JPH0531803A - Manufacture of antistatic polyethylene crosslinking oriented film - Google Patents
Manufacture of antistatic polyethylene crosslinking oriented filmInfo
- Publication number
- JPH0531803A JPH0531803A JP3211383A JP21138391A JPH0531803A JP H0531803 A JPH0531803 A JP H0531803A JP 3211383 A JP3211383 A JP 3211383A JP 21138391 A JP21138391 A JP 21138391A JP H0531803 A JPH0531803 A JP H0531803A
- Authority
- JP
- Japan
- Prior art keywords
- antistatic agent
- film
- crosslinking
- sheet
- antistatic
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Pending
Links
Landscapes
- Extrusion Moulding Of Plastics Or The Like (AREA)
- Shaping By String And By Release Of Stress In Plastics And The Like (AREA)
- Laminated Bodies (AREA)
- Processing And Handling Of Plastics And Other Materials For Molding In General (AREA)
Abstract
Description
【０００１】[0001]
【産業上の利用分野】本発明は帯電防止性ポリエチレン
架橋延伸フィルムの製法に関し、特に、特殊架橋構成の
フイルムであるとともに、その帯電防止性能を最大限に
発揮することができるポリエチレンフィルムの製法に関
する。BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing an antistatic polyethylene crosslinked stretched film, and more particularly to a method for producing a polyethylene film which is a film having a special crosslinking structure and which can maximize its antistatic performance. .
【０００２】[0002]
【従来の技術】従来、高い結晶化度を有するポリエチレ
ンフィルムに帯電防止性能を付与するためには、一旦成
形したフィルム表面に帯電防止剤を塗布するか、あるい
は、帯電防止剤を原料樹脂に練り込んだ後フィルムに成
形するなどの方法が知られていた。帯電防止剤を塗布す
る場合は、基材となるポリエチレンフィルムに帯電防止
剤を含む基材との接着性の良い積層樹脂を、有機溶剤も
しくは水などに溶解し、この溶液を含浸法、グラビアコ
−ト法などにより塗布し、乾燥するなどして帯電防止性
を付与していたが、その効果の持続性やアンチブロッキ
ング性が劣るという問題があった。そこで、帯電防止剤
を原料樹脂に練り込む方法が考えられるが、これは帯電
防止剤を直接もしくは通常の１０倍程度の濃度の帯電防
止剤を含むマスタ−バッチとして、原料樹脂とともにホ
ッパ−内に投入し、単層ダイを通して溶融押出成形し、
帯電防止剤の濃度がフィルムの厚み方向に対して均一な
フィルムを製膜し、場合によってＭＤ（機械方向）もし
くはＴＤ（機械方向に対する直角方向）に延伸した後コ
ロナ処理を施し、しかる後にエ−ジングを行って、帯電
防止剤をフィルム表面に移行させることにより、帯電防
止性能を発現させていた。2. Description of the Related Art Conventionally, in order to impart antistatic performance to a polyethylene film having a high degree of crystallinity, an antistatic agent is applied to the surface of a film once molded, or an antistatic agent is kneaded into a raw material resin. A method of forming a film after incorporating it was known. When applying an antistatic agent, a layered resin with good adhesion to the base material containing the antistatic agent is dissolved in an organic solvent or water, and then this solution is impregnated by the impregnation method or gravure coating. Although the antistatic property was imparted by applying it by the G-method and then drying it, there was a problem that the durability of the effect and the antiblocking property were poor. Therefore, a method of kneading the antistatic agent into the raw material resin can be considered. This is a method in which the antistatic agent is directly or as a master batch containing the antistatic agent at a concentration of about 10 times the normal concentration, and is placed in the hopper together with the raw material resin. Input, melt extrusion molding through single layer die,
A film having a concentration of the antistatic agent uniform in the thickness direction of the film is formed, and in some cases, MD (machine direction) or TD (direction perpendicular to the machine direction) is stretched, and then corona treatment is performed. The antistatic performance was exhibited by aging and transferring the antistatic agent to the film surface.
【０００３】一方、従来、高密度ポリエチレンは、結晶
性が大きく、高い融点を示すばかりでなく優れた機械的
性質、化学的性質をもつ材料であるが、得られるフイル
ムは一般に不透明で、防湿性などが悪いものであった。
この高密度ポリエチレンの透明性を改善するために、放
射線などで均一に架橋を行ったポリエチレン延伸フイル
ムが提案されたが、当該方法による架橋延伸ポリエチレ
ンフイルムは、その透明性および強度は改善されるもの
の、防湿性やアンチブロッキング性については十分でな
く、防湿性の要求される用途においてはフイルムの厚さ
を増したり、バリヤー性樹脂層を設けることが必要で、
そのためフイルムの透明性や包装特性などを損い、ま
た、製造コストを高いものにし、さらに、透明性の改善
される程度に架橋されたポリエチレン延伸フイルムは、
低温ヒートシール性が損われるなどという欠点があり、
包装材などとしての機能は必ずしも十分ではなかった。
本発明者らは、先に、例えば、シ−ト状原反の両面から
電子線を照射するなどして、その架橋構成において、例
えば、両表層は架橋された架橋層であるが、内層の中間
層は未架橋層であるようなその架橋度がフイルムの厚さ
方向において、中方向に低下した架橋ポリエチレン延伸
フイルムを提案した。この特殊架橋構成のポリエチレン
延伸フイルムによれば、透明度（ヘイズ値）が高く、か
つ、防湿性に優れているなど従来の問題点を解消するこ
とができたものを得ることができた。On the other hand, conventionally, high-density polyethylene is a material having not only high crystallinity and high melting point but also excellent mechanical and chemical properties, but the obtained film is generally opaque and moisture-proof. Was bad.
In order to improve the transparency of this high-density polyethylene, a polyethylene stretched film that has been uniformly crosslinked by radiation or the like has been proposed, but the crosslinked stretched polyethylene film obtained by the method has improved transparency and strength. , The moisture resistance and anti-blocking properties are not sufficient, and it is necessary to increase the thickness of the film or provide a barrier resin layer in applications where moisture resistance is required.
Therefore, the transparency and packaging characteristics of the film are impaired, the manufacturing cost is increased, and the polyethylene stretched film crosslinked to the extent that the transparency is improved is
There is a drawback that the low temperature heat sealability is impaired,
The function as a packaging material was not always sufficient.
In the cross-linking structure of the sheet-shaped sheet, for example, by irradiating electron beams from both sides of the sheet-shaped raw fabric, the surface layers of the inner layer are cross-linked layers. We proposed a cross-linked polyethylene stretched film in which the degree of cross-linking was such that the intermediate layer was an uncross-linked layer, and the degree of cross-linking decreased in the middle direction in the thickness direction of the film. According to the stretched polyethylene film having the special cross-linking structure, it is possible to obtain a product which can solve the conventional problems such as high transparency (haze value) and excellent moisture resistance.
【０００４】しかしながら、このポリエチレンフィルム
に、帯電防止性を付与するために、前述のように、帯電
防止剤を原料樹脂に練り込み、単層ダイを通して、帯電
防止剤の濃度がフィルムの厚み方向に対して均一なシ−
ト状原反を溶融押出成形し、このものに上記のように電
子線を照射し、架橋度がフィルムの厚さ方向において、
内側に低下したポリエチレン延伸フィルムを成形する
と、電子線がフィルム表面付近の帯電防止剤を分解する
ために、加えた帯電防止剤の表面付近に存在するものの
多くは無駄になり、しかも、電子線の架橋効率も低減し
てしまうことが分かり、このため、十分な帯電防止効果
を発現させるためには、必要以上の帯電防止剤を添加す
ることなどにより対処せざるを得なかった。この必要以
上の帯電防止剤の添加はコスト的にも問題があり、しか
も、照射された電子線のある程度は、この帯電防止剤の
分解に消費されるため、効率の良い架橋が行われていな
かった。However, in order to impart antistatic properties to this polyethylene film, as described above, the antistatic agent is kneaded into the raw material resin, and the concentration of the antistatic agent is passed through the single layer die in the thickness direction of the film. On the other hand, a uniform seam
Melt extrusion molding of sheet-shaped raw material, irradiating this with electron beam as described above, the degree of crosslinking in the thickness direction of the film,
When a stretched polyethylene stretched film is molded inside, the electron beam decomposes the antistatic agent near the film surface, so many of the existing antistatic agent near the surface are wasted, and the electron beam It was found that the cross-linking efficiency was also reduced, and therefore, in order to exert a sufficient antistatic effect, it was unavoidable to add an antistatic agent more than necessary. The addition of more antistatic agent than this is problematic in terms of cost, and moreover, some of the irradiated electron beam is consumed for the decomposition of this antistatic agent, so that efficient crosslinking is not performed. It was
【０００５】[0005]
【発明が解決しようとする課題】本発明は、かかる技術
背景の下、種々の優れた特性を有する架橋度がフイルム
の厚さ方向に低下したポリエチレン架橋延伸フイルムに
ついて、その帯電防止性能を最大限に発揮することがで
きる技術を提供することを目的とする。本発明の他の目
的及び新規な特徴は本明細書全体の記述からも明らかと
なるであろう。SUMMARY OF THE INVENTION Under the above-mentioned technical background, the present invention provides a polyethylene crosslinked stretched film having various excellent properties and having a reduced degree of crosslinking in the thickness direction of the film, and its antistatic performance is maximized. The purpose is to provide a technology that can be used to Other objects and novel features of the present invention will be apparent from the entire description of the specification.
【０００６】[0006]
【課題を解決するための手段】本発明は、中間層には帯
電防止剤を含有しているが、両表層には帯電防止剤を含
有していないポリエチレンよりなるシ−ト状原反または
チュ−ブ状原反を、少なくとも三層の共押出しにより成
形後、当該原反の厚さ方向において中方向に架橋度が低
下するように架橋させた後、少なくとも一方向に延伸を
行なうことを特徴とする帯電防止性ポリエチレン架橋延
伸フィルムの製法に係るものである。According to the present invention, a sheet-like raw sheet or a tuft made of polyethylene which contains an antistatic agent in the intermediate layer but does not contain an antistatic agent in both surface layers. -The bubby original fabric is formed by coextrusion of at least three layers, and then crosslinked so that the degree of crosslinking decreases in the middle direction in the thickness direction of the original fabric, and then stretched in at least one direction. And a method for producing an antistatic polyethylene crosslinked stretched film.
【０００７】次に、本発明について、詳述する。本発明
において、中間層には帯電防止剤を含有しているが、両
表層には帯電防止剤を含有していないポリエチレンより
なるシ−ト状原反またはチュ−ブ状原反を得るには、帯
電防止剤を含有したポリエチレン樹脂層と、それを含有
しないポリエチレン樹脂層とを積層することにより、行
なうことができる。積層方法としては、インフレ−ショ
ン法、カレンダ−法あるいはＴ−ダイ法などで行なうこ
とができ、例えば、当該両樹脂をインフレ−ション法あ
るいはＴ−ダイ法もしくは環状ダイで共押出し、ダイス
内あるいはダイス外で溶融接着して複合化する方法など
各種の方法を採用できる。しかし、作業性、複合化の容
易性などを考慮すると、Ｔ−ダイ法で行なうことが好ま
しく、当該二種三層共押しダイのコア層（中間層）のみ
に帯電防止剤を練り込み、他のスキン層（表層）には帯
電防止剤を練り込まないようにして、シ−ト状あるいは
チュ−ブ状原反を得るようにするとよい。この場合、コ
ア層と両スキン層（各スキン層）との厚み構成比率が、
同じであってもよいが、帯電防止能をより一層発現させ
るなどのためには、コア層の厚みを他のスキン層に比し
て厚く構成することが好ましい。本発明に使用される帯
電防止剤としては、特に限定されるものではなく、例え
ばアニオン系、カチオン系、非イオン系、両性などの各
種界面活性剤、無機塩、多価アルコ−ル、金属化合物な
どの一種または二種以上を用いることができる。これら
帯電防止剤は、フイルム全層において０．０５〜３．０
重量％となるように、コア層に配合することが好まし
い。通常コア層には０．１〜５．０重量％程度の帯電防
止剤を配合するのが好ましい。Next, the present invention will be described in detail. In the present invention, to obtain a sheet-shaped raw material or a tube-shaped raw material made of polyethylene which contains an antistatic agent in the intermediate layer but does not contain an antistatic agent in both surface layers. It can be carried out by laminating a polyethylene resin layer containing an antistatic agent and a polyethylene resin layer not containing the antistatic agent. As a laminating method, an inflation method, a calender method, a T-die method, or the like can be used. For example, the both resins are coextruded by an inflation method, a T-die method, or an annular die, and then, in a die or Various methods such as a method of forming a composite by fusion bonding outside the die can be adopted. However, considering workability, easiness of compounding, etc., it is preferable to carry out by the T-die method, in which the antistatic agent is kneaded only in the core layer (intermediate layer) of the two-kind three-layer co-extrusion die, It is advisable not to knead the antistatic agent into the skin layer (surface layer) of (1) to obtain a sheet-shaped or tube-shaped raw material. In this case, the thickness composition ratio of the core layer and both skin layers (each skin layer) is
Although it may be the same, it is preferable that the core layer is thicker than the other skin layers in order to further develop the antistatic ability. The antistatic agent used in the present invention is not particularly limited, and examples thereof include various surfactants such as anionic, cationic, nonionic and amphoteric agents, inorganic salts, polyhydric alcohols, metal compounds. 1 type or 2 or more types can be used. These antistatic agents are used in an amount of 0.05 to 3.0 in all film layers.
It is preferable that the core layer is blended with the core layer so that the weight percent is obtained. Usually, it is preferable to add about 0.1 to 5.0% by weight of an antistatic agent to the core layer.
【０００８】本発明における原反を構成するポリエチレ
ンとしては、エチレンの単独重合体またはエチレン含量
が５０重量％以上であるエチレンとα−オレフィン、例
えばプロピレン、１−ブテン、１−ペンテン、１−ヘキ
セン、４−メチル−１−ペンテン、１−オクテン、１−
デセンなどとの共重合体があげられる。これらのうちで
は、中低圧法で製造された結晶性のポリエチレンで、密
度が0.935g/cm3 以上、好ましくは0.950g/cm3 以上で、
メルトインデックス（ＪＩＳ Ｋ６７６０により温度１
９０℃荷重２１６kgで測定、以下ＭＩという）が0.05ｇ
／１０分以上、好ましくは0.5 〜２０ｇ／１０分である
高密度ポリエチレンが好ましい。また、高密度ポリエチ
レンの含量が６０重量％以上の低密度ポリエチレンや他
のポリオレフィンとの混合物も使用することができる。
なお、これらポリエチレンには必要に応じて酸化防止
剤、紫外線吸収剤、滑剤、アンチブロッキング剤、顔
料、染料などの公知の添加剤を加えることができる。The polyethylene constituting the raw fabric in the present invention is a homopolymer of ethylene or ethylene and α-olefin having an ethylene content of 50% by weight or more, such as propylene, 1-butene, 1-pentene, 1-hexene. , 4-methyl-1-pentene, 1-octene, 1-
Examples thereof include copolymers with decene and the like. Among these, a crystalline polyethylene produced by the medium- and low-pressure method, the density is 0.935 g / cm 3 or more, preferably 0.950 g / cm 3 or more,
Melt index (Temperature 1 according to JIS K6760
Measured at a load of 216 kg at 90 ° C, hereinafter referred to as MI) is 0.05 g
High-density polyethylene having a density of / 10 minutes or more, preferably 0.5 to 20 g / 10 minutes is preferable. It is also possible to use a mixture of low-density polyethylene having a high-density polyethylene content of 60% by weight or more and other polyolefins.
In addition, known additives such as an antioxidant, an ultraviolet absorber, a lubricant, an anti-blocking agent, a pigment and a dye can be added to these polyethylenes if necessary.
【０００９】シート状原反あるいはチューブ状原反とす
る方法は、通常使用されているＴダイから押出してフラ
ットなシ−ト状原反とする方法、環状ダイから押出して
チューブ状原反とする方法、チューブ状原反を切り開い
てシート状原反とする方法、またはチューブ状原反の両
側を切断して二枚のシート状原反とするなど何れの方法
を用いてもよい。この場合の各原反の厚さは、原反の厚
さ方向において両側から架橋度が中方向に低下するよう
に架橋できる厚さであれば良く、延伸倍率と延伸後のフ
イルムの厚さにより決まるものであるが、通常は２１０
〜２０００μ、好ましくは４００〜１０００μの範囲が
取り扱いおよび前記の架橋を構成させるうえからも望ま
しい。The sheet-shaped raw material or the tube-shaped raw material is extruded from a commonly used T-die to form a flat sheet-shaped raw material, or extruded from an annular die to form a tubular-shaped raw material. Any method may be used, such as a method in which a tube-shaped raw sheet is cut open to form a sheet-shaped original sheet, or both sides of the tube-shaped original sheet are cut to form two sheet-shaped original sheets. In this case, the thickness of each material may be such that it can be crosslinked from both sides in the thickness direction of the material so that the degree of crosslinking decreases in the middle direction, depending on the stretching ratio and the thickness of the film after stretching. It is decided, but usually 210
The range of ˜2000 μ, preferably 400 to 1000 μ is desirable from the viewpoint of handling and constituting the above-mentioned crosslinking.
【００１０】本発明においては、次いで、中間層には帯
電防止剤を含有しているが、両表層には帯電防止剤を含
有していないシ−ト状原反またはチュ−ブ状原反につい
て、原反の厚さ方向において架橋度が中に向って低下す
るように両側から架橋することが必要である。このよう
な架橋を行う方法としては、例えば、原反の両側から電
子線を照射する方法、または架橋剤を配合した（帯電防
止剤については上記の通り）ポリエチレン樹脂の多層共
押出による方法などがあげられる。その架橋度は、ゲル
分率で表わされるが、本発明の目的を達成させるために
は、上記の原反の架橋構成において架橋度最低のゲル分
率が０〜５％未満で、両側各架橋表層のゲル分率が５％
以上、特に２０〜７０％の範囲であることが好ましい。
また、架橋度最低のゲル分率が０％で、原反の厚さ方向
に架橋層／未架橋層／架橋層を構成する場合は、各層の
構成割合が未架橋層：両側各架橋層＝１：0.1 〜１０の
範囲であることが望ましく、特に両側各架橋層の架橋度
が同一であることが好ましい。当該架橋が、原反の厚さ
方向において中方向に架橋度が低下するように架橋が行
われない場合特に架橋度最低のゲル分率が５％を越える
場合には、次いで行なわれる延伸加工が均一に行われ
ず、透明性は改善されるものの防湿性の改善されたフイ
ルムは得られ難い。また、両側各架橋表層の架橋度が、
ゲル分率で２０％未満の場合は延伸加工が均一に行われ
ずフイルムの透明性および防湿性は改善され難い。一
方、ゲル分率が７０％を越える場合は、延伸加工におい
てフイルムが破断し易く円滑な延伸ができ難い。さら
に、原反の厚さ方向全層に均一に架橋が行われた場合に
は延伸加工は均一に行われ透明性は改善されるが防湿性
が改善されず、一方、原反の厚み方向の片側のみの架橋
では延伸加工においてフイルムが破断しやすく、また原
反の厚さ方向の一方から架橋度が低下するように全層に
架橋した場合は、得られるフイルムの防湿性および透明
性の改善が十分ではなく共に好ましくない。なお、上記
のゲル分率は、試料を沸とうｐ−キシレンで抽出し不溶
部分を示したものである。電子線を照射する方法は、原
反の厚さ、樹脂の種類、分子量、分子量分布によっても
異なるが、通常は電子線の照射量を１〜５０メガラッド
（Ｍrad ）、好ましくは５〜２０メガラッドとすればよ
い。また、照射は原反の表裏もしくは内外に同時、また
は表裏もしくは内外に分けて、さらには数回に分けて行
ってもよい。照射線量は、表裏もしくは内外同一線量で
行うことが特に好ましい。さらに、電子線に透過能の調
整は、原反厚さに対する印加電圧の調整、遮へい板によ
るマスキングなどがあげられる。電子線照射量を調整す
る一例をあげると、例えば照射する原反の厚さが５００
μの場合には、２０μ厚さの２５枚の薄いフイルムを緊
密に重ね合わせてほゞ５００μ厚さの試験片とし、これ
に厚さ方向の両側より同量の電子線を照射し、架橋せし
めた試験片を２０μの２５枚のフイルムに分離し、それ
ぞれの架橋度を測定すれば試験片の厚さ方向の架橋度分
布状態をすることができる。この結果から原反の厚さと
電子線照射による架橋度との関係を知ることができる。
上記の電子線照射は、窒素、アルゴン、ヘリウムその他
の不活性ガスの雰囲気で行うことが好ましい。空気の存
在下で電子照射を行うこともできるが、得られるフイル
ムの透明性の改善が十分ではない。上述した架橋剤を配
合したポリエチレンの多層共押出しにより架橋する方法
としては、例えばポリエチレンに有機過酸化物などの架
橋剤を配合（帯電防止剤を含有せず）したものを、シー
ト状原反においては厚さ方向の両側外層とし、チューブ
状原反においては厚さ方向の内外層とし、有機過酸化物
を配合しないか、または前記の最低架橋度以下となるよ
うに有機過酸化物を配合（帯電防止剤を含有）したもの
を原反厚さ方向の中間層となるようにし、架橋度が内側
に段階的に低下するような３層以上の多層共押出機に供
給し、樹脂の融点以上の温度で架橋共押出する方法があ
げられる。Next, in the present invention, a sheet-shaped raw material or a tube-shaped raw material in which the intermediate layer contains an antistatic agent but both surface layers do not contain an antistatic agent It is necessary to perform crosslinking from both sides so that the degree of crosslinking decreases in the thickness direction of the material. Examples of the method for performing such cross-linking include a method of irradiating electron beams from both sides of the raw fabric, or a method of multi-layer coextrusion of a polyethylene resin containing a cross-linking agent (as described above for the antistatic agent). can give. The degree of cross-linking is represented by a gel fraction. In order to achieve the object of the present invention, the gel fraction having the minimum degree of cross-linking in the above-mentioned raw material cross-linking structure is 0 to less than 5%, and both cross-links are cross-linked. 5% gel fraction on the surface
Above all, the range of 20 to 70% is particularly preferable.
When the gel fraction with the minimum degree of cross-linking is 0% and the cross-linked layer / non-cross-linked layer / cross-linked layer is formed in the thickness direction of the raw fabric, the composition ratio of each layer is the non-cross-linked layer: each cross-linked layer on both sides = It is desirable to be in the range of 1: 0.1 to 10, and it is particularly preferable that the cross-linking layers on both sides have the same degree of cross-linking. When the cross-linking is not carried out so that the cross-linking degree decreases in the middle direction in the thickness direction of the raw fabric, especially when the gel fraction having the minimum cross-linking degree exceeds 5%, the subsequent stretching process is performed. It is not uniformly performed, and transparency is improved, but it is difficult to obtain a film having improved moisture resistance. In addition, the degree of crosslinking of each crosslinked surface layer on both sides,
When the gel fraction is less than 20%, the stretching process is not performed uniformly, and it is difficult to improve the transparency and moisture resistance of the film. On the other hand, when the gel fraction exceeds 70%, the film is liable to be broken during the stretching process and it is difficult to smoothly stretch the film. Furthermore, when cross-linking is uniformly performed on all layers in the thickness direction of the raw fabric, the stretching process is performed uniformly and transparency is improved but moisture resistance is not improved. When the film is cross-linked on only one side, the film is easily broken during stretching, and when the entire film is cross-linked so that the degree of cross-linking decreases from one side in the thickness direction of the original film, the moisture resistance and transparency of the resulting film are improved. Are not sufficient and both are not preferable. In addition, the above-mentioned gel fraction shows the insoluble portion obtained by extracting the sample with boiling p-xylene. The method of irradiating the electron beam varies depending on the thickness of the material, the type of resin, the molecular weight, and the molecular weight distribution, but the electron beam irradiation amount is usually 1 to 50 megarads (Mrad), preferably 5 to 20 megarads. do it. Irradiation may be performed simultaneously on the front and back sides or inside and outside of the original fabric, or may be divided into the front and back sides or inside and outside, and may be performed several times. It is particularly preferable that the irradiation dose is the same on the front and back or inside and outside. Further, the adjustment of the electron beam transmissivity includes adjustment of the applied voltage with respect to the original thickness, masking with a shield plate, and the like. As an example of adjusting the electron beam irradiation amount, for example, the thickness of the material to be irradiated is 500
In the case of μ, 25 thin films with a thickness of 20μ are closely overlapped to form a test piece with a thickness of about 500μ, which is irradiated with the same amount of electron beams from both sides in the thickness direction to crosslink. By separating the test piece into 25 films of 20 μm and measuring the degree of crosslinking of each, the distribution of the degree of crosslinking in the thickness direction of the test piece can be obtained. From this result, it is possible to know the relationship between the thickness of the material and the degree of crosslinking by electron beam irradiation.
The above electron beam irradiation is preferably performed in an atmosphere of nitrogen, argon, helium or other inert gas. The electron irradiation can be performed in the presence of air, but the transparency of the obtained film is not sufficiently improved. As a method for crosslinking by multi-layer coextrusion of polyethylene containing the above-mentioned crosslinking agent, for example, polyethylene containing a crosslinking agent such as an organic peroxide (without an antistatic agent) is used in a sheet-shaped raw fabric. Is the outer layers on both sides in the thickness direction, and in the tube-shaped raw material is the inner and outer layers in the thickness direction, and no organic peroxide is blended, or an organic peroxide is blended so that the degree of crosslinking is not more than the above-mentioned minimum crosslinking degree ( (Containing an antistatic agent) is fed to a multi-layer co-extruder with three or more layers so that the degree of cross-linking gradually decreases inward so as to form an intermediate layer in the thickness direction of the original fabric, Examples of the method include cross-linking coextrusion at the temperature of.
【００１１】本発明では、このようにして、電子線照射
などにより効率の良い架橋を行わせ、コア層にのみ帯電
防止剤を入れスキン層には帯電防止剤を入れずに、帯電
防止剤の電子線による分解を防ぎ、その後、一軸あるい
は二軸延伸し、好ましくは、コロナ放電処理および／ま
たはエ−ジング処理（例えば３０〜５０℃での熱処理）
を行うことにより、コア層の帯電防止剤のフィルム表面
への移行を促進させ、全層へ帯電防止剤を入れた場合と
同様、もしくはそれ以上の帯電防止性能を発現させるよ
うにする。延伸は、架橋された原反を加熱し、通常のロ
−ル法、テンタ−法、チュ−ブラ−法もしくは圧延法ま
たはこれらの方法の組合わせによって所定の倍率で一軸
または二軸方向に延伸する方法を採用すればよい。二軸
延伸は、同時または逐次延伸のどちらでも良い。延伸温
度はポリエチレン系樹脂の軟化点以上、特に軟化点から
結晶融点までの範囲が好ましい。また、延伸倍率は、一
方向または縦および横の両方に３倍以上、好ましくは４
倍以上で行う事が望ましい。二軸延伸では、例えば、一
方向に１．１倍、それに直交する方向に６倍以上のアン
バランス延伸であってもよい。In the present invention, in this way, efficient crosslinking is performed by electron beam irradiation or the like, the antistatic agent is added only to the core layer, and the antistatic agent is not added to the skin layer. Prevents decomposition by an electron beam, and then uniaxially or biaxially stretches, preferably corona discharge treatment and / or aging treatment (for example, heat treatment at 30 to 50 ° C.)
By carrying out, the migration of the antistatic agent of the core layer to the film surface is promoted, and the antistatic performance equivalent to or more than the case where the antistatic agent is added to all layers is exhibited. Stretching is carried out by heating a crosslinked raw fabric and stretching it in a uniaxial or biaxial direction at a predetermined magnification by a usual roll method, tenter method, tuber method or rolling method or a combination of these methods. The method of doing may be adopted. The biaxial stretching may be either simultaneous or sequential stretching. The stretching temperature is preferably equal to or higher than the softening point of the polyethylene resin, and particularly preferably in the range from the softening point to the crystal melting point. The stretching ratio is 3 times or more in one direction or both in the longitudinal and lateral directions, preferably 4 times.
It is desirable to do it more than twice. In the biaxial stretching, for example, unbalanced stretching of 1.1 times in one direction and 6 times or more in a direction orthogonal thereto may be performed.
【００１２】[0012]
【実施例】次に、本発明を実施例に基づいて説明する。
なお、実施例における％および部は重量を表わし、試験
方法は次の通りである。
（１）帯電圧減衰率・半減期：フイルム表面に放電（１
０ｋｖ，１Ａ，６０秒）を起こさせ、静電圧計でその帯
電圧が半分になるまでの時間を測定した。フイルルの両
面の測定値を平均値で示した。
（２）ゲル分率；ＡＳＴＭ ２７４５Ａ法EXAMPLES Next, the present invention will be explained based on examples.
In the examples,% and part represent weight, and the test method is as follows. (1) Charge voltage decay rate / half-life: discharge on the film surface (1
(0 kv, 1 A, 60 seconds), and the time until the charged voltage becomes half was measured with a static voltmeter. The measured values on both sides of the film are shown by the average value. (2) Gel fraction; ASTM 2745A method
【００１３】実施例１．高密度ポリエチレン（密度０．
９５７ｇ／ｃｍ3 、ＭＩ：０．８ｇ／１０分、以下ＨＤ
ＰＥという）を二種三層共押しダイにより、厚さ０．６
ｍｍのシ−ト状原反に成形し、このうちコア層のみに１
４％濃度の帯電防止剤マスタ−バッチ（花王社製商品名
エレクトロストリッパ−ＥＡ、アルキルアミンの非イオ
ン系帯電防止剤４％と丸菱油化社製商品名デノン２２２
０、アルキルアミンと多価アルコ−ルの混合物の非イオ
ン系帯電防止剤１０％））を表１に示す量練り込んだ。
ここで樹脂の吐出量を測定し、スキン層、コア層、スキ
ン層の層構成比が１：３：１であることを確認した。こ
のシ−ト状原反に、電子線照射装置（ＥＳＩ社製）を用
い、窒素ガス雰囲気下でそれぞれに１９５ＫＶ−４０ｍ
Ａの条件下で１８メガラッドの電子線を照射した。この
架橋シ−トの照射面およびシ−トの厚さ方向の内部の架
橋度を知るために、上記ＨＤＰＥからなる厚さ２０μｍ
の薄いフィルム３０枚を重ねて厚さ０．６ｍｍの試験片
とし、同一条件で電子線を照射して、各々の薄いフィル
ムの架橋度を調べたところ、照射両面側の薄いフィルム
の架橋度はゲル分率５０％、厚さ方向内部の最低架橋は
ゲル分率０％であった。また架橋層および未架橋層の厚
さの構成比は、架橋層：未架橋層：架橋層＝１：２：１
であった。この架橋シ−トを温度１３０℃で、縦方向に
１．２倍、横方向７．７倍に延伸して厚さ６０μｍの二
軸延伸ＨＤＰＥフィルムを得た。このフィルムにコロナ
放電処理を行い、フィルムの濡れ指数４５ｄｙｎ／ｃｍ
のものを得た。このフィルムに４０℃で２４時間エ−ジ
ングを行い、さらに２３℃、湿度５０％の恒温室で１時
間放置した後、帯電防止性能を測定した。結果を表１に
示す。Embodiment 1. High-density polyethylene (density 0.
957 g / cm 3 , MI: 0.8 g / 10 minutes, HD below
0.6) with a two-kind three-layer co-press die
mm sheet-shaped original fabric, of which only 1 is applied to the core layer
Antistatic agent master batch with a concentration of 4% (trade name: Electrostriper-EA manufactured by Kao Co., nonionic antistatic agent of alkylamine: 4%, and Denon 222, trade name, manufactured by Marubishi Yuka Co., Ltd.)
0, a nonionic antistatic agent (10%) of a mixture of alkylamine and polyhydric alcohol) was kneaded in the amount shown in Table 1.
Here, the discharge amount of the resin was measured and it was confirmed that the layer constitution ratio of the skin layer, the core layer and the skin layer was 1: 3: 1. An electron beam irradiator (manufactured by ESI) was used for each of the sheet-shaped sheets, and each sheet was 195 KV-40 m under a nitrogen gas atmosphere.
Under the conditions of A, the electron beam of 18 megarad was irradiated. In order to know the irradiation degree of the crosslinked sheet and the degree of crosslinking inside the sheet in the thickness direction, the thickness of the HDPE is 20 μm.
Of 30 thin films were stacked to form a test piece having a thickness of 0.6 mm, and the degree of crosslinking of each thin film was examined by irradiating it with an electron beam under the same conditions. The gel fraction was 50%, and the minimum cross-linking in the thickness direction was 0%. The composition ratio of the thicknesses of the crosslinked layer and the uncrosslinked layer is as follows: crosslinked layer: uncrosslinked layer: crosslinked layer = 1: 2: 1
Met. The crosslinked sheet was stretched 1.2 times in the longitudinal direction and 7.7 times in the transverse direction at a temperature of 130 ° C. to obtain a biaxially stretched HDPE film having a thickness of 60 μm. Corona discharge treatment is applied to this film to obtain a film wetting index of 45 dyn / cm.
Got one. The film was aged at 40 ° C. for 24 hours, and allowed to stand in a thermostatic chamber at 23 ° C. and a humidity of 50% for 1 hour, and then the antistatic performance was measured. The results are shown in Table 1.
【００１４】実施例２．実施例１で使用の帯電防止剤マ
スタ−バッチを表１に示す量練り込んだ以外は、実施例
１と同様にして、フィルムを得、帯電防止性能を測定し
た。結果を表１に示す。Example 2. A film was obtained and antistatic performance was measured in the same manner as in Example 1 except that the antistatic agent master batch used in Example 1 was kneaded in the amounts shown in Table 1. The results are shown in Table 1.
【００１５】実施例３．実施例１で使用の帯電防止剤マ
スタ−バッチをを表１に示す量練り込んだ以外は，実施
例１と同様にして、フィルムを得、帯電防止性能を測定
した。結果を表１に示す。Example 3. A film was obtained and the antistatic performance was measured in the same manner as in Example 1 except that the antistatic agent master batch used in Example 1 was kneaded in the amounts shown in Table 1. The results are shown in Table 1.
【００１６】比較例１〜３．コア層には帯電防止剤マス
タ−バッチを練り込みせず、スキン層には帯電防止剤マ
スタ−バッチを表１に示す量練り込んだ以外は，実施例
１と同様にして、フィルムを得、帯電防止性能を測定し
た。結果を表１に示す。Comparative Examples 1-3. A film was obtained in the same manner as in Example 1 except that the antistatic agent master batch was not kneaded into the core layer and the antistatic agent master batch was kneaded into the skin layer in the amounts shown in Table 1. The antistatic performance was measured. The results are shown in Table 1.
【００１７】比較例４．コア層のみならず、スキン層に
も帯電防止剤マスタ−バッチを表１に示す量練り込んだ
以外は，実施例１と同様にして、フィルムを得、帯電防
止性能を測定した。結果を表１に示す。Comparative Example 4. A film was obtained and the antistatic performance was measured in the same manner as in Example 1 except that the antistatic agent master batch was kneaded in the skin layer as well as the core layer in the amounts shown in Table 1. The results are shown in Table 1.
【００１８】実施例４．コア層のみに帯電防止剤マスタ
−バッチを表２に示す量練り込み、また、縦方向に５
倍、横方向に７．８倍に延伸して厚さ１５μｍの二軸延
伸ＨＤＰＥフィルムとした以外は、実施例１と同様にし
て、フィルムを得、帯電防止性能を測定した。結果を表
２に示す。Example 4. The antistatic agent master-batch was kneaded in the core layer only in the amount shown in Table 2, and was mixed in the longitudinal direction with 5
The film was obtained and the antistatic performance was measured in the same manner as in Example 1 except that a biaxially stretched HDPE film having a thickness of 15 μm was obtained by stretching the film twice and 7.8 times in the transverse direction. The results are shown in Table 2.
【００１９】比較例５．コア層のみならず、スキン層に
も帯電防止剤マスタ−バッチを表２に示す量練り込みし
た以外は、実施例４と同様にして、フィルムを得、帯電
防止性能を測定した。結果を表２に示す。Comparative Example 5. A film was obtained and antistatic performance was measured in the same manner as in Example 4 except that the antistatic agent master batch was kneaded not only in the core layer but also in the skin layer as shown in Table 2. The results are shown in Table 2.
【００２０】[0020]
【表１】 表１ 帯電防止性能評価結果 原反の 架橋延伸フイルムの 帯 電 防 止 剤 濃 度 帯電圧減衰率・半減期 スキン層 コア層 全 層 ［wt％］ ［wt％］［wt％］ ［ｓｅｃ］ 実施例−１ − 0.35 0.21 43 実施例−２ − 0.53 0.32 11 実施例−３ − 0.70 0.42 6 比較例−１ 0.49 − 0.20 400 以上 比較例−２ 0.73 − 0.30 25 比較例−３ 1.05 − 0.42 10 比較例−４ 0.35 0.35 0.35 16 [Table 1] Table 1 Antistatic performance evaluation results Of crosslinked stretched film Antistatic agent Concentration Concentration of voltage and attenuation rate / half-life Skin layer Core layer All layers [Wt%] [wt%] [wt%] [sec] Example-1-0.35 0.21 43 Example-2-0.53 0.32 11 Example-3-0.70 0.42 6 Comparative Example-1 0.49-0.20 400 that's all Comparative Example-2 0.73-0.30 25 Comparative Example-3 1.05-0.42 10 Comparative Example-4 0.35 0.35 0.35 16
【００２１】[0021]
【表２】 表２ 帯電防止性能評価結果 原反の 架橋延伸フイルムの 帯 電 防 止 剤 濃 度 帯電圧減衰率・半減期 スキン層 コア層 全 層 ［wt％］ ［wt％］［wt％］ ［ｓｅｃ］ 実施例−４ − 2.34 1.40 ３２ 比較例−５ 1.40 1.40 1.40 ９０[Table 2] Table 2 Antistatic performance evaluation results Of crosslinked stretched film Antistatic agent Concentration Concentration of voltage and attenuation rate / half-life Skin layer Core layer All layers [Wt%] [wt%] [wt%] [sec] Example-4-2.34 1.40 32 Comparative Example-5 1.40 1.40 1.40 90
【００２２】[0022]
【発明の効果】本発明によれば、架橋度がフイルムの厚
さ方向に低下したポリエチレン架橋延伸フイルムの透明
度（ヘイズ値）が高く、かつ、防湿性に優れているなど
種々の優れた特性を生かしつつ、その帯電防止性能を最
大限に発揮することができる技術を提供することができ
た。すなわち、均一に全体に帯電防止剤を配した当該フ
イルム原反に電子線を照射するなどして、架橋度がフィ
ルムの厚さ方向において、内側に低下したポリエチレン
延伸フィルムを成形すると、電子線がフィルム表面付近
の帯電防止剤を分解するために、添加した帯電防止剤の
うち表面付近に存在するものの多くは無駄になり、この
ため、十分な帯電防止効果を発現させるためには、必要
以上の帯電防止剤を添加することなどにより対処せざる
を得ず、この必要以上の帯電防止剤の添加はコスト的に
も問題があり、しかも、照射された電子線のある程度
は、この帯電防止剤の分解に消費されるため、効率の良
い架橋が行われていず、電子線の架橋効率の低下を招い
ていたが、本発明によれば、過剰な帯電防止剤を使用す
る必要がなくなり、コストの削減が可能になり、さらに
照射電子線を効率良く、ポリエチレン樹脂の架橋に供し
させることに成功した。According to the present invention, a polyethylene crosslinked stretched film having a degree of crosslinking reduced in the thickness direction of the film has high transparency (haze value) and excellent moisture resistance. It was possible to provide a technology that can maximize its antistatic performance while making the most of it. That is, by irradiating the original film of the film having the antistatic agent evenly distributed with an electron beam, when a polyethylene stretched film having a degree of cross-linking lowered inward is formed, the electron beam becomes In order to decompose the antistatic agent near the film surface, many of the added antistatic agents existing near the surface are wasted. Therefore, in order to exert a sufficient antistatic effect, more than necessary is required. There is no choice but to deal with it by adding an antistatic agent, and the addition of more antistatic agent than this is problematic in terms of cost. Since it was consumed for decomposition, efficient cross-linking was not performed, leading to a decrease in electron beam cross-linking efficiency.However, according to the present invention, it is not necessary to use an excessive antistatic agent, and the cost is reduced. Allows reduction of further efficiently electron beam irradiation, and succeeded in giving subjected to cross-linking of the polyethylene resin.
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Claims (2)
両表層には帯電防止剤を含有していないポリエチレンよ
りなるシ−ト状原反またはチュ−ブ状原反を、少なくと
も三層の共押出しにより成形後、当該原反の厚さ方向に
おいて中方向に架橋度が低下するように架橋させた後、
少なくとも一方向に延伸を行なうことを特徴とする帯電
防止性ポリエチレン架橋延伸フィルムの製法。1. The intermediate layer contains an antistatic agent,
After forming a sheet-shaped raw material or a tube-shaped raw material made of polyethylene containing no antistatic agent on both surface layers by co-extrusion of at least three layers, the sheet-shaped raw material or the tube-shaped raw material is oriented in the middle direction in the thickness direction of the raw material. After crosslinking to reduce the degree of crosslinking to
A method for producing an antistatic polyethylene crosslinked stretched film, which comprises stretching in at least one direction.
も一方向に延伸を行なった後、コロナ放電処理および／
またはエ−ジング処理を施すことを特徴とする、請求項
１に記載の帯電防止性ポリエチレン架橋延伸フィルムの
製法。2. The production method according to claim 1, wherein after stretching in at least one direction, corona discharge treatment and / or
Alternatively, an aging treatment is performed, and the method for producing an antistatic polyethylene crosslinked stretched film according to claim 1.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP3211383A JPH0531803A (en) | 1991-07-30 | 1991-07-30 | Manufacture of antistatic polyethylene crosslinking oriented film |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP3211383A JPH0531803A (en) | 1991-07-30 | 1991-07-30 | Manufacture of antistatic polyethylene crosslinking oriented film |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| JPH0531803A true JPH0531803A (en) | 1993-02-09 |
Family
ID=16605058
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP3211383A Pending JPH0531803A (en) | 1991-07-30 | 1991-07-30 | Manufacture of antistatic polyethylene crosslinking oriented film |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPH0531803A (en) |
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|---|---|---|---|---|
| EP0874033A1 (en) * | 1997-01-06 | 1998-10-28 | Dsm N.V. | Process for improving the adhesion between a polymer film and a polymer matrix |
| EP0896992A1 (en) * | 1997-08-11 | 1999-02-17 | Dsm N.V. | Process for adhering two polymer materials using a plasma treatment |
| JP2006303234A (en) * | 2005-04-21 | 2006-11-02 | Sekisui Film Kk | Adhesive sheet for solar cell |
| JP2006303233A (en) * | 2005-04-21 | 2006-11-02 | Sekisui Chem Co Ltd | Adhesive sheet for solar cell |
| WO2007068792A1 (en) * | 2005-12-14 | 2007-06-21 | Conenor Oy | Method for making a composite product, and a composite product |
| JP2008221839A (en) * | 2007-02-15 | 2008-09-25 | Jsp Corp | Antistatic multilayer sheet and antistatic thermoformed article |
| JP2010036392A (en) * | 2008-08-01 | 2010-02-18 | Toppan Forms Co Ltd | Synthetic resin multilayer film and bag using this film |
-
1991
- 1991-07-30 JP JP3211383A patent/JPH0531803A/en active Pending
Cited By (9)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| EP0874033A1 (en) * | 1997-01-06 | 1998-10-28 | Dsm N.V. | Process for improving the adhesion between a polymer film and a polymer matrix |
| EP0896992A1 (en) * | 1997-08-11 | 1999-02-17 | Dsm N.V. | Process for adhering two polymer materials using a plasma treatment |
| JP2006303234A (en) * | 2005-04-21 | 2006-11-02 | Sekisui Film Kk | Adhesive sheet for solar cell |
| JP2006303233A (en) * | 2005-04-21 | 2006-11-02 | Sekisui Chem Co Ltd | Adhesive sheet for solar cell |
| JP4662805B2 (en) * | 2005-04-21 | 2011-03-30 | 積水化学工業株式会社 | Manufacturing method of adhesive sheet for solar cell |
| JP4662806B2 (en) * | 2005-04-21 | 2011-03-30 | 積水フイルム株式会社 | Manufacturing method of adhesive sheet for solar cell |
| WO2007068792A1 (en) * | 2005-12-14 | 2007-06-21 | Conenor Oy | Method for making a composite product, and a composite product |
| JP2008221839A (en) * | 2007-02-15 | 2008-09-25 | Jsp Corp | Antistatic multilayer sheet and antistatic thermoformed article |
| JP2010036392A (en) * | 2008-08-01 | 2010-02-18 | Toppan Forms Co Ltd | Synthetic resin multilayer film and bag using this film |
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