JPH051135B2

JPH051135B2 -

Info

Publication number: JPH051135B2
Application number: JP9625885A
Authority: JP
Inventors: Masayuki Inoe
Original assignee: Yupo Corp
Current assignee: Yupo Corp
Priority date: 1985-05-07
Filing date: 1985-05-07
Publication date: 1993-01-07
Also published as: JPS61254337A

Description

[Detailed description of the invention]

〔産業上の利用分野〕本発明は、つかいすておむつ、生理用ナプキ
ン、電解隔膜等に有用な表面強度の優れる通気性
を有する多孔性樹脂積層フイルムに関する。〔従来技術〕生理用ナプキン、つかいすておむつにおいて、
通気性と防水性を有するポリオレフイン系多孔樹
脂フイルムが防漏材として使用されている。かかる多孔樹脂フイルムは、高密度ポリエチレ
ン、線状ポリエチレンまたは両者の混合物を樹脂
素材とし、これに炭酸カルシウム、酸化チタン、
焼成クレイ、けいそう土等の無機微細粉末、必要
により液状ブタジエンゴム、液状イソブチレンゴ
ム、液状ポリエチレンワツクス等の柔軟性改良剤
を配合した組成物を押出機を用いてフイルム状に
溶融成形後、マンドレル、ロール群の周速差を利
用した延伸装置、またはテンターを用いて延伸成
形することにより製造されている（特開昭57−
47334号、同57−203520号、同58−15538号、同58
−149925号、同58−149303号、同59−62117号、
同59−140235号、同60−6442号）。この微多孔樹脂フイルムは通気性、防漏性に富
むものでつかいすておむつの防水性カバーとして
有用である。〔従来技術の問題点〕この多孔樹脂フイルムは無機微細粉末を核とし
て微細な連続空孔を多数有し、表面には大気に連
通した空隙を有するもので通気性に富むもので、
つかいすておむつの防水カバーシートとして有用
である。この多孔樹脂フイルムをつかいすておむつの防
水カバーシートとして用いるとき、表面に離型紙
を備えた両面粘着テープが止め具として用いられ
赤ちやんの股につかいすておむつを装着した後、
両面粘着テープの表面の離型紙を引き剥し、露呈
した粘着剤で粘着してつかいすておむつを固定す
る。この粘着テープを多孔樹脂フイルムの誤つた位
置に貼合した場合または貼合した位置を少しずら
せたいとき、粘着テープを貼着しなおすためにつ
かいすておむつより剥離すると、従来の多孔樹脂
フイルムは表面に無機微細粉末が突出もしくは樹
脂フイルム基材に付着して露出しているので、こ
の無機微細粉末が粘着テープの粘着面に移動し、
粘着テープの粘着力を低下させる原因となつた
り、多孔樹脂フイルムの表面強度が低いためにフ
イルム表面が剥離したりする問題がある。〔問題点を解決するための具体的手段〕本発明においては、多孔樹脂フイルムを複層構
造とし、粘着テープが貼着される表面層を無機微
細粉末の量が極めて少ないものとすることにより
表面強度を向上させるとともに粘着テープへ移行
する無機微細粉末の量を低下させることにより前
記問題点を解決させ、かつ、多孔性フイルムが通
気性を有するという課題を表面層の肉厚を極めて
薄くすることにより表面層にも大気に連通する空
隙を存在させることにより複層フイルムに通気性
の機能を備えさせるものである。即ち、本発明は、無機微細粉末を50〜75重量％
の割合で含有するポリオレフインの２軸延伸多孔
フイルム(A)を基材層として含み、無機微細粉末を
55〜75重量％の割合で含有するポリオレフインの
延伸多孔フイルム(B)とポリオレフインの延伸フイ
ルムであつて、この延伸フイルムの肉厚が(B)のフ
イルム中に存在する無機微細粉末の平均粒径の1/
１０から１倍である表面層(C)のラミネート物を含む
多孔性樹脂積層フイルムであつて、この多孔性樹
脂積層フイルムの20℃における透気度は40〜7000
秒であり、20℃における透湿度は100〜10000ｇ、
24時間１気圧であることを特徴とする多孔性樹脂
積層フイルムを提供するものである。（樹脂）本発明の実施において、各(A)、(B)および(C)層の
樹脂素材としてのポリオレフインとしては高密度
ポリエチレン、線状ポリエチレン、低密度ポリエ
チレン、ポリプロピレン、エチレン・プロピレン
共重合体、ポリブテン等のポリオレフインまたは
これら２種以上の混合物があげられ、特に、つか
いすておむつの防水カバーシートを考えた場合、
比重が0.92〜0.97、メルトインデツクス（MI）が
0.06〜１ｇ／10分（190℃）の高密度ポリエチレ
ンおよび／または比重が0.91〜0.94、MIが0.5〜
10ｇ／10分、線状ポリエチレンを用いたときは、
得られる多孔樹脂フイルムの風合、肌ざわりがよ
い。（無機微細粉末）無機微細粉末としては、平均粒径が20ミクロン
以下、好ましくは３ミクロン以下のものが用いら
れ、炭酸カルシウム、けいそう土、焼成クレイ、
けい酸アルミニウム、タルク等があげられる。（任意成分）ポリオレフイン、無機微細粉末の他に必要によ
り安定剤、顔料、分散剤、帯電防止剤、液状ブタ
ジエンゴム、ポリエチレンワツクス、液状イソブ
チレンゴム、アタツクポリプロピレン、ジブチル
フタレート、液状水添ヒマシ油等を配合してよ
い。（積層フイルム）多孔積層フイルムは、無機微細粉末を50〜75重
量％含有するポリオレフイン(A)を押出機で溶融混
練し、ダイよりシート状に押し出し、ポリオレフ
インの融点より低い温度にシートを冷却後、延伸
できる温度に加熱し（通常、融点より３〜35℃低
い温度）、ロール群の周速差を利用して縦方向に
1.3〜７倍、好ましくは1.8〜５倍延伸した後、こ
の縦延伸フイルムの片面または両面に、無機微細
粉末を55〜75重量％含有するポリオレフイン(B)フ
イルムと無機微細粉末含量が０〜３重量％である
ポリオレフイン(C)フイルムとの溶融ラミネート物
を溶融積層し、この積層フイルムをポリオレフイ
ンの融点より低い温度に冷却後、テンターを用い
て1.5〜10倍、好ましくは２〜７倍横方向に延伸
し、ついで必要により熱処理したのち、冷却し、
耳部をスリツトすることにより製造される。この際、重要なことは横延伸された後の表面層
(C)のフイルムの肉厚が、(B)のフイルム中に分散す
る無機微細粉末の平均粒径の1/10から１倍の肉厚
となるように溶融ラミネート物の(C)のフイルム肉
厚および延伸倍率を選択することである。即ち、表面層(C)の延伸フイルムは、これ単層の
みでは押出されるフイルムの肉厚が薄すぎて均一
な肉厚のフイルムを得ることが困難であり、また
延伸が困難である。そこで、(C)のフイルムより厚
肉のフイルム(B)を一台のダイより(C)のフイルムと
ともに共押出し、フイルム成形性、延伸性を容易
とする。なお、表面層(C)のフイルムの肉厚を厚くするこ
とができないのは、積層フイルムに通気性をもた
らすために無機微細粉末を含有しない、もしくは
微量に含有する表面層(C)が通気性を有するために
大気に連通する空孔を有することが必要であり、
この大気に連通する空孔を延伸により表面層(C)に
形成させるのに(B)のフイルム中に存在する微細粉
末を利用しているからである。この積層フイルムは、JIS Ｚ−0208により20℃
で測定した透湿度が100〜10000ｇ／m²・24時間・
１気圧、好ましくは200〜5000ｇ／m²・24時間・
１気圧であり、次の方法で測定した20℃における
透気度が40〜7000秒、好ましくは100〜2000秒で
ある。透気度の測定法 JIS Ｐ−8117に準拠して使られた王研式透気度
（平滑度試験機（旭精工製）を用いて測定）透気度、透湿度が前範囲を外れると、この多孔
性積層フイルムをおむつの防水カバーや使いすて
生理用ナプキンの防漏材として用いたとき、むれ
がおきやすいか、防液性がない。（効果）本発明の多孔性積層フイルムは、２軸延伸フイ
ルム基材層(A)を含むので強度バランスに優れ、ク
リープ伸びや引き裂きが少ない。また、表面層(C)
もフイルム(B)層の無機微細粉末が突出し、マツト
調（粗面）となつているので、この多孔性樹脂積
層フイルムをエンボス加工したものは外観が布に
近く、かつ、手触りが良好である。また、突出し
た(B)層の無機微細粉末も(C)層のフイルムの存在に
より積層フイルムより脱落しにくくなつており、
紙粉トラブル（粘着テープの再接着不良）が生じ
難い。実施例１ (1) 密度0.92ｇ／cm²、メルトインデツクス1.0
ｇ／10分の線状ポリエチレン10重量部、密度
0.95ｇ／cm²、メルトインデツクス0.8ｇ／10分
の高密度ポリエチレン25重量部および平均粒径
1.8ミクロンの炭酸カルシウム65重量部よりな
る樹脂組成物(A)を押出機を用いて溶融混練し、
220℃でダイよりシート状に押し出し、このシ
ートを70℃まで冷却後、110℃まで加熱し、ロ
ール群の周速差を利用して縦方向に2.5倍延伸
し、縦延伸フイルムを得た。 (2) 密度0.92ｇ／cm²、メルトインデツクス1.0
ｇ／10分の線状ポリエチレン10重量部、密度
0.95ｇ／cm²、メルトインデツクス0.8ｇ／10分
の高密度ポリエチレン25重量部および平均粒径
1.8ミクロンの炭酸カルシウム65重量部よりな
る樹脂組成物(B)と、前記線状ポリエチレン40重
量部と前記高密度ポリエチレン60重量部よりな
る樹脂組成物(C)とを、それぞれ別々の押出機を
用いて溶融混練し、それぞれ一台のダイに供給
し、ダイ内ラミさせた。このラミネート物をシート状に共押出し、前記
(1)で得た縦延伸フイルムの両面に積層し、60℃ま
で冷却し、ついで加熱オーブン内に導き、約117
℃まで加熱した後、テンターを用いて横方向に３
倍延伸し、これを120℃で熱処理した後、50℃ま
で冷却し、耳部をスリツトして(C)／(B)／(A)／(B)／
(C)の各肉厚が0.5μ／20μ／40μ／20μ／0.5μの５層
積層フイルムを得た。この積層フイルムの透気度（20℃）、透湿度
（20℃）および紙粉トラベル度を表１に示す。なお、紙粉トラブル度は次の方法により測定し
た。粘着テープ“セロフアンテープ”（ニチバン製
商品名、LP−18）をフイルム面に貼着し親指の
腹で５回こすつた後、テンシロン（東洋ボールド
ボーウイン製）で200mm／分の速度で粘着テープ
を剥離した。この粘着テープの透光量をカラーメーター（ス
ガ試験機製）で測定した。予め、粘着する前の粘着テープの透光量をブラ
ンク値として測定しておき、これで前記値を除し
たものを透光率とした（値の大きいものほど紙粉
トラブルは少ない）。透光率が80％の以下のものは透光率の他に若干
問題有りと付記し、また70％以下のものは不良と
付記した。また、剥離の時多孔樹脂フイルム表面層が破断
して透光率の測定不能なものは紙ムケ不良と記し
た。実施例２〜７、比較例１〜３各組成物の割合を表１に示すように変化、また
は各層の肉厚を同表に示すようにする他は、実施
例１と同様にして３層または５層積層フイルムを
得た。これら積層フイルムの透気度、透湿度および紙
粉トラブル度を同表に示す。 [Industrial Field of Application] The present invention relates to a porous resin laminated film having excellent surface strength and air permeability, useful for disposable diapers, sanitary napkins, electrolytic diaphragms, etc. [Prior art] In sanitary napkins and disposable diapers,
Polyolefin porous resin film, which has breathability and waterproof properties, is used as a leak-proof material. Such porous resin film uses high-density polyethylene, linear polyethylene, or a mixture of both as a resin material, and contains calcium carbonate, titanium oxide,
After melt-molding a composition containing fine inorganic powder such as fired clay or diatomaceous earth and, if necessary, a flexibility improver such as liquid butadiene rubber, liquid isobutylene rubber, or liquid polyethylene wax, into a film using an extruder, It is manufactured by stretching and forming using a mandrel, a stretching device that utilizes the difference in circumferential speed between a group of rolls, or a tenter (Japanese Patent Laid-Open No. 1983-1999).
No. 47334, No. 57-203520, No. 58-15538, No. 58
−149925, No. 58-149303, No. 59-62117,
59-140235, 60-6442). This microporous resin film is highly breathable and leakproof, and is useful as a waterproof cover for disposable diapers. [Problems with the prior art] This porous resin film has a large number of fine continuous pores with a core of inorganic fine powder, and the surface has voids that communicate with the atmosphere, making it highly breathable.
It is useful as a waterproof cover sheet for disposable diapers. When this porous resin film is used as a waterproof cover sheet for disposable diapers, a double-sided adhesive tape with release paper on the surface is used as a fastener, and after the diaper is attached to the baby's crotch,
Peel off the release paper on the surface of the double-sided adhesive tape and use the exposed adhesive to secure the disposable diaper. When this adhesive tape is attached to the wrong position of the porous resin film or when you want to slightly shift the attached position, when you use it to reapply the adhesive tape and peel it off from the diaper, the conventional porous resin film will Since the inorganic fine powder is exposed on the surface by protruding or adhering to the resin film base material, this inorganic fine powder moves to the adhesive surface of the adhesive tape,
There are problems in that it causes a decrease in the adhesive strength of the adhesive tape, and that the surface of the porous resin film peels off because the surface strength of the porous resin film is low. [Specific means for solving the problem] In the present invention, the porous resin film has a multilayer structure, and the surface layer to which the adhesive tape is attached has an extremely small amount of inorganic fine powder. To solve the above problems by improving the strength and reducing the amount of inorganic fine powder transferred to the adhesive tape, and to solve the problem of the porous film having air permeability by making the thickness of the surface layer extremely thin. This allows the multilayer film to have an air permeability function by providing voids communicating with the atmosphere in the surface layer as well. That is, the present invention uses 50 to 75% by weight of inorganic fine powder.
The base layer includes a biaxially stretched porous film (A) of polyolefin containing a proportion of
A stretched porous film (B) of polyolefin containing a proportion of 55 to 75% by weight, and a stretched film of polyolefin in which the thickness of the stretched film is (B).The average particle size of the inorganic fine powder present in the film. 1/ of
This is a porous resin laminated film including a laminate of the surface layer (C) that is 10 to 1 times as large, and the air permeability of this porous resin laminated film at 20°C is 40 to 7000.
seconds, and the moisture permeability at 20℃ is 100 to 10,000g,
The present invention provides a porous resin laminated film which is characterized by being kept under a pressure of 1 atm for 24 hours. (Resin) In the practice of the present invention, the polyolefin used as the resin material for each layer (A), (B), and (C) includes high-density polyethylene, linear polyethylene, low-density polyethylene, polypropylene, and ethylene-propylene copolymer. , polyolefins such as polybutene, or mixtures of two or more of these, especially when considering waterproof cover sheets for disposable diapers.
Specific gravity is 0.92-0.97, melt index (MI) is
High density polyethylene of 0.06~1g/10min (190℃) and/or specific gravity 0.91~0.94, MI 0.5~
10g/10 minutes, when using linear polyethylene,
The resulting porous resin film has a good texture and texture. (Inorganic fine powder) As the inorganic fine powder, those having an average particle size of 20 microns or less, preferably 3 microns or less are used, and include calcium carbonate, diatomaceous earth, calcined clay,
Examples include aluminum silicate and talc. (Optional ingredients) In addition to polyolefin, inorganic fine powder, stabilizers, pigments, dispersants, antistatic agents, liquid butadiene rubber, polyethylene wax, liquid isobutylene rubber, attacking polypropylene, dibutyl phthalate, liquid hydrogenated castor oil as necessary. etc. may be combined. (Laminated film) Porous laminated film is produced by melt-kneading polyolefin (A) containing 50 to 75% by weight of inorganic fine powder in an extruder, extruding it into a sheet from a die, and cooling the sheet to a temperature lower than the melting point of the polyolefin. , heated to a temperature that allows stretching (usually 3 to 35 degrees Celsius lower than the melting point), and then stretched in the longitudinal direction using the difference in circumferential speed of the roll group.
After stretching 1.3 to 7 times, preferably 1.8 to 5 times, a polyolefin (B) film containing 55 to 75% by weight of inorganic fine powder and an inorganic fine powder content of 0 to 3 on one or both sides of the longitudinally stretched film. % by weight of a polyolefin (C) film, and after cooling the laminated film to a temperature lower than the melting point of the polyolefin, it is 1.5 to 10 times, preferably 2 to 7 times, in the lateral direction using a tenter. Stretched, then heat treated if necessary, cooled,
Manufactured by slitting the ears. At this time, the important thing is that the surface layer after horizontal stretching is
The film thickness of (C) of the melt laminate is adjusted so that the thickness of the film (C) is 1/10 to 1 times the average particle size of the inorganic fine powder dispersed in the film (B). It is a matter of selecting the thickness and stretching ratio. That is, when the stretched film of the surface layer (C) is a single layer, the thickness of the extruded film is too thin, and it is difficult to obtain a film with a uniform thickness, and it is also difficult to stretch the film. Therefore, the film (B), which is thicker than the film (C), is coextruded with the film (C) through a single die to facilitate film moldability and stretchability. The reason why it is not possible to increase the thickness of the surface layer (C) is because the laminated film does not contain inorganic fine powder to provide air permeability, or the surface layer (C) containing a small amount of inorganic powder is air permeable. In order to have this, it is necessary to have holes that communicate with the atmosphere,
This is because the fine powder present in the film (B) is used to form pores communicating with the atmosphere in the surface layer (C) by stretching. This laminated film is rated at 20℃ according to JIS Z-0208.
Moisture permeability measured at 100 to 10,000 g/ ^m2 , 24 hours,
1 atm, preferably 200-5000g/m ² 24 hours
The pressure is 1 atm, and the air permeability at 20°C measured by the following method is 40 to 7000 seconds, preferably 100 to 2000 seconds. Air permeability measurement method Oken type air permeability used in accordance with JIS P-8117 (measured using a smoothness tester (manufactured by Asahi Seiko)) If the air permeability and moisture permeability are out of the previous range When this porous laminated film is used as a waterproof cover for diapers or as a leak-proof material for disposable sanitary napkins, it tends to get stuffy or lacks liquid-proof properties. (Effects) Since the porous laminated film of the present invention includes the biaxially stretched film base layer (A), it has excellent strength balance and less creep elongation and tearing. In addition, the surface layer (C)
The fine inorganic powder of the film (B) layer protrudes and has a matte-like (rough surface), so products embossed with this porous resin laminated film look similar to cloth and have a good feel. . In addition, the inorganic fine powder in the protruding layer (B) is less likely to fall off than the laminated film due to the presence of the film in the (C) layer.
Paper dust problems (poor adhesive tape re-adhesion) are less likely to occur. Example 1 (1) Density 0.92g/cm ² , Melt index 1.0
g/10 min linear polyethylene 10 parts by weight, density
25 parts by weight of high-density polyethylene of 0.95 g/cm ² , melt index 0.8 g/10 min and average particle size
A resin composition (A) consisting of 65 parts by weight of 1.8 micron calcium carbonate is melt-kneaded using an extruder,
It was extruded into a sheet through a die at 220°C, cooled to 70°C, heated to 110°C, and stretched 2.5 times in the longitudinal direction using the difference in circumferential speed between the roll groups to obtain a longitudinally stretched film. (2) Density 0.92g/cm ² , Melt index 1.0
g/10 min linear polyethylene 10 parts by weight, density
25 parts by weight of high-density polyethylene of 0.95 g/cm ² , melt index 0.8 g/10 min and average particle size
A resin composition (B) consisting of 65 parts by weight of calcium carbonate of 1.8 microns and a resin composition (C) consisting of 40 parts by weight of the linear polyethylene and 60 parts by weight of the high-density polyethylene were each run in separate extruders. The materials were melted and kneaded, each supplied to one die, and laminated inside the die. This laminate is coextruded into a sheet, and the
Laminated on both sides of the longitudinally stretched film obtained in (1), cooled to 60℃, then introduced into a heating oven,
After heating to ℃, use a tenter to horizontally
After stretching it twice and heat treating it at 120°C, it was cooled to 50°C and the edges were slit.(C)／(B)／(A)／(B)／
A five-layer laminated film (C) having thicknesses of 0.5μ, 20μ, 40μ, 20μ, and 0.5μ was obtained. Table 1 shows the air permeability (20°C), moisture permeability (20°C), and paper powder travel of this laminated film. The degree of paper dust trouble was measured by the following method. Adhesive tape "Cellophane Tape" (trade name, LP-18 manufactured by Nichiban) was applied to the film surface, rubbed 5 times with the pad of the thumb, and then adhered at a speed of 200 mm/min with Tensilon (manufactured by Toyo Bold Bowin). The tape was peeled off. The amount of light transmitted through this adhesive tape was measured using a color meter (manufactured by Suga Test Instruments). The amount of light transmitted through the adhesive tape before adhesion was measured as a blank value in advance, and the value divided by this value was defined as the light transmittance (the larger the value, the less paper dust trouble occurs). Items with a light transmittance of 80% or less were noted as having some problems in addition to the light transmittance, and items with a light transmittance of 70% or less were noted as defective. In addition, when the surface layer of the porous resin film was broken during peeling and the light transmittance could not be measured, it was described as a paper smudge defect. Examples 2 to 7, Comparative Examples 1 to 3 Three layers were prepared in the same manner as in Example 1, except that the proportions of each composition were changed as shown in Table 1, or the thickness of each layer was changed as shown in Table 1. Alternatively, a 5-layer laminated film was obtained. The air permeability, moisture permeability, and paper powder trouble level of these laminated films are shown in the same table.

【表】【table】

【table】

Claims

[Claims] 1. A biaxially stretched porous film (A) of polyolefin containing 50 to 75% by weight of inorganic fine powder as a base layer; A stretched porous film of polyolefin containing (B) and a stretched film of polyolefin,
This stretched film is a porous resin laminated film including a laminate of a surface layer (C) in which the wall thickness of the stretched film is 1/10 to 1 times the average particle size of the inorganic fine powder present in the film (B). The air permeability of this porous resin laminated film at 20℃ is 40 to 7000 seconds, and at 20℃
A porous resin laminated film having a moisture permeability of 100 to 10,000 g/m ² and a pressure of 1 atm for 24 hours. 2. The porous resin laminated film according to claim 1, wherein the surface layer (C) has a wall thickness of 0.2 to 3 microns. 3 The material resin for the base layer (A) is 50 to 85% by weight of high-density polyethylene with a specific gravity of 0.92 to 0.97 and a melt index of 0.06 to 1 g/10 minutes, and 50 to 85% by weight of high-density polyethylene with a specific gravity of 0.91 to 0.94 and a melt index of 0.5 to 10 g/10 minutes. The porous resin laminated film according to claim 1, which is a mixture of 50 to 15% by weight of linear polyethylene. 4 Film (B) and film (C) have a stretching ratio of 1.2 to 3.5
The porous resin laminated film according to claim 1, which is a double uniaxially stretched film.