degree of dust generation by rubbing
Front and back layers in a measuring instrument (trade name “Glove Box” manufactured by Nippon Airtech Co., Ltd., cleanliness: US.Fed.Std.209E class M2.5) with two A5 size test pieces adjusted to a clean state. A total of 3 times / 10 seconds was rubbed by hand for 3 minutes and 20 seconds. The air in the glove box was sucked from the start to the end of the measurement, and the number of generated dusts of 0.1 μm or more was measured with a particle counter (model “KC-22A” manufactured by Lion Co., Ltd.). The number of collected dust of 0.1 μm or more was converted to the number contained per liter of air, and this was used as the degree of dust generation.
[0038]
(2) Degree of dust generation due to stagnation
In a measuring instrument (trade name “Glove Box” manufactured by Nippon Airtech Co., Ltd., cleanliness: US.Fed.Std.209E class M2.5) adjusted to a clean state for one A5 size test piece It was massaged by hand for 3 minutes and 20 seconds at a rate of times / 15 seconds. Subsequently, the number of dusts of 0.1 μm or more was measured in the same manner as the above (1) degree of dusting by rubbing, converted to the number per 1 liter of air, and this was used as the degree of dusting.
[0039]
(3) Degree of dust generation
In a measuring instrument (trade name “Glove Box” manufactured by Nippon Airtech Co., Ltd., cleanliness: US.Fed.Std.209E class M2.5) in which one A5 size test piece was adjusted to a clean state, 5 Four places (4 cm intervals) were torn every second to make 5 sheets, and after that, they were overlapped and then squeezed by hand for 15 minutes at a rate of once / 15 seconds. Subsequently, the number of dusts of 0.1 μm or more was measured in the same manner as the above (1) degree of dusting by rubbing, converted to the number per 1 liter of air, and this was used as the degree of dusting.
[0040]
・ Printability
The produced dust-free paper was subjected to continuous printing of 2000 sheets of four colors of magenta, cyan, yellow, and black using a flat offset printer. The blanket after printing 2,000 sheets, paper dust adhering to the traveling route, and print quality (clearness, printing unevenness, presence of whitening) were visually confirmed.
○: Paper dust is hardly generated and print quality is good
Δ: A small amount of paper dust is generated or the print quality is slightly reduced, but it has commercial value
×: A large amount of paper dust is generated and printing cannot be continued, or the printing quality is inferior and there is no commercial value
[0041]
・ Processability
The produced dust-free paper was cut using a guillotine cutter, and the amount of paper dust and sticky material adhering to the cutter blade edge and the ease of papermaking were determined.
○: Paper dust and adhesives are hardly adhered, and paper-making workability is good.
Δ: A small amount of paper dust or adhesive adheres to the paper, or the paper is slightly slippery and requires some time for papermaking.
X: Paper dust or adhesive adheres and frequently needs cleaning, or requires a long time for papermaking
[0042]
・ Paper suitability
When dust-free paper was made, “O” indicates that no operation trouble occurred, and “X” indicates that some trouble occurred.
X (1): The pulp raw material became a non-uniform state called floc on the papermaking wire, and the formation deteriorated.
X (2): In the drying process, the hot-melt fiber was fused to the dryer surface, making continuous operation difficult.
X (3): The formation of the surface layer was poor, and the basis weight and paper thickness profiles deteriorated.
Δ (4): Water-soluble polymer wrinkles adhered to the calender equipment for applying the water-soluble polymer to the surface, and defects were generated on the paper surface.
[0043]
[Example 2]
A dust-free paper was obtained in the same manner as in Example 1 except that the mixing ratio of the pulp fiber and the hot melt fiber in the intermediate layer was changed to 30 parts NBKP, 60 parts LBKP, and 10 parts hot melt fiber “M7007”. The obtained dust-free paper was measured and evaluated in the same manner as in Example 1. The results are shown in Table 1.
[0044]
Example 3
A dust-free paper was obtained in the same manner as in Example 1 except that the blending ratio of the pulp fiber and the hot-melt fiber in the intermediate layer was 20 parts NBKP, 35 parts LBKP, and 45 parts hot-melt fiber “M7007”. The obtained dust-free paper was measured and evaluated in the same manner as in Example 1. The results are shown in Table 1.
[0045]
Example 4
The thickness of the surface layer and the back layer is 40 μm and the basis weight is 30 g / m.2Except that, dust-free paper was obtained in the same manner as in Example 1. The obtained dust-free paper was measured and evaluated in the same manner as in Example 1. The results are shown in Table 1.
[0046]
Example 5
The thickness of the surface layer and the back layer is 120 μm and the basis weight is 90 g / m.2Except that, dust-free paper was obtained in the same manner as in Example 1. The obtained dust-free paper was measured and evaluated in the same manner as in Example 1. The results are shown in Table 1.
[0047]
Example 6
The amount of polyvinyl alcohol applied to the front and back layers is 0.2 g / m, respectively.2A dust-free paper was obtained in the same manner as in Example 1 except that the aqueous solution concentration was 0.5%. The obtained dust-free paper was measured and evaluated in the same manner as in Example 1. The results are shown in Table 1.
[0048]
Example 7
The amount of polyvinyl alcohol applied to the front and back layers is 1.0 g / m, respectively.2A dust-free paper was obtained in the same manner as in Example 1 except that the aqueous solution concentration was 5.0%. The obtained dust-free paper was measured and evaluated in the same manner as in Example 1. The results are shown in Table 1.
[0049]
Example 8
Dust-free paper was obtained in the same manner as in Example 1 except that the hot-melt fiber was trade name “UL410” (manufactured by Mitsui Chemicals, Inc., melting point 135 ° C.). The obtained dust-free paper was measured and evaluated in the same manner as in Example 1. The results are shown in Table 1.
The dust-free papers of Examples 1 to 8 had a small dust generation amount in any dust generation test of rubbing, stagnation, and tearing and satisfy the quality as dust-free paper. In addition, it has excellent workability such as printability, blade dirt during cutting, and stickiness on the surface, which eliminates the problems of conventional dust-free paper.
[0050]
[Comparative Example 1]
A paper was obtained in the same manner as in Example 1 except that the mixing ratio of the pulp fiber and the hot melt fiber in the intermediate layer was changed to 35 parts NBKP, 62 parts LBKP, and 3 parts hot melt fiber “M7007”. The obtained paper was measured and evaluated in the same manner as in Example 1. The results are shown in Table 1.
The obtained paper had a large amount of paper dust generated from the paper cross section in the tear and tear test, and was not suitable as a dust-free paper.
[0051]
[Comparative Example 2]
A paper was obtained in the same manner as in Example 1 except that the blending ratio of the pulp fiber and the hot-melt fiber in the intermediate layer was 15 parts NBKP, 25 parts LBKP, and 60 parts hot-melt fiber “M7007”. The obtained paper was measured and evaluated in the same manner as in Example 1. The results are shown in Table 1.
The obtained paper became a paper with a non-uniform texture called floc during paper making, and it was difficult to adjust the basis weight and paper thickness, and stable operation was impossible.
[0052]
[Comparative Example 3]
A paper was obtained in the same manner as in Example 1 except that the hot-melt fiber was trade name “E790” manufactured by Mitsui Chemicals, Inc. and the melting point was 150 ° C. The obtained paper was measured and evaluated in the same manner as in Example 1. The results are shown in Table 1.
The obtained paper had a large amount of paper dust generated from the paper cross section in the tear and tear test, and was not suitable as a dust-free paper.
[0053]
[Comparative Example 4]
The thickness of the surface layer and the back layer is 20 μm each, and the basis weight is 15 g / m.2The thickness of the intermediate layer is 360 μm, and the basis weight is 290 g / m.2The total thickness is 400 μm and the basis weight is 320 g / m.2A paper was obtained in the same manner as in Example 1 except that. The obtained paper was measured and evaluated in the same manner as in Example 1. The results are shown in Table 1.
The paper obtained was melted and adhered to the surface of the dryer during paper making by melting the hot-melt fiber blended in the intermediate layer, resulting in significant dirt, making operation difficult.
[0054]
[Comparative Example 5]
The thickness of the surface layer and the back layer is 160 μm and the basis weight is 125 g / m.2The thickness of the intermediate layer is 80 μm and the basis weight is 50 g / m.2The total thickness is 400 μm and the basis weight is 320 g / m.2A paper was obtained in the same manner as in Example 1 except that. The obtained paper was measured and evaluated in the same manner as in Example 1. The results are shown in Table 1.
Since the obtained paper had a thin intermediate layer, the content of hot melt fibers was small, and the amount of paper dust generated from the paper cross section in the stagnation and tearing sag test was large, which was unsuitable as dust-free paper.
[0055]
[Comparative Example 6]
The amount of polyvinyl alcohol applied to the surface layer and the back layer is 0.05 g / m, respectively.2A paper was obtained in the same manner as in Example 1 except that the aqueous solution concentration was 0.25%. The obtained paper was measured and evaluated in the same manner as in Example 1. The results are shown in Table 1.
The obtained paper had a large amount of paper dust generated from the paper surface in the rubbing and stagnation tests, and was not suitable as a dust-free paper.
[0056]
[Comparative Example 7]
The amount of polyvinyl alcohol applied to the front and back layers is 1.3 g / m, respectively.2A paper was obtained in the same manner as in Example 1 except that the aqueous solution concentration was 6.0%. The obtained paper was measured and evaluated in the same manner as in Example 1. The results are shown in Table 1.
The obtained paper had poor ink fixability during offset printing and poor print quality, and could not solve the problems of conventional dust-free paper.
[0057]
[Comparative Example 8]
Measurement and evaluation were performed in the same manner as in Example 1 using commercially available dust-free paper (trade name “STAKLIN”, manufactured by Lintec Corporation). The results are shown in Table 1.
Although this dust-free paper produces a good amount of paper dust from the paper surface and cross-section, it has poor ink fixability during offset printing and poor print quality, and the paper surface is not sticky during cutting, which improves workability. There was a problem.
[0058]
[Comparative Example 9]
Measurement and evaluation were performed in the same manner as in Example 1 using commercially available dust-free paper (trade name “OK CLEAN” manufactured by Oji Paper Co., Ltd.). The results are shown in Table 1.
Although this dust-free paper produces a good amount of paper dust from the paper surface and cross-section, it has poor ink fixability during offset printing and poor print quality, and the paper surface is not sticky during cutting, which improves workability. There was a problem.
[0059]
[Table 1]
【The invention's effect】
As described above in detail, the dust-free paper of the present invention has reduced dust generation and excellent workability during production.
Claims (4)
前記中間層のみに融点１４０℃以下の熱溶融性繊維を５〜５０重量％の範囲で配合し、
前記表面層及び前記裏面層のそれぞれに水溶性高分子を主成分とする水溶液を０．１〜１．０ｇ／ｍ2塗工してなり、
前記表面層及び前記裏面層の厚さは、３０〜１２０μｍであり、坪量は、２５〜１００ｇ／ｍ2で、前記中間層の厚さは、５０〜９００μｍであり、坪量は、４０〜７００ｇ／ｍ 2 で、前記無塵紙の全体の厚さは、１００〜１１００μｍであり、坪量は、９０〜９００ｇ／ｍ 2 である、
ことを特徴とする無塵紙。It comprises at least three layers of a surface layer, a back surface layer, and an intermediate layer located between both layers . After combining the surface layer, the back surface layer, and the intermediate layer, it is brought into contact with the dryer surface and dried. Dust-free paper
Only the intermediate layer is blended in the range of 5 to 50% by weight of a hot-melt fiber having a melting point of 140 ° C. or less,
Each of the surface layer and the back surface layer is coated with 0.1 to 1.0 g / m 2 of an aqueous solution containing a water-soluble polymer as a main component,
The thickness of the surface layer and the back layer is 30 to 120 μm, the basis weight is 25 to 100 g / m 2 , the thickness of the intermediate layer is 50 to 900 μm, and the basis weight is 40 to 40 μm. 700 g / m 2 , the entire thickness of the dust-free paper is 100 to 1100 μm, and the basis weight is 90 to 900 g / m 2 .
Dust-free paper characterized by that .
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP2003092202A JP4184848B2 (en) | 2003-03-28 | 2003-03-28 | Dustless paper |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP2003092202A JP4184848B2 (en) | 2003-03-28 | 2003-03-28 | Dustless paper |
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| Publication Number | Publication Date |
|---|---|
| JP2004300587A JP2004300587A (en) | 2004-10-28 |
| JP2004300587A5 JP2004300587A5 (en) | 2006-04-20 |
| JP4184848B2 true JP4184848B2 (en) | 2008-11-19 |
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| Application Number | Title | Priority Date | Filing Date |
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| JP2003092202A Expired - Fee Related JP4184848B2 (en) | 2003-03-28 | 2003-03-28 | Dustless paper |
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| Country | Link |
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| JP (1) | JP4184848B2 (en) |
Families Citing this family (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2009057668A (en) * | 2007-09-03 | 2009-03-19 | National Printing Bureau | Multi-ply paper and method for producing the same |
| JP5215923B2 (en) * | 2009-04-10 | 2013-06-19 | 北越紀州製紙株式会社 | Low dust generation paper |
| JP7069260B2 (en) * | 2020-08-20 | 2022-05-17 | 大王製紙株式会社 | Coated paper for tableware and paper tableware |
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2003
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| JP2004300587A (en) | 2004-10-28 |
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