JPH10101128A5

JPH10101128A5 -

Info

Publication number: JPH10101128A5
Application number: JP1996273958A
Authority: JP
Filing date: 1996-09-26
Publication date: 2004-09-30
Anticipated expiration: 2016-09-26

Description

【０００４】
【課題を解決するための手段】
本発明は、結晶性ポリオレフィン（Ａ₁ ）７０〜９９重量％と無機微細粉末（Ａ₂ ）３０〜１重量％とを配合した樹脂組成物を基材とする芯材層（Ａ）の少なくとも片面に、無機微細粉末（Ｂ₂ ）３５〜６０重量％および結晶性ポリオレフィン（Ｂ₁ ）６５〜４０重量％とを含有する樹脂組成物よりなる表面層（Ｂ）が積層された多層フイルムを、結晶性ポリオレフィン（Ａ₁ 、Ｂ₁ ）の融点より低い温度で一軸方向に３〜１０倍延伸して、各層に独立した微細なボイドを多数形成させて得た不透明度（ＪＩＳＰ−８１３８）が７０％以上であり、延伸方向のエンメンドルフ引裂強度（ＪＩＳＫ−７１２８）が５〜１５ｇである一軸延伸多層フィルムの表面層（Ｂ）の表面に製造元、品名、バーコード等を印刷し、この印刷面とは反対側の一軸延伸多層フィルムの裏面に感圧性粘着剤層（５）を設けた構造の結束紐を提供するものである。[0004]
[Means for solving the problem]
The present invention provides a multilayer film comprising a core layer (A) based on a resin composition containing 70 to 99% by weight of crystalline polyolefin ( _A1 ) and 30 to 1% by weight of inorganic fine powder ( _A2 ), and a surface layer (B) made of a resin composition containing 35 to 60% by weight of inorganic fine powder ( _B2 ) and 65 to 40% by weight of crystalline polyolefin ( _B1 ) laminated on at least one side of the core layer (A), the surface layer (B) being made of a resin composition containing 35 to 60% by weight of inorganic fine powder (B2) and 65 to 40% by weight of crystalline polyolefin (B1). The multilayer film is stretched 3 to 10 times in an uniaxial direction at a temperature lower than the melting points of the crystalline polyolefins ( _A1 , _B1 ) to form a large number of independent fine voids in each layer, and has an opacity (JIS P-8138) of 70% or more, and an Emmendorf tear strength (JIS P-8138) in the stretching direction. The present invention provides a binding cord having a structure in which the manufacturer, product name, bar code, etc. are printed on the surface of the surface layer (B) of a uniaxially oriented multilayer film having a molecular weight of 5 to 15 g (K-7128), and a pressure-sensitive adhesive layer (5) is provided on the back surface of the uniaxially oriented multilayer film opposite to the printed surface.

【０００５】
【作用】
一軸延伸多層フィルムの延伸方向に沿ってノッチが設けられているので、結束紐１、１に力がかけられると、ノッチに集中した応力が多層フィルムの延伸配向方向に集中してかかるので、従来の合成紙を基材とした結束紐よりもより小さい力で直線方向に一定幅で各結束紐を切り裂くことができる。
従来の合成紙を素材とする結束紐においては、基材層が二軸延伸フィルムであるため、表裏層の一軸延伸フィルムの延伸方向（横方向）に設けられたノッチにかかる応力は基材層の二軸延伸フィルムの縦方向の延伸配向の抗張力の抵抗を受けるので引裂強度が本発明の結束紐よりも大きくなるし、又、結束紐の引裂にかける応力が高すぎる場合には、表裏層又は裏面層が基材層より剥がれることもある。[0005]
[Effect]
Since notches are provided along the stretching direction of the uniaxially stretched multilayer film, when force is applied to the binding strings 1, 1, the stress concentrated at the notches is concentrated in the stretching orientation direction of the multilayer film, so that each binding string can be torn in a linear direction at a constant width with less force than with conventional binding strings based on synthetic paper.
In conventional binding ties made from synthetic paper, the base layer is a biaxially oriented film, so the stress applied to the notches in the stretching direction (horizontal direction) of the uniaxially oriented film of the front and back layers is resisted by the tensile strength of the longitudinal stretch orientation of the biaxially oriented film of the base layer, resulting in a greater tear strength than that of the binding ties of the present invention.Furthermore, if the stress applied to tear the binding tie is too high, the front and back layers or the back layer may peel off from the base layer.

【０００６】
【発明の具体的説明】
（Ｉ）一軸延伸多層フイルム
本発明の一軸延伸多層フイルムは、結晶性ポリオレフィン７０〜９９重量％と無機微細粉末３０〜１重量％とを配合した樹脂組成物を基材とする芯材層（Ａ）の少なくとも片面に、無機微細粉末を３５〜６０重量％および結晶性ポリオレフィン６５〜４０重量％を含有する樹脂組成物よりなる表面層（Ｂ）が積層された多層フイルムを、結晶性ポリオレフィンの融点より低い温度で一軸方向に３〜１０倍延伸して、各層に独立した微細なボイドを多数形成させて得た、延伸方向の引裂強度が５〜１５ｇの、一軸延伸多層フイルムである。[0006]
[Specific Description of the Invention]
(I) Uniaxially Stretched Multilayer Film The uniaxially stretched multilayer film of the present invention is a uniaxially stretched multilayer film having a tear strength of 5 to 15 g in the stretching direction. The multilayer film comprises a core layer (A) based on a resin composition containing 70 to 99% by weight of a crystalline polyolefin and 30 to 1% by weight of an inorganic fine powder, and a surface layer (B) composed of a resin composition containing 35 to 60% by weight of an inorganic fine powder and 65 to 40% by weight of a crystalline polyolefin laminated on at least one side of the core layer. The surface layer (B) is made of a resin composition containing 35 to 60% by weight of an inorganic fine powder and 65 to 40% by weight of a crystalline polyolefin. The multilayer film is then stretched 3 to 10 times in the uniaxial direction at a temperature lower than the melting point of the crystalline polyolefin to form numerous independent microvoids in each layer.

【００１０】
（ロ）表面層（Ｂ）：
表面層の無機微細粉末（Ｂ₂ ）としては、芯材層（Ａ）で挙げた無機微細粉末を使用することができる。表面層と芯材層の無機微細粉末は同種のものであっても、異種のものであってもよい。
表面層の結晶性ポリオレフィン（Ｂ₁ ）としては芯材層（Ａ）に用いられる結晶性ポリオレフィンと同種のものが用いられ、コストの面からプロピレン単独重合体、プロピレン・エチレンランダム共重合体、密度が０．９５０〜０．９７０ｇ／ｃｍ³ の高密度ポリエチレンが好ましい。
表面層（Ｂ）における無機微細粉末の含有率が３５重量％未満では、結束紐の引裂力が大きくなる。逆に６０重量％を越えては、ロール延伸性が悪くなる。
一軸延伸多層フイルムは、例えば以下に示す如きの方法により製造することができる。[0010]
(ii) Surface layer (B):
The inorganic fine powder ( _B2 ) for the surface layer can be the same as the inorganic fine powder for the core layer (A). The inorganic fine powders for the surface layer and the core layer may be the same or different.
The crystalline polyolefin (B ₁ ) for the surface layer is the same as the crystalline polyolefin used for the core layer (A), and from the standpoint of cost, propylene homopolymer, propylene-ethylene random copolymer, or high-density polyethylene with a density of 0.950 to 0.970 g/cm ³ is preferred.
If the content of the inorganic fine powder in the surface layer (B) is less than 35% by weight, the tear strength of the binding cord increases, whereas if it exceeds 60% by weight, the roll stretchability deteriorates.
The uniaxially stretched multi-layer film can be produced, for example, by the following method.

【００１３】
この一軸延伸多層フイルムの肉厚は、芯材層（Ａ）の肉厚が２０〜１５０μｍ、好ましくは３０〜１２０μｍで、表面層（Ｂ）の肉厚が１〜３０μｍ、好ましくは５〜３０μｍであり、全肉厚は、３０〜２００μｍ、好ましくはコスト面から５０〜１２０μｍの範囲である。
又、この一軸延伸多層フイルムは不透明度（ＪＩＳＰ−８１３８）が７０％以上、好ましくは８０〜１００％であり、延伸方向のエンメンドルフ引裂強度が５〜１５ｇ、延伸方向の引張弾性率（ＪＩＳＰ−７１２７）が１８，０００〜４０，０００ｋｇｆ／ｃｍ² ，好ましくは２０，０００〜３５，０００ｋｇｆ／ｃｍ² の範囲のものである。[0013]
The thickness of this uniaxially stretched multilayer film is 20 to 150 μm, preferably 30 to 120 μm, for the core layer (A), 1 to 30 μm, preferably 5 to 30 μm, for the surface layer (B), and 30 to 200 μm, preferably 50 to 120 μm, for a total thickness of 30 to 200 μm, preferably 50 to 120 μm from the viewpoint of cost.
The uniaxially stretched multilayer film has an opacity (JIS P-8138 ) of 70% or more, preferably 80 to 100%, an Emmendorf tear strength in the stretching direction of 5 to 15 g, and a tensile modulus in the stretching direction (JIS P-7127) of 18,000 to 40,000 kgf/ ^cm² , preferably 20,000 to 35,000 kgf/ ^cm² .

【００１４】
〔印刷層〕
前記一軸延伸多層フィルムの表面層（Ｂ）の上に製造元、商品名、バーコード等が印刷される。
（ＩＩ）結束紐群
結束紐群は図１に示すように一軸延伸多層フィルムの延伸方向（機械方向；縦方向）に応力が集中するようノッチが設けられる。
各片を指でもって逆方向に引き裂くことにより個片の結束紐が得られる。[0014]
[Printing layer]
The manufacturer, trade name, bar code, etc. are printed on the surface layer (B) of the uniaxially stretched multilayer film.
(II) Binding cord group As shown in Figure 1, the binding cord group has notches so that stress is concentrated in the stretching direction (machine direction; longitudinal direction) of the uniaxially stretched multilayer film.
Each piece is torn in opposite directions with the fingers to obtain individual ties.

【００１５】
〔感圧性粘着剤〕
感圧粘着剤としては、公知の感圧粘着剤を使用することができる。具体的には、カゼイン、ポリビニルアルコール、各種加工澱粉、ポリアクリルアミド、カルボキシメチルセルロース、メチルセルロースや、カルボキシ変性スチレン・ブタジエンラテックス、アクリロニトリル・ブタジエンラテックス、メチルメタクリル・ブタジエンラテックス等のゴム系粘着剤、アクリル酸エステル系樹脂エマルジョン等のアクリル系粘着剤、シリコーン系粘着剤、ビニール系粘着剤等を挙げることができる。これらの粘着剤の中でも、ゴム系粘着剤を用いることが好ましい。
該粘着剤は、固形分量で２５〜１５０ｇ／ｍ²、好ましくは５０〜１２０ｇ／ｍ²で塗布されて、肉厚が２０〜１４０μｍ、好ましくは４５〜１１０μｍに形成される。
また、該粘着剤は、予め剥離紙の表面に形成しておき、一軸延伸多層フィルムと貼合してもよい。[0015]
[Pressure-sensitive adhesive]
Known pressure-sensitive adhesives can be used as the pressure-sensitive adhesive. Specific examples include casein, polyvinyl alcohol, various modified starches, polyacrylamide, carboxymethyl cellulose, methyl cellulose, rubber-based adhesives such as carboxy-modified styrene-butadiene latex, acrylonitrile-butadiene latex, and methyl methacrylate-butadiene latex, acrylic-based adhesives such as acrylic ester resin emulsions, silicone-based adhesives, and vinyl-based adhesives. Among these adhesives, rubber-based adhesives are preferred.
The adhesive is applied in a solid content of 25 to 150 g/m ² , preferably 50 to 120 g/m ² , to form a thickness of 20 to 140 μm, preferably 45 to 110 μm.
The adhesive may also be formed in advance on the surface of a release paper, which is then laminated to the uniaxially stretched multilayer film.

【００１７】
【実施例】
本発明の一軸延伸多層フイルムを用いた結束紐について、以下にその実施例及び比較例を挙げて更に具体的に説明する。
〔１〕評価方法
実施例及び比較例における物性の評価は以下に示す方法によって行なった。
引張弾性率
ＪＩＳＫ−７１２７による（測定温度２３℃）。
不透明度
ＪＩＳＰ−８１３８による。
密度
ＪＩＳＰ−８１１８による。
白色度
ＪＩＳＬ−１０１５による。[0017]
[Example]
The binding cord using the uniaxially stretched multilayer film of the present invention will be described in more detail below with reference to examples and comparative examples.
[1] Evaluation Methods Evaluation of physical properties in the examples and comparative examples was carried out by the following methods.
Tensile modulus: According to JIS K-7127 (measurement temperature: 23°C).
Opacity: According to JIS P-8138 .
Density: According to JIS P-8118.
Whiteness: According to JIS L-1015.

【００２０】
〔２〕実施例
（実施例１）
一軸延伸多層フィルムよりなる結束紐の製造
(1) メルトフローレート（ＭＦＲ）１ｇ／１０分、結晶化度６７％、融点１６７℃のプロピレン単独重合体６０重量部、融点１３４℃の高密度ポリエチレンを２０重量部および平均粒径１．５μｍの炭酸カルシウム２０重量部を配合した組成物を２５０℃に設定された押出機にて溶融混練し、芯材層（Ａ）用として共押出ダイに供給した。
(2) また、別の２５０℃に設定された押出機にはＭＦＲ１０ｇ／１０分、結晶化度６４％、融点１６７℃のプロピレン単独重合体６０重量部に、平均粒径１．５μｍの炭酸カルシウム３７重量部、酸化チタン３重量部を配合した組成物（Ｂ）を２４０℃で溶融混練し、共押出ダイに供給し同ダイ内で前記芯材層（Ａ）用組成物の両面に積層される様にしてシート状に押し出し、これを冷却ロールにて６０℃迄冷却して３層構造（Ｂ／Ａ／Ｂ）の無延伸シートを得た。[0020]
[2] Example (Example 1)
Manufacturing of binding strings made of uniaxially stretched multilayer films
(1) A composition containing 60 parts by weight of a propylene homopolymer having a melt flow rate (MFR) of 1 g/10 min, a crystallinity of 67%, and a melting point of 167°C, 20 parts by weight of a high-density polyethylene having a melting point of 134°C, and 20 parts by weight of calcium carbonate having an average particle size of 1.5 μm was melt-kneaded in an extruder set at 250°C, and supplied to a co-extrusion die for use as the core layer (A).
(2) In addition, in another extruder set at 250°C, composition (B) containing 60 parts by weight of propylene homopolymer having an MFR of 10 g/10 min, a crystallinity of 64%, and a melting point of 167°C, 37 parts by weight of calcium carbonate having an average particle size of 1.5 μm, and 3 parts by weight of titanium oxide was melt-kneaded at 240°C, supplied to a co-extrusion die, and extruded into sheets so as to be laminated on both sides of the composition for core layer (A) within the die. This was then cooled to 60°C with a cooling roll to obtain an unstretched sheet with a three-layer structure (B/A/B).

【００２３】
（比較例１）
実施例１において、合成紙として王子油化合成紙（株）製の一軸延伸／二軸延伸／一軸延伸の積層構造フィルムの合成紙「ユポＦＰＧ８０（肉厚８０μｍ；商品名）」を用いる他は同様にして結束紐用シートを製造した。その物性は表１に示す値であった。
（比較例２）
市販の結束紐〔無延伸ポリプロピレンフィルム（ＣＰＰ）の表面に白ベタ印刷をし、更にグラビア藍印刷で商品名、製造元、バーコードを印刷し、裏面に感圧粘着剤がグラビアロールを用いて塗布されたもの〕の物性を表１に示す。
（実施例２、実施例３）
実施例１において、延伸倍率、炭酸カルシウムの配合量を表１のようにした他は同様にして結束紐を得た。[0023]
(Comparative Example 1)
A sheet for binding cords was produced in the same manner as in Example 1, except that the synthetic paper used was "Yupo FPG80 (thickness 80 μm; product name)," a uniaxially oriented/biaxially oriented/uniaxially oriented laminated film synthetic paper manufactured by Oji Yuka Synthetic Paper Co., Ltd. The physical properties were as shown in Table 1.
(Comparative Example 2)
The physical properties of a commercially available binding cord (made of unstretched polypropylene film (CPP) with a solid white print on the front, the product name, manufacturer, and barcode printed in indigo gravure, and a pressure-sensitive adhesive applied to the back using a gravure roll) are shown in Table 1.
(Examples 2 and 3)
A binding cord was obtained in the same manner as in Example 1, except that the draw ratio and the amount of calcium carbonate blended were as shown in Table 1.

【００２４】
（実施例４）
実施例１において、一軸延伸三層フィルムの代わりに、次の製法で得られた一軸延伸二層フイルムを用いる他は同様にして結束紐を得た。
一軸延伸二層フィルムの製造
(1) メルトフローレート（ＭＦＲ）０．８ｇ／１０分、結晶化度６７％、融点１６７℃のプロピレン単独重合体７５重量部、融点１３４℃の高密度ポリエチレン５重量部および、平均粒径１．５μｍの炭酸カルシウム２０重量部を配合した組成物（Ａ）を、２５０℃に設定された押出機にて溶融混練し、芯材層（Ａ）用として共押出ダイに供給した。[0024]
Example 4
A binding cord was obtained in the same manner as in Example 1, except that a uniaxially stretched two-layer film obtained by the following method was used instead of the uniaxially stretched three-layer film.
Manufacturing of uniaxially stretched two-layer film
(1) Composition (A) containing 75 parts by weight of a propylene homopolymer having a melt flow rate (MFR) of 0.8 g/10 min, a crystallinity of 67%, and a melting point of 167°C, 5 parts by weight of a high-density polyethylene having a melting point of 134°C, and 20 parts by weight of calcium carbonate having an average particle size of 1.5 μm was melt-kneaded in an extruder set at 250°C, and supplied to a co-extrusion die for use as core layer (A).

【００２５】
(2) また、別の２５０℃に設定された押出機にはＭＦＲ１０ｇ／１０分、結晶化度６４％、融点１６７℃のプロピレン単独重合体５２重量部に、平均粒径１．５μｍの炭酸カルシウム４５重量部、酸化チタン３重量部とを配合した組成物（Ｂ）を２４０℃で溶融混練し、共押出ダイに供給し同ダイ内で前記芯材層（Ａ）用組成物の片面に積層される様にしてシート状に押し出し、これを冷却ロールにて６０℃迄冷却して二層構造（Ｂ／Ａ）の無延伸シートを得た。[0025]
(2) In addition, in another extruder set at 250°C, composition (B) containing 52 parts by weight of propylene homopolymer having an MFR of 10 g/10 min, a crystallinity of 64%, and a melting point of 167°C, 45 parts by weight of calcium carbonate having an average particle size of 1.5 μm, and 3 parts by weight of titanium oxide was melt-kneaded at 240°C, supplied to a co-extrusion die, and extruded into a sheet so as to be laminated on one side of the composition for core layer (A) in the die. This was then cooled to 60°C with a cooling roll to obtain an unstretched sheet of a two-layer structure (B/A).

【００２６】
次いで、この二層構造の無延伸シートを１３５℃に設定された周速差の異なるロール群よりなる縦延伸機にて縦方向に５倍延伸し、次いで、１５０℃の温度でアニーリング処理を施し５０℃の温度にまで冷却し耳部をスリットして８０μｍ（Ｂ／Ａ＝７／７３μｍ）の微細な独立したボイドを有する一軸延伸二層フィルム（Ｂ／Ａ）を得た。
この一軸延伸二層フィルムは、ボイド率が２３％、不透明度が８８％であり、また、引張弾性率は延伸方向（縦方向）２９，６００ｋｇｆ／ｃｍ² 、横方向１１，３００ｋｇｆ／ｃｍ² 、引裂方向のエルメンドルフ引裂強度は、１０ｇであった。[0026]
Next, this two-layer unstretched sheet was stretched 5 times in the longitudinal direction using a longitudinal stretching machine consisting of a group of rolls with different peripheral speed differences set at 135°C, and then annealed at a temperature of 150°C, cooled to a temperature of 50°C, and the edge portions were slit to obtain a uniaxially stretched two-layer film (B/A) having fine independent voids of 80 μm (B/A = 7/73 μm).
This uniaxially stretched two-layer film had a void ratio of 23%, an opacity of 88 %, a tensile modulus of elasticity of 29,600 kgf/cm ² in the stretching direction (machine direction) and 11,300 kgf/cm ² in the transverse direction, and an Elmendorf tear strength of 10 g in the tear direction.

【００２８】
【発明の効果】
各個片の引裂性に優れた結束紐を提供することができた。[0028]
[Effects of the Invention]
It was possible to provide a binding cord with excellent tear resistance for each individual piece.

Claims

A multilayer film is prepared by laminating, on at least one side of a core layer (A) based on a resin composition containing 70 to 99% by weight of a crystalline polyolefin ( _A1 ) _and 30 to 1% by weight of an inorganic fine powder ( _A2 ), a surface layer ( _B ) made of a resin composition containing 35 to 60% by weight of an inorganic fine powder (B2) and 65 to 40% by weight of a crystalline polyolefin (B1), and stretching the multilayer film uniaxially by 3 to 10 times at a temperature lower than the melting points of the crystalline polyolefins ( _A1 , _B1 ) to form a large number of fine voids. The uniaxially stretched multilayer film has an opacity (JIS P-8138 ) of 70% or more and an Elmendorf tear strength (JIS A binding cord comprising a uniaxially oriented multilayer film having a surface layer (B) printed with 5 to 15 g of a uniaxially oriented multilayer film (K-7128) and a pressure-sensitive adhesive layer provided on the back surface of the uniaxially oriented multilayer film opposite to the printed surface.

The binding cord described in claim 1, characterized in that each piece can be torn linearly in a uniform width by tearing it in opposite directions with fingers from a group of binding cords that have notches (cuts) so that the tearing stress is concentrated in the stretching direction (machine direction, longitudinal direction) of the uniaxially stretched multilayer film, resulting in individual binding cords.