JP4357194B2 - Thermal recording paper - Google Patents

Description

【００５７】
（参考実施例１）
＜樹脂フィルム（Ａ）＞
ＰＰ（表１に記載）３０重量％とＨＳＢＲ（表１に記載）５０重量％との混合物に、炭カル（表１に記載）２０重量％を配合した組成物［○１］を、２５０℃に設定した押出機にて混練し、ストランド状に押出し、カッティングしてペレットとした。この組成物［○１］を２５０℃に設定した押出機に接続したＴダイよりフィルム状に押出し、これを冷却装置により冷却して無延伸フィルムを得た（厚み：１００μｍ、結晶化熱：２９Ｊ／ｃｍ³ ）。
【００５８】
このフィルムの両面に、印加エネルギー密度１００Ｗ・分／ｍ² にてコロナ放電処理を行った。
尚、各実施例及び比較例中の樹脂成分ないしはこれと微細粉末との混合物の溶融混練において、樹脂成分と微細粉末の合計重量を１００重量部として、これに加えて、酸化防止剤として、ＢＨＴ（４−メチル−２，６−ジ−ｔ−ブチルフェノール）０．２重量部と、イルガノックス１０１０（フェノール系酸化防止剤、チバガイギー社製、商品名）０．１重量部を添加した。
また、本明細書の実施例に使用した炭酸カルシウム粉末の粒子径は、レーザー回折式粒子計測装置「マイクロトラック」（（株）日機装製、商品名）により測定した累積５０％粒径である。
【００５９】
＜画像記録層（Ｂ）の形成＞
下記成分からなる直接感熱記録層形成組成物を樹脂フィルム（Ａ）に塗工して、乾燥時の厚さ１０μｍの画像記録層（Ｂ）を形成した。

この比率の組成物をサンドグラインダーで平均粒径２μｍまで粉砕する。
【００６０】

この比率の組成物をサンドグラインダーで平均粒径２μｍまで粉砕する。
Ａ液２５重量部、Ｂ液１８０重量部、タルク５０％水分散液７０重量部及びバインダーとしてヒドロキシエチルセルロース５％水溶液２４０重量部を混合した。
このものにつき、以下の要領で評価を行った。評価結果を表２にまとめて示す。
【００６１】
＜評価＞
ｉ．カール高さの評価
得られた本発明の感熱記録用紙をＡ−４サイズ（２１０ｍｍ×２９７ｍｍ）に断裁し、温度２３℃、相対湿度５０％の恒温恒湿室内で１日間放置した。次に、市販の直接感熱記録プリンター「ＭＵＬＴＩＳＣＡＮ ＶＩＤＥＯ ＰＲＩＮＴＥＲ ＵＰ−９３０」（ＳＯＮＹ製、商品名）によって、画像記録層（Ｂ）を印刷面とした通紙経路で、黒ベタ印刷を行った。
プリンターの通紙後、感熱記録用紙を湿度２３℃、相対湿度５０％の雰囲気下、平らな台の上に放置し、通紙２分後の４隅のカール高さを評価した。
【００６２】
ii．印刷品質の評価
印刷後の黒ベタ部の印刷濃度について、目視観察し、以下の基準で評価した。
非常に良好（◎）濃度ムラが無い。（実使用可能）
良好（○）濃度ムラが少しある。（実使用可能）
不良（×）濃度ムラがある。（実使用困難）
iii ．耐水強度の評価
得られた感熱記録用紙を５０ｍｍ×５０ｍｍの正方形に断裁し、２０℃の水に１日間浸水させた後、フィルムを手で引き裂いたとき状態について、以下の基準で評価した。
非常に良好（◎）基材が破れない。（実使用可能）
良好（○）基材が容易には破れない。（実使用可能）
不良（×）基材が容易に破れる。（実使用困難）
【００６３】
（参考実施例２）
組成物［○２］の配合成分の種類及び量を表２記載のものとしたほかは、参考実施例１と同様の操作により感熱記録用紙を作製し、評価を行った。評価結果を表２に示す。
（参考実施例３）
組成物［○３］の配合成分の種類及び量を表２記載のものとし、参考実施例１と同様の操作により無延伸フィルムを得た後、この無延伸フィルムを１４５℃（温度ａ）に加熱した後、縦方向に５倍延伸して延伸フィルムを得た（厚み：１００μｍ、結晶化熱：３７Ｊ／ｃｍ³ ）。その後、参考実施例１と同様の操作により感熱記録用紙を作製し、評価を行った。評価結果を表２に示す。
【００６４】
（実施例４）
組成物［○４］の配合成分の種類及び量を表２記載のものとし、参考実施例１と同様の操作により無延伸フィルムを得た後、この無延伸フィルムを１４０℃（温度ａ）に加熱した後、縦方向に５倍延伸して延伸フィルムを得た。
組成物［○４］を２４０℃に設定した押出機に接続したＴダイよりフィルム状に押出した。得られたフィルムを上記の操作により調製した５倍延伸フィルムの両面に積層し、５５℃にまで冷却した後、１６０℃（温度ｂ）に加熱してテンターで横方向に８倍延伸した。その後、１６５℃（温度ｃ）でアニーリング処理し、５０℃にまでに冷却し、耳部をスリットして３層構造（１軸延伸／２軸延伸／１軸延伸）のフィルムを得た（厚み：１５／７０／１５μｍ＝１００μｍ、結晶化熱：４１Ｊ／ｃｍ³ ）。その後、参考実施例１と同様の操作により感熱記録用紙を作製し、評価を行った。評価結果を表２に示す。
【００６５】
（実施例５）
組成物［○５］の配合成分の種類及び量を表２記載のものとし、２５０℃に設定された２台の異なる押出機が接続された多層ダイを用い、３層構造になるようダイ内で積層されるようにしてフィルム状に押出し、これを冷却装置により冷却して無延伸フィルムを得た。
次いで、この無延伸フィルムを１４０℃（温度ａ）に加熱した後、縦方向に５倍延伸したのち冷却し、延伸フィルムを得た。
再度、１６３℃（温度ｂ）に加熱してテンターで横方向に８倍延伸した。その後、１６８℃（温度ｃ）でアニーリング処理し、５０℃にまでに冷却し、耳部をスリットして３層構造（２軸延伸／２軸延伸／２軸延伸）のフィルムを得た（厚み：１５／７０／１５μｍ＝１００μｍ、結晶化熱：４１Ｊ／ｃｍ³ ）。その後、参考実施例１と同様の操作により感熱記録用紙を作製し、評価を行った。評価結果を表２に示す。
【００６６】
（比較例１）
組成物［○６］の配合成分の種類及び量を表２記載のものとしたほかは、参考実施例１と同様の操作により感熱記録用紙を作製し、評価を行った。評価結果を表２に示す。
（比較例２）
組成物［○７］の配合成分の種類及び量を表２記載のものとしたほかは、実施例５と同様の操作により感熱記録用紙を作製し、評価を行った。評価結果を表２に示す。
（比較例３）
市販のパルプ紙「マイリサイクルペーパー１００ｗ」（（株）ＮＢＳリコー、商品名）を用いて、参考実施例１と同様の操作による画像記録層を形成したものを作製し、評価を行った。評価結果を表２に示す。
【００６７】
【表２】

【００６８】
（参考実施例６）
組成物［○８］の配合成分の種類及び量を表３記載のものとし、層間剥離を可能とする層（Ｃ）としての組成物［○８］と樹脂フィルム（Ａ）としての組成物［○３］とを２５０℃に設定された２台の異なる押出機が接続された多層ダイを用い、２層構造になるようダイ内で積層されるようにしてフィルム状に押出し、これを冷却装置により冷却して無延伸フィルムを得た。
次いで、この無延伸フィルムを１５０℃（温度ａ）に加熱した後、縦方向に５倍延伸したのち冷却し、延伸フィルムを得た。
再度、１４３℃（温度ｂ）に加熱してテンターで横方向に８倍延伸した。その後、１６０℃（温度ｃ）でアニーリング処理し、５０℃にまでに冷却し、耳部をスリットして２層（（Ｃ）／（Ａ）：肉厚１５／８０μｍ）構造のフィルムを得た（厚み：９５μｍ）。その後、参考実施例１と同様の操作により感熱記録用紙を得た。
【００６９】
《粘着剤塗工》
得られた感熱記録用紙の層間剥離を可能とする層（Ｃ）面に感圧粘着剤「オリバイン ＢＰＳ−１１０９」（東洋インキ化学工業（株）製、商品名）を固形分量で２５ｇ／ｍ² となるようにコンマコーターで塗工、乾燥した。
このものにつき、以下の要領で評価を行った。評価結果を表３にまとめて示す。
【００７０】
＜評価＞
iv．剥離開始性
層間剥離を可能とする層（Ｃ）の剥離強度、及び表面層（Ｄ）の破断強度は、それぞれ上記＜剥離強度＞、及び＜破断強度＞に記載の方法で測定した。
粘着塗工された感熱記録用紙を５ｃｍ×５ｃｍの正方形に切り取り、官製ハガキの上に貼着した後、感熱記録用紙の４辺の内１辺を手で持ち、官製ハガキより引き剥がし、層間剥離を可能とする層（Ｃ）ないしは表面層（Ｄ）の剥離が開始するまでの状態について、以下の基準で評価した。
非常に良好（◎）剥離がすぐに開始する。（実使用可能）
良好（○）剥離が開始するまでに２ｍｍ以上要する。（実使用可能）
やや不良（△）剥離が部分的に開始する。（実使用困難）
不良（×）剥離が開始するまでに１０ｍｍ以上要する。（実使用困難）
【００７１】
ｖ．剥離伝播性
粘着塗工された感熱記録用紙を５ｃｍ×５ｃｍの正方形に切り取り、官製ハガキの上に貼着した後、樹脂フィルム（Ａ）面４辺の内１辺に粘着テープ（ニチバン（株）製、商品名「セロテープ」）を貼り、層間剥離を可能とする層（Ｃ）ないしは表面層（Ｄ）での剥離が開始し易い状態にし、樹脂フィルム（Ａ）を官製ハガキより引き剥がし、層間剥離を可能とする層（Ｃ）ないしは表面層（Ｄ）の伝播状態と剥離力について、目視観察し、以下の基準で評価した。
非常に良好（◎）剥離力が軽く、全面綺麗に伝播する。（実使用可能）
良好（○）剥離力はやや重いが、全面綺麗に伝播する。（実使用可能）
やや不良（△）剥離力が非常に重いが、全面綺麗に伝播する。（実使用困難）
不良（×）全面伝播できずに途中で切れてしまう。（実使用困難）
【００７２】
vi．情報隠蔽性
官製ハガキに文字サイズ１０ポイントのアルファベット２６文字を印字して、粘着塗工された感熱記録用紙をアルファベットの印字面に貼着し、作製フィルムを透して見える文字の隠蔽性について、目視観察し、以下の基準で評価した。
非常に良好（◎）実使用可能。
良好（○）実使用可能。
やや不良（△）実使用困難。
不良（×）実使用困難。
【００７３】
vii ．情報認識性
合成紙「ＶＥＳ８５」（（株）ユポ・コーポレーション製、商品名）にバーコードプンター「Ｂ３０」（（株）テック製、商品名）にてバーコード（ＣＯＤＥ３９）を印字してバーコード読みとり用サンプルを作成した。
粘着塗工された感熱記録用紙を合成紙上のバーコード印字面上に貼り、バーコードを隠蔽したサンプルを１０個作成し、樹脂フィルム（Ａ）を引き剥がした後のバーコードをバーコードリーダー「ＬＡＳＥＲＣＨＥＫ II」（富士電気冷凍機（株）製、商品名）にて読みとり、バーコード認識に成功した回数について、以下の基準で評価した。
非常に良好（◎）１０回成功。（実使用可能）
良好（○）８〜９回成功。（実使用可能）
やや不良（△）２〜７回成功。（実使用困難）
不良（×）成功回数１回以下。（実使用困難）
【００７４】
（参考実施例７）
ＬＤＰＥ（表１に記載）を１８０℃に設定した押出機に接続したＴダイよりフィルム状に押出した。得られたフィルムを実施例６と同様の操作により調製した５倍延伸フィルムの層間剥離を可能とする層（Ｃ）面に積層し表面層（Ｄ）を設け、５５℃にまで冷却した後、１４８℃（温度ｂ）に加熱してテンターで横方向に８倍延伸した。その後、１６２℃（温度ｃ）でアニーリング処理し、５０℃にまでに冷却し、耳部をスリットして３層（（Ｄ）／（Ｃ）／（Ａ）：肉厚５／１５／８０μｍ）構造のフィルムを得た（厚み：１００μｍ）。参考実施例６と同様の操作により感熱記録用紙を作製し、評価を行った。評価結果を表３に示す。
【００７５】
（比較例４）
樹脂フィルム（Ａ）に組成物［▲６▼］（表２に記載）、層間剥離を可能とする層（Ｃ）に組成物［▲９▼］（表３に記載）、表面層（Ｄ）にＥＶＡ（表１に記載）を用い、表３に記載される成形条件以外は、実施例７と同様の操作により感熱記録用紙を作製し、評価を行った。評価結果を表３に示す。
【００７６】
【表３】

【００７７】
【発明の効果】
本発明の感熱記録用紙は、直接感熱型プリンター印刷後のカールを低減させ、多数枚の連続印刷にて良好な印刷性を実現させ、記録された用紙は耐水性、機械特性に優れるので屋内外産業用として有用である。また、剥離を開始するための特殊な加工を必要とせず、小さな力で表面層が剥離するので配送伝表、隠蔽シール、貼り替え防止用ラベル、改ざん防止シール、応募シール、クーポン等の幅広い用途にも有効に利用することができる。[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a thermal recording paper based on a thermoplastic resin film that can be used by a direct thermal recording printer. Furthermore, the present invention is superior in water resistance to natural paper, and is used for poster paper for indoor / outdoor advertising, paper for industrial products (labels with usage instructions and precautionary notes), indoor / outdoor advertising stickers, and frozen foods. The present invention relates to a thermal recording paper suitable for a container label. The present invention also relates to a thermal recording paper that is useful as a base material for a delivery slip having no adhesive residue, a postcard or passbook concealment seal, an anti-paste label, a tamper-proof seal, an application seal, a coupon, etc. by providing a release layer.
[0002]
[Prior art]
Conventionally, heat-sensitive recording paper is configured by forming a heat-sensitive recording layer on one side of a support layer, and is used as an industrial product name label, a label stuck on a frozen food container, or a poster paper for indoor and outdoor advertising. For example, pulp paper or the like has been used as the support layer, but since the water resistance is poor, a resin film with good water resistance, especially polyolefin synthetic paper is used.
Such a resin film is a well-known one, and for details thereof, reference can be made to, for example, each publication of Patent Documents 1 to 5.
[0003]
However, such polyolefin synthetic paper shrinks when heated to 100 ° C. or higher. Therefore, when a direct thermal recording printer having a thermal head temperature of 100 ° C. to 180 ° C. is used for printing, there is a drawback that the printed image is greatly curled toward the inner surface printed by the heat during thermal recording. As a result, there is a problem in that the paper discharge performance is poor, and the continuous printing of a large number of sheets is hindered or cannot be stacked, so that it is difficult to store.
In order to prevent such curling, recording paper (Patent Document 6) in which heat-resistant pulp paper and polyolefin-based synthetic paper are laminated is also used. A processing manufacturer other than the manufacturer purchases both materials and processes them, leading to an increase in the cost of recording paper production. Therefore, it has been strongly desired to provide a recording paper that does not curl only with a film support.
[0004]
Further, an adhesive label for preventing tampering or an adhesive label that cannot be replaced is required and put into practical use. However, these adhesive labels for preventing re-sticking are expensive, and there is a problem that when the label is peeled off, the adhesive remains on the peeled surface and sticks and dust adheres.
References such as Patent Document 7 and Patent Document 8 that solve this problem can be referred to, but there are disadvantages in that water resistance is inferior and special processing such as notches is required to easily start peeling.
[0005]
[Patent Document 1]
Japanese Examined Patent Publication No. 46-40794
[Patent Document 2]
Japanese Patent Publication No.49-1782
[Patent Document 3]
Japanese Patent Laid-Open No. 56-118437
[Patent Document 4]
JP-A-57-12642
[Patent Document 5]
JP-A-57-56224
[Patent Document 6]
JP-A-62-198497
[Patent Document 7]
JP-A-8-99377
[Patent Document 8]
Japanese Patent Laid-Open No. 10-258476
[0006]
[Problems to be solved by the invention]
This invention made it the subject which should be solved to eliminate the problem of these prior arts. That is, an object of the present invention is to provide a heat-sensitive recording paper that is excellent in water resistance and has a smaller thermal curl when used as a heat-sensitive recording paper by a direct heat-sensitive recording printer and can continuously print a large number of sheets.
Another object of the present invention is to provide a thermal recording paper that is excellent in water resistance as a base material for a concealment seal, an anti-sticking label, and the like and does not require special processing to start peeling.
[0007]
[Means for Solving the Problems]
  As a result of intensive studies aimed at solving the above problems, the present inventors,It is a mixture of crystalline resin and olefinic thermoplastic elastomer30 ~ thermoplastic resin97% By weight, and inorganic fine powder and / or organic filler 70 ~3Resin film containing by weight (A)And image recording layer (B)IncludingThe thickness of the resin film (A) is 10 to 500 μmAnd the heat of crystallization is 60 J / cm³ By creating a thermal recording paper that is,The curl height after printing using a direct thermal recording printer can be reduced, and good printability can be achieved by continuous printing of many sheets.As a result, the present invention has been completed.
  That is, the present invention relates to A-4 size (210 mm × 297 mm) paper by a direct thermal recording printer.Black solidMore than 2 minutes after printingPaperThe present invention relates to a thermal recording paper having an average curl height at four corners of 50 mm or less.
  In the heat-sensitive recording paper of the present invention, the resin film (A) is further formed with a layer (C) capable of delamination of 5 to 150 g / cm width and a surface layer (D) having a breaking strength of 500 g / cm width or less. In this case, it is suitable as a heat-sensitive recording paper that does not require special processing for starting peeling.
[0008]
  In a preferred embodiment of the present invention, the resin film (A) preferably contains 35 to 97% by weight of a thermoplastic resin, 65 to 3% by weight of an inorganic fine powder and / or an organic filler.Yes.
[0009]
  The crystalline resin is an olefin resin, more preferably a propylene resin.. MaIn addition, it is preferable that the resin film (A) is stretched in at least one axial direction. It is preferable that the porosity of the resin film (A) is 75% or less. The resin film (A) preferably has a multilayer structure.
[0010]
FurtherPreferably, the resin film (A) is provided with a layer (C) capable of delamination having a peel strength of 5 to 150 g / cm width, more preferably a layer (C) capable of delamination. A surface layer (D) having a breaking strength of 500 g / cm width or less is laminated on the surface. AlsoLayer that allows delamination (C)Can be provided by a coating method. The present invention also includes a printing method including a recorded matter using a thermal recording paper and printing directly on the thermal recording paper with a thermal recording printer.
[0011]
[Form of the present invention]
The thermal recording paper containing the resin film (A) of the present invention may be a resin film (A) alone or a laminate of the resin film (A) and another thermoplastic film. ) May have a layer (C) that enables delamination, or a layer (C) and a surface layer (D) that allow delamination.
The thermal recording paper of the present invention will be described below in the order of the resin film (A), the image recording layer (B), the layer (C) capable of delamination, and the surface layer (D).
(1) Resin film (A)
The heat of crystallization of the thermal recording paper containing the resin film (A) of the present invention is 60 J / cm.^ThreeBelow, preferably 55 J / cm^ThreeOr less, more preferably 50 J / cm^ThreeIt is as follows. The heat of crystallization is 60 J / cm^ThreeIf it exceeds 1, the curl after passing directly through the thermal recording printer is large, curved, or cylindrical, making it difficult to continuously print a large number of sheets.
The average curl height capable of continuous printing of a large number of sheets is 50 mm or less, preferably 40 mm or less, more preferably 35 mm or less. If it exceeds 50 mm, it is difficult to stably stack paper at the time of printing and discharging, which causes a discharging problem.
[0012]
The heat of crystallization is measured according to JIS-K-7122, and in the present invention, the measured value at a cooling rate of 20 ° C./min (transition heat per gram (J / g)) Raw material density (g / cm^Three) Is the heat of crystallization (J / cm^Three).
The raw material density is measured in accordance with JIS-K-7112. In the present invention, the base material layer (A) or the resin film is remelted on the heater plate to remove the voids. The density of the cooled film.
Examples of the crystallization heat measuring device include a differential scanning calorimeter (DSC6200, manufactured by Seiko Instruments Inc., trade name).
The direct thermal recording printer is a recording machine that forms an image by causing a color developing reaction of a support containing a color former and a developer by the heat of a thermal head, and examples thereof include a thermal recording machine. .
[0013]
The resin film (A) of the present invention preferably has a porous structure having fine pores therein from the viewpoint of helping to reduce the weight of the thermal recording paper. The porosity is 75% or less, preferably 1 to 70%, more preferably 5 to 65%. If the porosity is 75% or less, the material strength of the film is at a good level. If the porosity is 75% or less, the material strength of the film is at a good level.
The presence of pores in the interior can be confirmed by observing the cross section with an electron microscope.
In addition, the porosity in this invention shows the area ratio (%) which a void | occupies in the area | region observed by the electron micrograph of the porosity shown by following formula (1) or a cross section. The porosity and area ratio represented by the following formula (1) are the same.
[0014]
The area ratio indicated by the pores is determined by, for example, embedding a porous thermosensitive recording paper with an epoxy resin and solidifying it, and then cutting, for example, parallel to the thickness direction of the film and perpendicular to the surface direction using a microtome. After creating a surface and metallizing the cut surface, the magnification can be easily observed with a scanning electron microscope, for example, magnified to 500 to 2000 times, or imaged by taking an electron microscope image Can also be obtained. As an example of how to determine the area ratio, the void portion was traced on the tracing film and painted, and the image was processed with an image analyzer (Nireco Corp. model: Luzex IID). ) To obtain the porosity.
[0015]
Porosity (%) = 100 × (ρ₀-Ρ) / ρ₀    ... (1)
(Where ρ₀: Density of non-porous portion of resin film (A), ρ: density of resin film (A)]
When the heat-sensitive recording paper of the present invention is a laminate having a resin film (A) on the surface, the thickness and basis weight (g / m) of the laminate and the portion from which the resin film (A) of the present invention is removed.²) To calculate the thickness and basis weight of the heat-sensitive recording paper layer of the present invention, determine the density (ρ) from this, and further determine the density (ρ₀) And the above equation (1).
[0016]
The heat shrinkage ratio after heating for 30 minutes at 120 ° C. of the resin film (A) of the present invention has an average value in both the vertical and horizontal directions of 10% or less, preferably 8% or less, more preferably 5% or less. If it exceeds 10%, the curl after passing through the thermal and thermal transfer type printer is large, curved, or cylindrical, making it difficult to continuously print a large number of sheets. This heat shrinkage ratio is determined by cutting the resin film (A) into a square of a certain size, for example, 100 mm in both length and width, measuring the dimensions in a constant temperature and humidity chamber at an air temperature of 23 ° C. and a relative humidity of 50%, and then 120 ° C. After being heat-treated in a ventilated oven for 30 minutes and taken out, it is allowed to cool in the same constant temperature and humidity chamber for 1 hour, and the dimensions are measured and calculated by comparison with that before the oven heat treatment.
[0017]
<Composition>
The compounding amount of each of the crystalline resin, amorphous resin, elastomer, inorganic fine powder and / or organic filler of the resin film (A) of the present invention is such that the heat of crystallization of the thermal recording paper containing the resin film (A). 60 J / cm^ThreeIt can be arbitrarily selected within the following range so as to be as follows.
The resin film (A) of the present invention comprises 30 to 100% by weight of thermoplastic resin, 70 to 0% by weight of inorganic fine powder and / or organic filler, preferably 35 to 97% by weight of thermoplastic resin, and inorganic fine powder. And / or 65 to 3% by weight of organic filler, more preferably 40 to 95% by weight of thermoplastic resin, and 60 to 5% by weight of inorganic fine powder and / or organic filler.
The thermoplastic resin may be composed of only a crystalline resin, an amorphous resin, or an elastomer, or may be a mixture of two or more of these. Preferably, it is a mixture of a crystalline resin and an amorphous resin or a mixture of a crystalline resin and an elastomer. More preferably, it is a mixture of a crystalline resin and an elastomer.
The kind of thermoplastic resin used for the resin film (A) of the present invention is not particularly limited.
[0018]
As for the crystalline resin, for example, ethylene resins such as high density polyethylene, low density polyethylene and linear polyethylene, olefin resins such as propylene resin; polyethylene terephthalate and copolymers thereof, polyethylene naphthalate, aliphatic polyester And thermoplastic resins such as polyester resins. These may be used in combination of two or more.
Among these, from the viewpoint of chemical resistance, low specific gravity, cost and the like, an olefin resin such as an ethylene resin or a propylene resin is preferable, and a high density polyethylene and a propylene resin are more preferable.
[0019]
Examples of the propylene-based resin include propylene homopolymers such as an isotactic polymer obtained by homopolymerizing propylene, a syndiotactic polymer, or an atactic polymer. In addition, the main component is polypropylene having various stereoregularities obtained by copolymerizing propylene with an α-olefin such as ethylene, 1-butene, 1-hexene, 1-heptene, 4-methyl-1-pentene. Copolymers can also be used. The copolymer may be a binary system or a ternary or higher multi-element system, and may be a random copolymer, a block copolymer, or a graft copolymer.
[0020]
As for amorphous resins, for example, terpene resins such as hydrogenated terpene resins and aromatic modified terpene resins; vinyl ester resins such as vinyl acetate resins and vinyl stearates; acrylic resins, methacrylic resins, methyl (Meth) acrylate resins such as (meth) acrylate resins and ethyl (meth) acrylate resins ((meth) acrylate esters refer to acrylate and methacrylate esters); polycarbonate; atactic polystyrene, syndiotactic Examples include polystyrene resins such as tick polystyrene; petroleum resins such as hydrogenated petroleum resins, aliphatic petroleum resins, aromatic petroleum resins, and cyclopentadiene petroleum resins; and thermoplastic resins such as polyphenylene sulfide. , Hydrogenated petroleum resin, aliphatic Oil resins, aromatic petroleum resins, petroleum resins such as cyclopentadiene petroleum resin. These may be used in combination of two or more.
[0021]
As for the elastomer, for example, isoprene rubber, butadiene rubber, 1,2-polybutadiene, styrene-butadiene rubber, chloroprene rubber, nitrile rubber, ethylene-propylene rubber, ethylene-propylene-ethylidene norbornene rubber, chlorosulfonated polyethylene, acrylic rubber, Examples thereof include epichlorohydrin rubber, silicone rubber, fluorine rubber, urethane rubber, and a thermoplastic elastomer having both incompatible soft segment and hard segment components in the molecule.
[0022]
Examples of thermoplastic elastomers include styrene thermoplastic elastomer (SBC), olefin thermoplastic elastomer (TPO), urethane thermoplastic elastomer (TPU), ester thermoplastic elastomer, vinyl chloride thermoplastic elastomer, and butyl rubber graft polyethylene. , Trans 1,4-polyisoprene, ionomer and the like. Among these, styrene thermoplastic elastomer (SBC) and olefin thermoplastic elastomer (TPO) are preferable, and olefin thermoplastic elastomer (TPO) is more preferable. These may be used in combination of two or more.
[0023]
The resin film (A) of the present invention preferably has a porous structure having fine pores therein by containing an inorganic fine powder and / or an organic filler. The amount of the inorganic fine powder or organic filler is 0 to 70% by weight, preferably 3 to 65% by weight, more preferably 5 to 60% by weight. In order to increase the pores, it is better that the amount of the inorganic fine powder and / or the organic filler is large. However, for the purpose of improving the surface property of the resin film (A), 70% by weight or less is preferable. good.
The kind of inorganic fine powder and / or organic filler is not particularly limited.
[0024]
Inorganic fine powders include heavy calcium carbonate, precipitated calcium carbonate, calcined clay, talc, titanium oxide, barium sulfate, aluminum sulfate, silica, zinc oxide, magnesium oxide, diatomaceous earth, silicon oxide, silica and other hydroxyl group-containing inorganic fine powders Examples thereof include composite inorganic fine powders having aluminum oxides or hydroxides around the cores, hollow glass beads and the like. Moreover, the surface treatment goods by the various surface treatment agent of the said inorganic fine powder can also be illustrated. As the surface treatment agent, for example, resin acid, fatty acid, organic acid, sulfate ester type anionic surfactant, sulfonic acid type anionic surfactant, petroleum resin acid, salts thereof such as sodium, potassium, ammonium, or These fatty acid esters, resin acid esters, waxes, paraffins and the like are preferable, and nonionic surfactants, diene polymers, titanate coupling agents, silane coupling agents, and phosphoric acid coupling agents are also preferable.
[0025]
Examples of sulfate-type anionic surfactants include long-chain alcohol sulfates, polyoxyethylene alkyl ether sulfates, sulfated oils, and their salts such as sodium and potassium, and sulfonate-type anionic surfactants. Examples of the agent include alkylbenzene sulfonic acid, alkyl naphthalene sulfonic acid, alkane sulfonic acid, paraffin sulfonic acid, α-olefinic phonic acid, alkyl sulfosuccinic acid and the like, and salts thereof such as sodium and potassium.
[0026]
Examples of fatty acids include caproic acid, caprylic acid, pelargonic acid, capric acid, undecanoic acid, lauric acid, myristic acid, palmitic acid, stearic acid, hebenic acid, oleic acid, linoleic acid, linolenic acid, and eleostearic acid. Examples of the organic acid include carboxylic acid and sulfonic acid, and examples of the nonionic surfactant include a polyethylene glycol ester type surfactant. These surface treatment agents can be used alone or in combination of two or more.
Among these, use of heavy calcium carbonate, clay, or diatomaceous earth is preferable because it is inexpensive and has good pore forming properties when formed by stretching.
[0027]
The organic filler is selected from incompatible resins having a melting point or glass transition point higher than those of the above-mentioned thermoplastic resin for the purpose of forming pores. Specific examples include polyethylene terephthalate, polybutylene terephthalate, polyamide, polycarbonate, polyethylene naphthalate, polystyrene, acrylic acid ester or methacrylic acid ester polymer or copolymer, melamine resin, polyphenylene sulfite, polyimide, poly ether ether ketone. And polyphenylene sulfide, a homopolymer of cyclic olefin, and a copolymer of cyclic olefin and ethylene [cyclic olefin copolymer (COC)]. In particular, when an olefin resin is used as the thermoplastic resin of the resin film (A), polyethylene terephthalate, polybutylene terephthalate, polyamide, polycarbonate, polyethylene naphthalate, polystyrene, a cyclic olefin homopolymer and a cyclic olefin. And a copolymer of ethylene and ethylene are preferred.
[0028]
Among inorganic fine powders or organic fillers, inorganic fine powders are more preferable from the viewpoint that the amount of heat generated during combustion is small.
The average particle size of the inorganic fine powder used in the present invention or the average dispersed particle size of the organic filler is preferably 0.01 to 30 μm, more preferably 0.1 to 20 μm, and still more preferably 0.5 to 15 μm. is there. In view of ease of mixing with the thermoplastic resin, 0.1 μm or more is preferable. In addition, when pores are generated in the interior by stretching to improve printability, the thickness is preferably 20 μm or less from the viewpoint of making it difficult to cause troubles such as sheet breakage during stretching and a decrease in strength of the surface layer.
[0029]
The average particle size of the inorganic fine powder used in the present invention is, for example, a particle measuring device, for example, a particle corresponding to 50% cumulatively measured by a laser diffraction particle measuring device “Microtrack” (trade name, manufactured by Nikkiso Co., Ltd.). It can be measured by the diameter (cumulative 50% particle diameter). In addition, the particle size of the organic filler dispersed in the thermoplastic resin by melt kneading and dispersion is obtained as an average value of the particle size by measuring at least 10 particles by electron microscope observation of the cross section of the resin film (A). Is also possible.
The fine powder used for the resin film (A) of the present invention may be selected from the above and used alone or in combination of two or more. . When two or more types are used in combination, a combination of an inorganic fine powder and an organic filler may be used.
[0030]
When these fine powders are blended and kneaded in a thermoplastic resin, an antioxidant, an ultraviolet stabilizer, a dispersant, a lubricant, a compatibilizer, a flame retardant, a color pigment, and the like can be added as necessary. Moreover, when using the resin film (A) of this invention as a durable material, it is preferable to add antioxidant, a ultraviolet stabilizer, etc. When an antioxidant is added, it is usually added within a range of 0.001 to 1% by weight. Specifically, sterically hindered phenol-based, phosphorus-based, amine-based stabilizers, and the like can be used. When using an ultraviolet stabilizer, it is usually used within the range of 0.001 to 1% by weight. Specifically, sterically hindered amines, benzotriazole-based, benzophenone-based light stabilizers, and the like can be used.
[0031]
A dispersant or a lubricant is used for the purpose of dispersing inorganic fine powder, for example. The amount used is usually in the range of 0.01 to 4% by weight. Specifically, silane coupling agents, higher fatty acids such as oleic acid and stearic acid, metal soaps, polyacrylic acid, polymethacrylic acid or salts thereof can be used. Furthermore, when using an organic filler, the type and amount of the compatibilizer are important because they determine the particle form of the organic filler. Preferred compatibilizers for organic fillers include epoxy modified polyolefins and maleic acid modified polyolefins. Moreover, it is preferable that the addition amount of a compatibilizing agent shall be 0.05-10 weight part with respect to 100 weight part of organic fillers.
[0032]
As a method for mixing the constituent components of the resin film (A) of the present invention, various known methods can be applied, and the temperature and time of mixing are appropriately selected according to the properties of the components to be used. Mixing in a state dissolved or dispersed in a solvent or a melt kneading method can be mentioned. The melt kneading method has good production efficiency. After mixing a thermoplastic resin, inorganic fine powder and / or organic filler in a powder or pellet state, and a dispersant with a Henschel mixer, ribbon blender, super mixer, etc., melt kneading with a twin-screw kneading extruder, and strand Examples include a method of extruding into a shape and cutting to form a pellet, and a method of extruding into water from a strand die and cutting with a rotary blade attached to the tip of the die. Further, there may be mentioned a method in which a dispersant in a state of being dissolved in powder, liquid or water or an organic solvent is once mixed with an inorganic fine powder and / or an organic filler and further mixed with other components such as a thermoplastic resin.
[0033]
The thickness of the resin film (A) of the present invention is not particularly limited. For example, it can be adjusted to 10 to 500 μm, preferably 30 to 300 μm.
The resin film (A) of the present invention may have a single layer structure or a two-layer structure or a multilayer structure of three or more layers. The resin film (A) of the present invention may or may not be stretched, but it can be reduced in weight by stretching holes inside the film by stretching, and has the advantage that a flexible film can be formed. And is preferably stretched at least in the uniaxial direction.
The number of stretching axes of this multilayer structure is 1 axis / 1 axis, 1 axis / 2 axis, 2 axis / 1 axis, 1 axis / 1 axis / 2 axis, 1 axis / 2 axis / 1 axis, 2 axis / 1 axis / 1 axis, 1 axis / 2 axes / 2 axes, 2 axes / 2 axes / 1 axis, 2 axes / 2 axes / 2 axes may be used. By making the resin film (A) multilayer, various functions such as writing property, printability, thermal transfer suitability, scratch resistance, and secondary processing suitability can be added.
[0034]
The heat-sensitive recording paper of the present invention may be used as a laminate by laminating the resin film (A) on at least one surface of another thermoplastic film, laminated paper, nonwoven fabric, cloth, wood board, metal plate or the like. Furthermore, as another thermoplastic film to laminate | stack, it can laminate | stack on transparent or opaque films, such as a polyester film, a polyamide film, a polystyrene film, a polyolefin film, for example.
The heat of crystallization of the heat-sensitive recording paper comprising the obtained laminate is 60 J / cm.^ThreeBelow, preferably 55 J / cm^ThreeOr less, more preferably 50 J / cm^ThreeIt is as follows.
There is no restriction | limiting in particular in the thickness of a laminated body, According to a use, it selects suitably. As an example, it is 15-2000 micrometers, Preferably it is 35-1000 micrometers, More preferably, it is 50-500 micrometers.
[0035]
<Production method>
The resin film (A) of the present invention can be produced by combining various methods known to those skilled in the art. Any thermal recording paper produced by any method is included in the scope of the present invention as long as the thermal recording paper satisfies the conditions of the present invention.
As a method for producing the resin film (A) of the present invention, various known film production techniques and combinations thereof are possible. For example, a cast molding method in which a molten resin is extruded into a sheet using a single-layer or multi-layer T-die connected to a screw-type extruder, a stretched film method using void generation by stretching, and pores during rolling Rolling method and calender molding method for generating water, a foaming method using a foaming agent, a method using pore-containing particles, an inflation molding method, a solvent extraction method, a method of dissolving and extracting mixed components, and the like. Of these, the stretched film method is preferred.
[0036]
When stretching, it is not always necessary to stretch only the resin film (A) of the present invention. For example, when it is going to finally manufacture the thermal recording paper which formed the layer (C) and surface layer (D) etc. which enable the below-mentioned delamination on the resin film (A) of this invention, The resin film (A), the layer (C) capable of delamination and the surface layer (D) may be laminated and then stretched together. If the layers are laminated in advance and stretched together, the cost becomes simpler and cheaper than the case of stretching separately and laminating. In addition, it becomes easier to control the pores formed in the layer (C) and the surface layer (D) that enable delamination from the resin film (A) of the thermal recording paper of the present invention.
[0037]
Various known methods can be used for stretching. In the case of a non-crystalline resin, the stretching temperature is not less than the glass transition temperature of the thermoplastic resin to be used, and in the case of a crystalline resin, the stretching temperature is not less than the glass transition temperature of the non-crystalline part to the melting point of the crystal part. It can be performed within a suitable temperature range. Specifically, longitudinal stretching using the peripheral speed difference of the roll group, transverse stretching using a tenter oven, rolling, inflation stretching using a mandrel for a tubular film, simultaneous biaxial stretching using a combination of a tenter oven and a linear motor It can be stretched by, for example.
[0038]
The draw ratio is not particularly limited, and is appropriately determined in consideration of the purpose of use of the thermal recording paper of the present invention and the characteristics of the thermoplastic resin used. For example, when a propylene homopolymer or a copolymer thereof is used as a thermoplastic resin, it is about 1.2 to 12 times, preferably 2 to 10 times when stretched in one direction, and biaxially stretched. The area magnification is 1.5 to 60 times, preferably 10 to 50 times. When using other thermoplastic resins, it is 1.2 to 10 times, preferably 2 to 7 times in the case of stretching in one direction, and 1.5 to 20 times in area magnification in the case of biaxial stretching. Preferably it is 4 to 12 times.
[0039]
Furthermore, heat treatment at a high temperature can be performed as necessary. The stretching temperature is a temperature 2 to 160 ° C. lower than the melting point of the thermoplastic resin to be used. When a propylene homopolymer or a copolymer thereof is used as the thermoplastic resin, it is preferably a temperature 2 to 60 ° C. lower than the melting point, The stretching speed is preferably 20 to 350 m / min.
The film thus obtained has a lot of fine pores having a porosity calculated by the above formula (1) of 75% or less, preferably 1 to 70%, more preferably 5 to 65% inside the film. It is what you have. The presence of pores makes it more supple compared to a stretched film that does not have pores.
[0040]
In order to improve the adhesion and coating properties between the resin film (A) and the image recording layer (B), it is preferable to carry out a surface treatment on at least one surface of the resin film (A).
Examples of the surface treatment method include surface oxidation treatment and treatment with a surface treatment agent. More preferably, the surface oxidation and the treatment with the surface treatment agent are combined.
Specific examples of the surface oxidation treatment include a treatment method selected from corona discharge treatment, flame treatment, plasma treatment, glow discharge treatment and ozone treatment, preferably corona treatment and flame treatment, more preferably corona treatment. It is processing.
[0041]
The treatment amount is 600 to 12,000 J / m in the case of corona treatment.²(10-200W / min / m²), Preferably 1,200 to 9,000 J / m²(20-180W ・ min / m²). 600 J / m to fully obtain the effect of corona discharge treatment²(10W / min / m²) Above, 12,000 J / m²(200W / min / m²) Since the effect of processing reaches a peak at over 1,2,000 J / m²(200W / min / m²) The following is sufficient. 8,000 to 200,000 J / m for frame processing², Preferably 20,000-100,000 J / m²Is used. 8,000 J / m for clear frame processing effect²Above, 200,000 J / m²Since the effect of the treatment will reach its peak at over 200,000 J / m²The following is sufficient.
[0042]
As the surface treatment agent, one or a mixture of two or more selected from the materials described below can be used. In particular, it is preferable to use a surface treatment agent combined with a primer as a main component because adhesion with the image recording layer (B) can be improved. Specific examples thereof include polyethyleneimines such as polyethyleneimine, butylated polyethyleneimine, hydroxypropylated polyethyleneimine, hydroxyethylated polyethyleneimine, 2,3-dihydroxypropylated polyethyleneimine, poly (ethyleneimine-urea), and polyaminepolyamide. Examples thereof include water-soluble primers selected from the group consisting of adducts, epichlorohydrin adducts such as polyamine polyamide, acrylic emulsions, and tertiary or quaternary nitrogen-containing acrylic resins.
[0043]
The method for forming the surface treatment layer using these surface treatments is not particularly limited. For example, using a roll coater, blade coater, bar coater, air knife coater, size press coater, gravure coater, reverse coater, die coater, lip coater, spray coater, etc., smoothing if necessary or extra after drying process It can be formed by removing water or a hydrophilic solvent.
When the resin film (A) is a stretched film, the coating of the surface treatment agent may be performed in one step or in multiple steps regardless of the longitudinal or lateral stretching.
[0044]
(2) Image recording layer (B)
In order to improve the reproducibility of images and characters on the printing surface side of the resin film (A) of the present invention, an image recording layer (B) which is a heat-sensitive recording layer containing an organic substance such as polyester, acrylic or polyurethane is provided. It is preferable to provide it.
The heat-sensitive recording layer contains a color former and a developer. Any combination of the color former and the developer can be used as long as they come into contact with each other to cause a color development reaction. For example, a combination of a colorless or pale white basic dye and an inorganic or organic acidic substance, or a higher fatty acid metal salt such as ferric stearate and a phenol such as gallic acid, and a diazonium salt compound and a coupler. In addition, a combination with a basic substance is applicable. The diazonium salt compound may be contained in a microcapsule whose shell is polyurea, urethane or gelatin.
[0045]
The method for forming the image recording layer (B) is not particularly limited. Examples thereof include dry lamination, extrusion lamination, wet lamination, and coating. Among these, the coating method is preferable, and the image recording layer (B) coating method is, for example, a roll coater, a blade coater, a bar coater, an air knife coater, a gravure coater, a reverse coater, a die coater, a lip coater, or a spray. Examples include a coater, a blade coater, a comma coater, a size press, and a gate roll. The coating amount of the image recording layer (B) is not particularly limited, but is usually 0.1 to 30 g / m in dry weight.²Preferably 0.2 to 10 g / m²It is a range of degree. Various known techniques in the production field of the thermal recording material, such as providing an overcoat layer for the purpose of protecting the image recording layer (B), can be added as necessary.
[0046]
(3) Layer enabling delamination (C)
The heat-sensitive recording paper of the present invention may have a layer (C) that enables delamination of the resin film (A), or a layer (C) and surface layer (D) that allow delamination.
The layer (C) capable of delamination according to the present invention is a layer whose strength is weaker than that of the resin film (A) and the surface layer (D), and the delamination of the surface layer (D) according to the present invention enables delamination. Is performed by destroying the layer (C). The preferred form of the layer (C) that enables delamination is 10 to 80% by weight of inorganic fine powder and / or organic filler, preferably 15 to 70% by weight, 90 to 20% by weight of thermoplastic resin, preferably 85 to 30%. It is a stretched thermoplastic resin film containing 10% by weight, or 10 to 80% by weight of inorganic fine powder and / or organic filler, preferably 15 to 70% by weight, 90 to 20% by weight of thermoplastic resin, preferably 85 to 30%. A binder resin containing% by weight can be provided by a coating method.
[0047]
When the content of the inorganic fine powder and / or organic filler in the layer (C) enabling delamination is less than 10% by weight, sufficient peelability cannot be obtained, and when it exceeds 80% by weight, molding stability is impaired. It is.
As a thermoplastic resin, the thermoplastic resin quoted by the term of the resin film (A) can be used, and it is preferable to use polyolefin resin similarly to the resin film (A). As the binder resin, acrylic ester resin, chlorinated polypropylene or the like is used. As the inorganic fine powder and / or organic filler, those mentioned in the section of the resin film (A) can be used.
[0048]
The thickness of the layer (C) enabling delamination is in the range of 0.1 to 500 μm, preferably in the range of 0.2 to 200 μm, and more preferably in the range of 0.5 to 100 μm. If it is less than 0.1 μm, sufficient releasability cannot be obtained, and if it is 500 μm or more, the peeled surface is not uniform and becomes uneven, which causes printing defects when printing on the peeled surface.
The layer (C) capable of delamination is preferably a stretched resin film layer, and it is possible to obtain a layer (C) capable of delamination with a small thickness and uniform uniformity by stretch molding. . Further, by stretching the layer (C) capable of delamination containing the inorganic fine powder and / or the organic filler, a fine void is formed in the layer (C) capable of delamination to reduce the strength. It becomes possible, and the below-mentioned peel strength of the surface layer (D) which is the object of the present invention can be obtained.
[0049]
(4) Surface layer (D)
The surface layer (D) in this invention is a layer provided so that it may peel from the resin film (A) by destruction of the layer (C) which enables delamination.
As a thermoplastic resin which comprises a surface layer (D), the thermoplastic resin quoted by the resin film (A) term can be used, and it is preferable to use polyolefin resin similarly to the resin film (A). Furthermore, in order to make the breaking strength of the surface layer (D) 500 g / cm or less which is the object of the present invention, the thermoplastic resin used for the surface layer (D) is desirably a resin having a low breaking strength, Specific examples include ethylene resins, propylene resins, ethylene / unsaturated carboxylic acid copolymers, and ethylene / acrylic acid copolymers.
[0050]
The surface layer (D) is a layer that may or may not contain an inorganic fine powder and / or an organic filler, and does not contain an inorganic fine powder and / or an organic filler or has a low content. The surface layer (D) excellent in transparency can be obtained, and when the resin film (A) is peeled off, the information recognizability under the surface layer (D) is excellent, which is preferable.
The surface layer (D) is preferably a stretched resin film layer, and it becomes possible to obtain a surface layer (D) that is thin by stretching and has a uniform thickness.
The film thickness of the surface layer (D) is 20 μm or less, more preferably 0.1 to 10 μm, and still more preferably 0.5 to 6 μm. When the film thickness exceeds 20 μm, it becomes difficult to obtain the surface layer (D) having the intended breaking strength of the present invention.
When the resin film (A) has a layer (C) capable of delamination, or a layer (C) and a surface layer (D) capable of delamination, the heat of crystallization of the obtained thermal recording paper is , 60J / cm^ThreeBelow, preferably 55 J / cm^ThreeOr less, more preferably 50 J / cm^ThreeIt is as follows.
[0051]
<Peel strength>
Peel strength refers to a laminated film provided with a layer (C) and a surface layer (D) capable of delamination on the resin film (A) of the present invention in a temperature-controlled room (temperature 20 ° C., relative humidity 65%). After storage for a long time, an adhesive tape (made by Nichiban Co., Ltd., trade name “Cerotape”) is attached to the surface layer (D) surface, cut into a width of 10 mm and a length of 100 mm. Using an AUTOGRAPH, the resin film (A) and the surface layer (D) are peeled off at an angle of 180 ° at a tensile speed of 300 mm / min, and the stress when the peeling is stable is measured with a load cell. This is expressed with average values in the horizontal and vertical directions. The peel strength of the present invention is 5 to 150 g / cm, preferably 7 to 100 g / cm. When the peel strength is less than 5 g / cm, there is a defect that peeling easily occurs in paper feeding and discharging at the time of secondary processing such as printing, printing, and cutting, and there is a problem in secondary workability. If the width exceeds 150 g / cm, the surface layer (D) does not peel or it is necessary to increase the stress required for peeling, which is not practical. In addition, material destruction occurs in places other than the layer (C) that enables delamination, and fluffing occurs on the peeled surface.
[0052]
<Break strength>
After storing the laminated film provided with the layer (C) and the surface layer (D) enabling delamination on the resin film (A) of the present invention in a thermostatic chamber (temperature 20 ° C., relative humidity 65%) for 12 hours, Cut to a width of 10 mm and a length of 100 mm, and further reinforced with an adhesive tape (made by Nichiban Co., Ltd., trade name “cello tape”) up to half the longitudinal direction of the surface layer (C) surface. The surface layer (D) of the portion reinforced with the adhesive tape is peeled off from the resin film (A) by hand to prepare a sample for measuring the breaking strength. The part of the prepared sample where the surface layer (D) is not peeled off and the peeled surface layer (D) are set in a tensile tester (manufactured by Shimadzu Corporation, AUTOGRAPH), and the surface layer ( D) reads the load at the time of breaking, and expresses it as an average value in the horizontal and vertical directions.
The breaking strength of the surface layer (D) of the present invention is 500 g / cm or less, preferably 400 g / cm or less, more preferably 300 g / cm or less. When the breaking strength of the surface layer (D) is higher than 500 g / cm, in order to peel off the surface layer (D) from the resin film (A), special processing such as notches and slits is applied only to the surface layer (F). And the desired performance of the present invention is not exhibited.
[0053]
<Curl after printing direct thermal recording printer>
When the thermal recording paper of the present invention is cut to A-4 size (210 mm × 297 mm) and directly printed by a thermal recording printer, the average curl height at the four corners after 2 minutes or more from printing is 50 mm or less. It is preferable.
More specifically, the thermal recording paper is cut into A-4 size (210 mm × 297 mm), left in a constant temperature and humidity room at a temperature of 23 ° C. and a relative humidity of 50% for one day, and then a commercially available direct thermal recording printer “MULTISCAN VIDEO PRINTER”. UP-930 "(manufactured by Sony, product name) is used for printing through a paper passage route with the image recording layer (B) as the printing surface.
A black solid is selected for the print test model diagram. After passing through the printer, leave the thermal recording paper on a flat surface at a humidity of 23 ° C and a relative humidity of 50%, and place the curls at the four corners upward after 2 minutes. The average value of the heights of the four corners is measured with the positive value when lifted to the side and the negative value when lifted to the opposite side of the printing surface. The average value is preferably 50 mm or less. If it exceeds 50 mm, it is difficult to continuously print a large number of sheets.
[0054]
<Printing>
The thermal recording paper of the present invention is used as a thermal recording paper for direct thermal recording printers such as thermal facsimiles, video printers, barcode printers, etc., as well as product names, manufacturers, expiration dates, character drawings, entry fields, etc. It is possible to produce a recorded matter printed and printed by letterpress printing, gravure printing, flexographic printing, solvent-type offset printing, UV-curing offset printing, and roll-type printing in the form of a sheet.
In addition, after providing a coating layer such as an ink jet receiving layer or a toner receiving layer on the front surface and back surface of the resin film (A) and / or the layer (C) or the surface layer (D) capable of delamination as required. Also, a recorded matter printed and printed by ink jet recording can be created.
[0055]
【Example】
Hereinafter, the present invention will be described more specifically with reference to Examples, Comparative Examples and Test Examples. The materials, amounts used, ratios, operations, and the like shown in the following examples and the like can be appropriately changed without departing from the gist of the present invention. Therefore, the scope of the present invention is not limited by the following examples.
The thermal recording paper of the present invention and the comparative thermal recording paper were produced according to the following procedure. Table 1 summarizes the thermoplastic resin, inorganic fine powder, and organic filler used.
[0056]
[Table 1]

[0057]
  (referenceExample 1)
  <Resin film (A)>
  A composition [○ 1] in which 20% by weight of charcoal cal (described in Table 1) is blended with a mixture of 30% by weight of PP (described in Table 1) and 50% by weight of HSBR (described in Table 1) at 250 ° C. Were kneaded with an extruder set to, extruded into a strand, and cut into pellets. This composition [◯ 1] was extruded into a film form from a T die connected to an extruder set at 250 ° C., and cooled with a cooling device to obtain an unstretched film (thickness: 100 μm, heat of crystallization: 29J). / Cm^Three).
[0058]
The applied energy density is 100 W · min / m on both sides of this film.²The corona discharge treatment was performed at
In addition, in the melt-kneading of the resin component or the mixture of the fine powder and the resin component in each Example and Comparative Example, the total weight of the resin component and the fine powder is 100 parts by weight, and in addition to this, BHT is used as an antioxidant. 0.2 parts by weight of (4-methyl-2,6-di-t-butylphenol) and 0.1 parts by weight of Irganox 1010 (phenolic antioxidant, manufactured by Ciba Geigy Corporation) were added.
The particle diameter of the calcium carbonate powder used in the examples of the present specification is a cumulative 50% particle diameter measured by a laser diffraction particle measuring device “Microtrack” (trade name, manufactured by Nikkiso Co., Ltd.).
[0059]
<Formation of image recording layer (B)>
A direct heat-sensitive recording layer forming composition comprising the following components was applied to the resin film (A) to form an image recording layer (B) having a thickness of 10 μm when dried.

The composition having this ratio is pulverized with a sand grinder to an average particle size of 2 μm.
[0060]

The composition having this ratio is pulverized with a sand grinder to an average particle size of 2 μm.
25 parts by weight of liquid A, 180 parts by weight of liquid B, 70 parts by weight of talc 50% aqueous dispersion, and 240 parts by weight of a 5% aqueous solution of hydroxyethyl cellulose as a binder were mixed.
This was evaluated in the following manner. The evaluation results are summarized in Table 2.
[0061]
<Evaluation>
i. Evaluation of curl height
The obtained heat-sensitive recording paper of the present invention was cut into A-4 size (210 mm × 297 mm) and left in a constant temperature and humidity room at a temperature of 23 ° C. and a relative humidity of 50% for 1 day. Next, black solid printing was performed with a commercially available direct thermal recording printer “MULTISCAN VIDEO PRINTER UP-930” (product name, manufactured by SONY) through a paper passing path with the image recording layer (B) as a printing surface.
After passing through the printer, the thermal recording paper was left on a flat table in an atmosphere of a humidity of 23 ° C. and a relative humidity of 50%, and the curl height at the four corners after 2 minutes of the paper passing was evaluated.
[0062]
ii. Evaluation of print quality
The print density of the black solid portion after printing was visually observed and evaluated according to the following criteria.
Very good (◎) No density unevenness. (Actual use possible)
Good (◯) There is a little density unevenness. (Actual use possible)
There is defective (x) density unevenness. (Difficult to use)
iii. Evaluation of water resistance
The obtained thermal recording paper was cut into a 50 mm × 50 mm square, immersed in water at 20 ° C. for 1 day, and then the state when the film was torn by hand was evaluated according to the following criteria.
Very good (◎) The substrate is not broken. (Actual use possible)
Good (◯) base material is not easily broken. (Actual use possible)
A defective (x) substrate is easily broken. (Difficult to use)
[0063]
  (referenceExample 2)
  Except that the types and amounts of the composition components of the composition [○ 2] are those described in Table 2,referenceA thermal recording paper was prepared and evaluated in the same manner as in Example 1. The evaluation results are shown in Table 2.
  (referenceExample 3)
  The types and amounts of the ingredients of the composition [○ 3] are those listed in Table 2,referenceAfter obtaining an unstretched film by the same operation as in Example 1, the unstretched film was heated to 145 ° C. (temperature a) and then stretched 5 times in the longitudinal direction to obtain a stretched film (thickness: 100 μm, Heat of crystallization: 37 J / cm^Three). afterwards,referenceA thermal recording paper was prepared and evaluated in the same manner as in Example 1. The evaluation results are shown in Table 2.
[0064]
  (Example 4)
  The types and amounts of the ingredients of the composition [◯ 4] are as shown in Table 2,referenceAfter obtaining an unstretched film by the same operation as in Example 1, the unstretched film was heated to 140 ° C. (temperature a) and then stretched 5 times in the longitudinal direction to obtain a stretched film.
  The composition [◯ 4] was extruded into a film form from a T-die connected to an extruder set at 240 ° C. The obtained film was laminated on both sides of the 5-fold stretched film prepared by the above operation, cooled to 55 ° C., heated to 160 ° C. (temperature b), and stretched 8 times in the transverse direction with a tenter. Then, it annealed at 165 degreeC (temperature c), cooled to 50 degreeC, slit the ear | edge part, and obtained the film of 3 layer structure (uniaxial stretching / biaxial stretching / uniaxial stretching) (thickness) : 15/70/15 μm = 100 μm, heat of crystallization: 41 J / cm^Three). afterwards,referenceA thermal recording paper was prepared and evaluated in the same manner as in Example 1. The evaluation results are shown in Table 2.
[0065]
  (Example 5)
  The type and amount of the composition component of composition [○ 5] are as shown in Table 2, and a multi-layer die connected to two different extruders set at 250 ° C. is used to form a three-layer structure. The film was extruded in the form of a film and then cooled with a cooling device to obtain an unstretched film.
  Next, this unstretched film was heated to 140 ° C. (temperature a), then stretched 5 times in the longitudinal direction, and then cooled to obtain a stretched film.
  Again, it was heated to 163 ° C. (temperature b) and stretched 8 times in the transverse direction with a tenter. Then, it annealed at 168 degreeC (temperature c), cooled to 50 degreeC, slit the ear | edge part, and obtained the film of 3 layer structure (biaxial stretching / biaxial stretching / biaxial stretching) (thickness) : 15/70/15 μm = 100 μm, heat of crystallization: 41 J / cm^Three). afterwards,referenceA thermal recording paper was prepared and evaluated in the same manner as in Example 1. The evaluation results are shown in Table 2.
[0066]
  (Comparative Example 1)
  Except that the types and amounts of the composition components of the composition [○ 6] are those shown in Table 2,referenceA thermal recording paper was prepared and evaluated in the same manner as in Example 1. The evaluation results are shown in Table 2.
  (Comparative Example 2)
  A thermal recording paper was prepared and evaluated in the same manner as in Example 5 except that the types and amounts of the components of the composition [◯ 7] were those shown in Table 2. The evaluation results are shown in Table 2.
  (Comparative Example 3)
  Using commercially available pulp paper “My Recycle Paper 100w” (NBS Ricoh Co., Ltd., trade name)referenceAn image recording layer formed by the same operation as in Example 1 was prepared and evaluated. The evaluation results are shown in Table 2.
[0067]
[Table 2]

[0068]
  (referenceExample 6)
  The types and amounts of the components of the composition [○ 8] are those shown in Table 3, and the composition [○ 8] as the layer (C) that enables delamination and the composition as the resin film (A) [ ○ 3] is extruded in the form of a film using a multilayer die to which two different extruders set at 250 ° C. are connected so as to form a two-layer structure, and this is cooled. To obtain an unstretched film.
  Next, this unstretched film was heated to 150 ° C. (temperature a), then stretched 5 times in the longitudinal direction and then cooled to obtain a stretched film.
  Again, it was heated to 143 ° C. (temperature b) and stretched 8 times in the transverse direction with a tenter. Then, it annealed at 160 degreeC (temperature c), cooled to 50 degreeC, slit the ear | edge part, and obtained the film of the 2 layer ((C) / (A): wall thickness 15/80 micrometer) structure. (Thickness: 95 μm). afterwards,referenceA thermal recording paper was obtained by the same operation as in Example 1.
[0069]
《Adhesive coating》
The pressure sensitive adhesive “Olivein BPS-1109” (trade name, manufactured by Toyo Ink Chemical Co., Ltd.) on the layer (C) surface enabling delamination of the obtained thermal recording paper was 25 g / m in solid content.²Then, it was coated with a comma coater and dried.
This was evaluated in the following manner. The evaluation results are summarized in Table 3.
[0070]
<Evaluation>
iv. Peel initiation
The peel strength of the layer (C) enabling delamination and the breaking strength of the surface layer (D) were measured by the methods described in <Peel strength> and <Rupture strength>, respectively.
Cut the adhesive coated thermal recording paper into a 5cm x 5cm square and stick it on a government-made postcard. Then, hold one of the four sides of the thermal recording paper by hand and peel it off from the government-made postcard. The state until the peeling of the layer (C) or the surface layer (D) that enables the film was evaluated according to the following criteria.
Very good (◎) peeling starts immediately. (Actual use possible)
It takes 2 mm or more before good (◯) peeling starts. (Actual use possible)
Slightly poor (Δ) peeling starts partially. (Difficult to use)
It takes 10 mm or more before defective (x) peeling starts. (Difficult to use)
[0071]
v. Delamination propagation
After the adhesive-coated thermal recording paper is cut into a 5cm x 5cm square and pasted on a government-made postcard, adhesive tape (made by Nichiban Co., Ltd., product) Name "cello tape") is attached, the layer (C) or the surface layer (D) that enables delamination can be easily peeled off, and the resin film (A) can be peeled off from a government-made postcard to allow delamination The propagation state and peeling force of the layer (C) or the surface layer (D) are visually observed and evaluated according to the following criteria.
Very good (◎) Peeling force is light and the whole surface is transmitted cleanly. (Actual use possible)
Good (○) Peeling force is slightly heavy, but propagates cleanly on the entire surface. (Actual use possible)
Slightly poor (△) peeling force is very heavy, but it propagates cleanly on the whole surface. (Difficult to use)
Defective (x) cannot be propagated all over and is cut off halfway. (Difficult to use)
[0072]
vi. Information hiding
Print 26 letters of alphabet with a letter size of 10 points on a government-made postcard, stick the adhesive-coated thermal recording paper on the printed face of the alphabet, and visually observe the concealment of the letters seen through the produced film. The evaluation was based on the following criteria.
Very good (◎) Actual use possible.
Good (○) can be used.
Somewhat bad (△) difficult to use.
Defective (×) difficult to use.
[0073]
vii. Information recognition
For barcode reading, barcode (CODE39) is printed on the synthetic paper “VES85” (trade name, manufactured by Yupo Corporation) with barcode printer “B30” (trade name, manufactured by Tech Co., Ltd.). A sample was created.
Adhesive-coated thermal recording paper is pasted on the barcode printing surface of synthetic paper, 10 samples are created with the barcode hidden, and the barcode after the resin film (A) is peeled off is displayed on the barcode reader “ The number of times of successful barcode recognition was evaluated according to the following criteria using “LASERCHEK II” (trade name, manufactured by Fuji Electric Refrigerator Co., Ltd.).
Very good (◎) Successful 10 times. (Actual use possible)
Good (◯) 8-9 successes. (Actual use possible)
Slightly bad (△) 2-7 successes. (Difficult to use)
Defect (x) Success count is 1 or less. (Difficult to use)
[0074]
  (referenceExample 7)
  LDPE (described in Table 1) was extruded into a film form from a T-die connected to an extruder set at 180 ° C. The obtained film was laminated on the layer (C) surface allowing delamination of the 5-fold stretched film prepared by the same operation as in Example 6, and a surface layer (D) was provided, and after cooling to 55 ° C, It heated to 148 degreeC (temperature b), and extended | stretched 8 times in the horizontal direction with the tenter. Then, it anneals at 162 degreeC (temperature c), it cools to 50 degreeC, slits an ear | edge part, and is 3 layers ((D) / (C) / (A): thickness 5/15/80 micrometer) A film having a structure was obtained (thickness: 100 μm).referenceA thermal recording paper was prepared by the same operation as in Example 6 and evaluated. The evaluation results are shown in Table 3.
[0075]
(Comparative Example 4)
Composition [(6)] (described in Table 2) on the resin film (A), composition [(9)] (described in Table 3) on the layer (C) enabling delamination, and surface layer (D) EVA (described in Table 1) was used, and a thermal recording paper was prepared and evaluated in the same manner as in Example 7 except for the molding conditions described in Table 3. The evaluation results are shown in Table 3.
[0076]
[Table 3]

[0077]
【The invention's effect】
The thermal recording paper of the present invention reduces curling after direct thermal printer printing, achieves good printability by continuous printing of a large number of sheets, and the recorded paper is excellent in water resistance and mechanical properties, so it can be used indoors and outdoors. Useful for industrial use. In addition, it does not require special processing to start peeling, and the surface layer peels off with a small force, so it can be used in a wide range of applications such as delivery tables, concealment seals, anti-stick labels, tamper-proof seals, application seals, coupons, etc. It can also be used effectively.

Claims (6)

Resin film (A) and image recording layer (B ) containing 30 to 97 % by weight of thermoplastic resin, which is a mixture of crystalline resin and olefinic thermoplastic elastomer, and 70 to 3 % by weight of inorganic fine powder and / or organic filler ) the a including the heat-sensitive recording paper, a thickness of the resin film (a) is 10 to 500 [mu] m, the heat of crystallization of the resin film (a) is at 60 J / cm ³ or less, and the thermosensitive recording The thermal recording paper, wherein the paper is cut into A-4 size (210 mm × 297 mm) paper, and the average of curl heights at the four corners at 2 minutes or more after direct black printing by a direct thermal recording printer is 50 mm or less. . 2. The thermal recording paper according to claim 1, wherein the crystalline resin is an olefin resin. The heat-sensitive recording paper according to claim 1 or 2 , wherein the heat-sensitive recording paper is provided with an image recording layer (B) after at least one side of the resin film (A) is subjected to an oxidation treatment . The heat-sensitive film according to any one of claims 1 to 3, wherein the resin film (A) includes a layer (C) capable of delamination having a peel strength of 5 to 150 g / cm width. Recording sheet. A resin film (A) is, according to claim 4, breaking strength on the surface of the layer (C) which allows delamination is characterized in that, including the surface layer is 500 g / cm width or less (D) Thermal recording paper. Printing method characterized by printing directly on the heat-sensitive recording printers on the thermosensitive recording sheet of any one of claims 1-5.