【発明の詳細な説明】[Detailed description of the invention]
本発明は感光性印刷版材用合紙に関するもので
ある。更に詳細には、感光性印刷版にすぐれた裁
断性を与え、感光性印刷版の保護能力にすぐれ、
更に裁断後における感光性印刷版との分離が容易
な合紙に関するものである。
感光性印刷版材、特にアルミニウム、鉄、亜鉛
等の金属を支持体とした平版用又は凸版用感光性
印刷版材を包装する場合、印刷版材を数枚から数
10枚積重ねて一単位の包装にする方法が一般に行
なわれている。この場合、重ねられた感光性印刷
版材が相互に摩擦して感光面を損傷することがあ
る。又、数10枚の感光性印刷版材をギロチンで一
定寸法に裁断する場合、金属を支持体とした感光
性印刷版材のみ（即ち、合紙を使用しない場合）
では、ほとんど裁断できず、ギロチン刃が損傷
し、印刷版材の切断面が鏡面状態にならず、凹凸
のギザギザ状態になりギロチン刃を頻繁に交換し
なければならない。
この様に、摩擦損傷から感光性印刷版材面を保
護するためと、ギロチンでの感光性印刷版材裁断
時にギロチン刃の損傷をおさえ、同一ギロチン刃
での感光性印刷版材の裁断回数を延長させる、即
ち裁断性を向上させる為に、従来、感光性印刷版
材の感光層より柔らかな材質のシートを相互に隣
接する２枚の感光性印刷版材間に挾み込んでい
る。
その様な目的に用いる素材を一般に合紙と呼
び、従来、紙や不織布やプラスチツクシート又は
フイルムや両面に合成樹脂をプレコート及びラミ
ネートした紙シートが用いられている。これ等の
合紙を用いる主なる第１の目的は上に記した様
に、引掻き又は摩擦による感光性印刷版材の感光
層の損傷を防ぐためである。第２の目的は、数10
枚積み重ねた感光性印刷版材をギロチンで裁断す
る際の裁断性を向上させるためである。
天然パルプより成る一般の紙を合紙に用いた場
合は充分な裁断性が得られない為、プラスチツク
シート、フイルム、又は両面に合成樹脂をプレコ
ート及びラミネートしたシートを感光性印刷版材
用合紙として用いていた。しかし、この様なプラ
スチツクシートは感光性印刷版材との密着が良す
ぎて、感光性印刷版材を使用する際、容易にはが
しにくい欠点があり強い力でシートをはがすため
版材の感光層が損傷し感光性印刷版材の平滑性が
悪くなる等の欠点があつた。
又この様なプラスチツクシートと感光性印刷版
材とを密着させる工程でシートと版材の間に空気
が溜り抜けない為、ロールで密着強化する時等に
シートがシワになり印刷版材の感光層が損傷する
欠点があつた。
又天然パルプより成る紙に比べコストが高い欠
点があつた。さらに廃棄物としての処理が面倒で
あるという欠点もあつた。
本発明者らは、上述のような従来の感光性印刷
版材用合紙の欠点を解決すべく、鋭意研究した結
果、紙にワツクスを含有させることにより、従来
の天然パルプより成る紙に比べ、著しく裁断性を
向上させ、かつ、プラスチツクシートに比べ、感
光性印刷版材の使用時に容易にはがすことの出来
る感光性印刷版材用合紙を得られる事を見出し本
発明を完成するに至つた。すなわち本発明は紙に
ワツクスを固型分量0.03〜10％含有したことを特
徴とする感光性印刷版材用合紙である。
本発明に用いるワツクスとしては動物系ワツク
ス、植物系ワツクス及び石油系ワツクス（即ちパ
ラフインワツクス）を使用できる。特に本発明の
裁断性に優れた印刷版材用合紙として用いるワツ
クスとしては動物系及び、植物系ワツクスが好ま
しい。さらに上記ワツクス単独の外、ワツクスに
石油樹脂系の各種合成樹脂をワツクス分散液の安
定性を向上させる目的で混合したものも使用でき
る。
本発明に使用するワツクス及びワツクス混合物
としては、融点が40〜140℃のものが好ましく、
特に55〜100℃のものが好ましい。融点が40℃よ
り低いと合紙の製造中の乾燥時に溶融する等の工
程汚れが生じやすく、さらに運送中の高温時にワ
ツクスが溶出する等の問題が生じてしまう。融点
が140℃より高くなると裁断性向上の効果が劣つ
てしまう。
本発明に用いるワツクスは界面活性剤により水
溶液中に容易に分散出来るワツクス分散液の状態
が望ましく、界面活性剤としてはアニオン、ノニ
オン、カチオンのいずれの界面活性剤も使用する
ことができる。
さらに本発明のワツクス含有合紙を作る場合、
紙料構成としては木材パルプ、麻等の天然繊維の
みならず、ポリオレフイン等の線状高分子から得
られる合成パルプや、合成繊維や再生セルロース
を混合することができる。
さらに通常の製紙に用いられる他の添加剤を加
えることができる。例えば、粘度、タルク、チタ
ンホワイトのような充填剤や、ロジン、合成サイ
ズのようなサイズ剤や、メラミン樹脂又はポリア
ミド、ポリアミンエピクロルヒドリン樹脂のよう
な湿潤強度向上剤や澱粉やポリアクリルアミドの
ような乾燥強度向上剤を加えることができる。さ
らに、上に記した充填剤、サイズ剤等の定着剤と
して硫酸アルミニウム等の水溶性多価金属塩又
は、カチオン性澱粉やカチオン性ポリマー等の定
着剤を加えることができる。
さらに本発明のワツクス含有を表面サイズ法で
行なう場合、ワツクス分散液単独や、澱粉、ポリ
ビニルアルコール、ゼラチン等の水溶性高分子を
併用する事ができる。水溶性高分子の併用はワツ
クス分散液の撹拌等の機械的安定性を増し、製造
安定化に効果がある。水溶性高分子の併用量とし
てはワツクス１重量部当り0.5〜４重量部が適量
である。
本発明のワツクス含有の感光性印刷版材用合紙
を作成する方法としては紙料中にワツクスを添加
し、紙料にワツクスを定着させた後、長網抄紙
機、円網抄紙機で抄造する内添法と、抄紙機のサ
イズプレス又はカレンダーで紙の表面にワツクス
を含浸する表面サイズ法と紙にグラビアロール
や、塗布バーでワツクスを塗布する方法を用いる
ことができる。
本発明の第１の目的である印刷版材の裁断性向
上のためには、上記の表面サイズ法により、ワツ
クスを紙の表面に含有させる方法が最も効果が良
く、0.03〜1.5％の少量のワツクス含有量でも効
果があり、内添法より低コストで製造できる。
又、製造工程も簡単で安価であり、表面サイズ法
が最も好ましい方法である。
本発明に用いるワツクスの含有量としてはワツ
クス固型分として0.03〜10％が好ましく特にワツ
クス固型分として0.07〜2.5％が特に好ましい。
ワツクス含有量が0.03％以下では印刷版材の裁断
性向上効果がなく、ワツクス含有量が５％以上に
なると合紙が著しく滑り易くなり、印刷版材と合
紙間で滑り過ぎ、工程上の問題となる。
本発明のワツクス含有合紙を表面サイズ法で作
る場合は特に0.07〜2.0％が好ましい。
本発明におけるワツクス含有合紙が金属支持体
の感光性印刷版材の裁断性を向上させる理由は定
かでないが、おそらくワツクスがギロチン刃の潤
滑剤的役割りを果し裁断性を向上していると推定
される。
以上の様に本発明は紙にワツクスをワツクス固
型分として0.03〜10％含有した感光性印刷版材用
合紙を用いることにより、ワツクスを含有して
いない天然パルプからなる合紙よりも感光性印刷
版材の裁断性を著しく向上させることができる。
又、感光性印刷版材を使用する際に合紙が容易
にはがれ、従来のプラスチツクシートの合紙のよ
うな感光層を損傷することなく使用できる。
又、感光性印刷版材と合紙を密着させる工程で印
刷版材と合紙との間に空気の溜りが起きない為、
合紙がシワになる事がなく印刷版材の感光層を損
傷する事がない。さらに、プラスチツクシート
に比べ経済的利点が大きいなどの効果が得られ
る。
かくの如く、従来未解決であつた感光性印刷版
材用合紙の問題点を解決することが出来た。
以下具体的な実施例により本発明を更に詳しく
説明する。
実施例 １
漂白クラフトパルプ50重量部と漂白サルフアイ
トパルプ50重量部の混合紙料を50°SRまで叩解
し３％の濃度に希釈した紙料にロジンサイズを固
型分として１重量部加え、充分撹拌後、硫酸アル
ミニウムをpHが4.5になるまで加え、長網抄紙機
で抄造しサイズプレスでワツクス分散液（融点80
℃のワツクスをポリオキシ−エチレン−モノ−エ
チルエーテルでワツクス固型分２％に分散したワ
ツクス分散液）を塗布量として15c.c./m2表面サイ
ズし、80〜90℃で乾燥後45ｇ/m2の感光性印刷版
材用合紙を作成した。これをシート（）とす
る。
感光性印刷版材としてはアルミニウム板にジア
ゾ樹脂を塗布した市販の感光性印刷版材を用い
た。
上記感光性印刷版材と合紙とを密着させシート
に切断し、裁断性テスト、剥離性テストを行つ
た。
結果は第１表にまとめる。
比較例 １−１
ワツクス分散液による表面サイズを行なわない
以外は実施例１と同じ方法で合紙を作成した。こ
れをシート（−１）とする。
比較例 １−２
シート（−１）作成後、溶融押出機から押出
された300℃の低密度ポリエチレン溶融物の20μ
薄膜でシート（−１）を両面ラミネートした合
紙を作つた。これをシート（−２）とする。
The present invention relates to interleaf paper for photosensitive printing plate materials. More specifically, it provides excellent cuttability to photosensitive printing plates, has excellent protection ability for photosensitive printing plates,
Furthermore, the present invention relates to interleaf paper that can be easily separated from the photosensitive printing plate after cutting. When packaging photosensitive printing plate materials, especially photosensitive printing plate materials for planography or letterpress using metals such as aluminum, iron, zinc, etc. as a support, it is necessary to package photosensitive printing plates from several sheets to several sheets.
A commonly used method is to stack 10 sheets into one unit of packaging. In this case, the stacked photosensitive printing plate materials may rub against each other and damage the photosensitive surface. In addition, when cutting several dozen photosensitive printing plates to a certain size using a guillotine, only photosensitive printing plates with a metal support (that is, when no interleaving paper is used)
In this case, cutting is almost impossible, the guillotine blade is damaged, and the cut surface of the printing plate material is not mirror-like, but has a jagged, uneven surface, and the guillotine blade must be replaced frequently. In this way, in order to protect the surface of the photosensitive printing plate material from friction damage, and to suppress damage to the guillotine blade when cutting the photosensitive printing plate material with the guillotine, it is possible to reduce the number of times the photosensitive printing plate material is cut with the same guillotine blade. In order to extend the length, that is, to improve cuttability, conventionally, a sheet made of a material softer than the photosensitive layer of the photosensitive printing plate material is sandwiched between two adjacent photosensitive printing plate materials. Materials used for such purposes are generally called interleaf paper, and conventionally used are paper, nonwoven fabric, plastic sheets, films, and paper sheets precoated and laminated with synthetic resin on both sides. As stated above, the primary purpose of using these interleaving papers is to prevent damage to the photosensitive layer of the photosensitive printing plate material due to scratching or friction. The second purpose is the number 10
This is to improve cutting performance when cutting stacked photosensitive printing plates with a guillotine. If ordinary paper made of natural pulp is used as interleaving paper, sufficient cutting properties cannot be obtained, so plastic sheets, films, or sheets pre-coated and laminated with synthetic resin on both sides are used as interleaving paper for photosensitive printing plates. It was used as. However, such plastic sheets adhere too well to the photosensitive printing plate material, so when using the photosensitive printing plate material, it is difficult to peel it off easily. There were disadvantages such as damage to the photosensitive printing plate material and poor smoothness of the photosensitive printing plate material. In addition, in the process of bringing the plastic sheet and the photosensitive printing plate into close contact, air does not accumulate between the sheet and the plate, so when the adhesion is strengthened with a roll, the sheet wrinkles and the photosensitive printing plate material deteriorates. The problem was that the layers were damaged. Another drawback is that it is more expensive than paper made from natural pulp. Another drawback was that it was troublesome to dispose of it as waste. In order to solve the above-mentioned drawbacks of the conventional interleaving paper for photosensitive printing plates, the inventors of the present invention have conducted intensive research and found that by incorporating wax into the paper, the paper has a higher quality than conventional paper made of natural pulp. They found that it was possible to obtain interleaving paper for photosensitive printing plates that has significantly improved cutting properties and is easier to peel off when using photosensitive printing plates than plastic sheets, leading to the completion of the present invention. Ivy. That is, the present invention is an interleaf paper for photosensitive printing plates, characterized in that the paper contains wax in a solid content of 0.03 to 10%. As the wax used in the present invention, animal-based waxes, plant-based waxes, and petroleum-based waxes (ie, paraffin waxes) can be used. In particular, animal-based and vegetable-based waxes are preferable as the wax used as interleaf paper for printing plate materials having excellent cuttability in the present invention. Furthermore, in addition to the above-mentioned wax alone, it is also possible to use wax mixed with various petroleum resin-based synthetic resins for the purpose of improving the stability of the wax dispersion. The wax and wax mixture used in the present invention preferably have a melting point of 40 to 140°C,
Particularly preferred is a temperature of 55 to 100°C. If the melting point is lower than 40°C, problems such as melting during drying during the production of interleaf paper tend to occur during the process, and problems such as wax elution at high temperatures during transportation occur. If the melting point is higher than 140°C, the effect of improving cuttability will be poor. The wax used in the present invention is preferably in the form of a wax dispersion that can be easily dispersed in an aqueous solution using a surfactant, and any anionic, nonionic, or cationic surfactant can be used as the surfactant. Furthermore, when making the wax-containing interleaving paper of the present invention,
As for the paper material composition, not only natural fibers such as wood pulp and hemp, but also synthetic pulp obtained from linear polymers such as polyolefin, synthetic fibers, and regenerated cellulose can be mixed. Additionally, other additives used in conventional papermaking can be added. For example, fillers such as viscosity, talc, titanium white, sizing agents such as rosin, synthetic sizes, wet strength agents such as melamine resins or polyamides, polyamine epichlorohydrin resins, and drying agents such as starch or polyacrylamide. Strength enhancers can be added. Furthermore, a water-soluble polyvalent metal salt such as aluminum sulfate, or a fixing agent such as cationic starch or cationic polymer can be added as a fixing agent such as the filler and sizing agent described above. Furthermore, when the wax of the present invention is incorporated by the surface size method, a wax dispersion alone or a water-soluble polymer such as starch, polyvinyl alcohol, gelatin, etc. can be used in combination. The combined use of a water-soluble polymer increases the mechanical stability of the wax dispersion during stirring, etc., and is effective in stabilizing production. The appropriate amount of water-soluble polymer used in combination is 0.5 to 4 parts by weight per 1 part by weight of wax. The method for producing the wax-containing interleaving paper for photosensitive printing plate materials of the present invention is to add wax to the paper stock, fix the wax to the paper stock, and then make the paper using a Fourdrinier paper machine or cylinder paper machine. An internal addition method, a surface size method in which the surface of the paper is impregnated with wax using a size press or a calendar of a paper machine, and a method in which wax is applied to the paper using a gravure roll or a coating bar can be used. In order to improve the cuttability of printing plate materials, which is the first objective of the present invention, it is most effective to incorporate wax on the surface of the paper using the above-mentioned surface size method. It is effective even with wax content, and can be manufactured at a lower cost than the internal addition method.
In addition, the manufacturing process is simple and inexpensive, and the surface size method is the most preferred method. The content of the wax used in the present invention is preferably 0.03 to 10% as a wax solid content, and particularly preferably 0.07 to 2.5% as a wax solid content.
If the wax content is less than 0.03%, there will be no effect on improving the cuttability of the printing plate material, and if the wax content is more than 5%, the interleaving paper will become extremely slippery, causing too much slippage between the printing plate material and the interleaving paper, and causing problems in the process. It becomes a problem. When the wax-containing interleaving paper of the present invention is made by the surface size method, the content is particularly preferably 0.07 to 2.0%. The reason why the wax-containing interleaving paper of the present invention improves the cuttability of the photosensitive printing plate material having a metal support is not clear, but it is likely that the wax acts as a lubricant for the guillotine blade and improves the cuttability. It is estimated to be. As described above, the present invention uses interleaf paper for photosensitive printing plates containing 0.03 to 10% of wax as a wax solid content, thereby making it more photosensitive than interleaf paper made of natural pulp that does not contain wax. The cuttability of printing plate materials can be significantly improved.
Further, when using the photosensitive printing plate material, the interleaving paper is easily peeled off, and the photosensitive layer can be used without damaging the photosensitive layer, which is the case with the interleaving paper of conventional plastic sheets.
In addition, in the process of bringing the photosensitive printing plate material and the interleaving paper into close contact, no air is trapped between the printing plate material and the interleaving paper.
The interleaving paper does not wrinkle and the photosensitive layer of the printing plate material is not damaged. Furthermore, it has greater economical advantages than plastic sheets. In this way, it has been possible to solve the problems of interleaving paper for photosensitive printing plates, which had hitherto been unsolved. The present invention will be explained in more detail below using specific examples. Example 1 A mixed paper stock of 50 parts by weight of bleached kraft pulp and 50 parts by weight of bleached sulfite pulp was beaten to 50° SR and diluted to a concentration of 3%, and 1 part by weight of rosin size was added as a solid content to the stock. After stirring thoroughly, aluminum sulfate was added until the pH reached 4.5, paper was made using a Fourdrinier machine, and a wax dispersion (melting point 80
℃ wax dispersed with polyoxy-ethylene-mono-ethyl ether (wax dispersion with wax solid content of 2 % ) was coated to a surface size of 15 c.c./m2, and after drying at 80 to 90℃, 45 g/m2 was applied. An interleaving paper for photosensitive printing plate material of 2 m2 was prepared. Let this be sheet (). A commercially available photosensitive printing plate material made of an aluminum plate coated with a diazo resin was used as the photosensitive printing plate material. The above-mentioned photosensitive printing plate material and interleaf paper were brought into close contact with each other and cut into sheets, and a cutability test and a peelability test were conducted. The results are summarized in Table 1. Comparative Example 1-1 An interleaving paper was prepared in the same manner as in Example 1, except that the surface sizing using the wax dispersion was not carried out. This is called sheet (-1). Comparative Example 1-2 After sheet (-1) was created, 20μ of low density polyethylene melt at 300°C was extruded from a melt extruder.
An interleaving paper was made by laminating the sheet (-1) on both sides with a thin film. This is called sheet (-2).
【表】
(1) 裁断性テストは500mm巾の感光性印刷版材と
合紙を交互に50枚積み重ねギロチンで切断し切
断面が何回迄鏡面状態で切断できるかテストし
た。
(2) 剥離性テストは1000mm×800mmの感光性印刷
版材と合紙を圧着し、交互に2000枚積み重ねて
１週間放置后、下段の感光性印刷版材と合紙を
取り出し、合紙のはがし易さをテストした。
第１表の結果に見られる如く、本発明の合紙は
感光性印刷版材の裁断性に優れ、かつ、感光性印
刷版材を使用する際に感光性印刷版材の感光層を
損傷することなく容易に合紙をはがせる。又、感
光性印刷版材と合紙を密着させる工程で感光性印
刷版材との間に空気が溜まる事なく、合紙がシワ
にならない為、印刷版材の感光層を損傷すること
がない。以上の様に本発明の合紙が、感光性印刷
版材用合紙として優れている事が分かる。[Table] (1) Cutting performance test was performed by stacking 50 sheets of 500 mm wide photosensitive printing plates and interleaf paper alternately and cutting them with a guillotine to see how many times the cut surface could be cut with a mirror finish. (2) For the peelability test, 1000mm x 800mm photosensitive printing plates and interleaving paper were pressed together, 2000 sheets were stacked alternately and left for one week, then the lower photosensitive printing plate and interleaving paper were removed and the interleaving paper was The ease of peeling was tested. As can be seen from the results in Table 1, the interleaving paper of the present invention has excellent cutting properties for photosensitive printing plates, and does not damage the photosensitive layer of the photosensitive printing plates when used. The paper can be easily peeled off without any problems. In addition, in the process of bringing the photosensitive printing plate material and interleaving paper into close contact, air does not accumulate between the photosensitive printing plate material and the interleaving paper does not wrinkle, so the photosensitive layer of the printing plate material is not damaged. . As described above, it can be seen that the interleaving paper of the present invention is excellent as an interleaving paper for photosensitive printing plate materials.