JPH0450888B2 - - Google Patents
Info
- Publication number
- JPH0450888B2 JPH0450888B2 JP58234021A JP23402183A JPH0450888B2 JP H0450888 B2 JPH0450888 B2 JP H0450888B2 JP 58234021 A JP58234021 A JP 58234021A JP 23402183 A JP23402183 A JP 23402183A JP H0450888 B2 JPH0450888 B2 JP H0450888B2
- Authority
- JP
- Japan
- Prior art keywords
- mandrel
- diameter
- film
- cylindrical
- annular slit
- 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.)
- Expired - Lifetime
Links
- 238000000034 method Methods 0.000 claims description 18
- 238000000465 moulding Methods 0.000 claims description 15
- 229920005672 polyolefin resin Polymers 0.000 claims description 9
- 239000000155 melt Substances 0.000 claims description 7
- 229920001903 high density polyethylene Polymers 0.000 claims description 3
- 239000004700 high-density polyethylene Substances 0.000 claims description 3
- 239000002470 thermal conductor Substances 0.000 claims 1
- 102100027340 Slit homolog 2 protein Human genes 0.000 description 7
- 101710133576 Slit homolog 2 protein Proteins 0.000 description 7
- XEEYBQQBJWHFJM-UHFFFAOYSA-N Iron Chemical compound [Fe] XEEYBQQBJWHFJM-UHFFFAOYSA-N 0.000 description 6
- 229920003002 synthetic resin Polymers 0.000 description 5
- 239000000057 synthetic resin Substances 0.000 description 5
- 230000000052 comparative effect Effects 0.000 description 4
- 229910052742 iron Inorganic materials 0.000 description 3
- 239000000463 material Substances 0.000 description 3
- 230000006641 stabilisation Effects 0.000 description 3
- 238000011105 stabilization Methods 0.000 description 3
- 229920003355 Novatec® Polymers 0.000 description 2
- XAGFODPZIPBFFR-UHFFFAOYSA-N aluminium Chemical compound [Al] XAGFODPZIPBFFR-UHFFFAOYSA-N 0.000 description 2
- 229910052782 aluminium Inorganic materials 0.000 description 2
- RLAWWYSOJDYHDC-BZSNNMDCSA-N lisinopril Chemical compound C([C@H](N[C@@H](CCCCN)C(=O)N1[C@@H](CCC1)C(O)=O)C(O)=O)CC1=CC=CC=C1 RLAWWYSOJDYHDC-BZSNNMDCSA-N 0.000 description 2
- -1 polyethylene Polymers 0.000 description 2
- 239000000126 substance Substances 0.000 description 2
- 229910001369 Brass Inorganic materials 0.000 description 1
- RYGMFSIKBFXOCR-UHFFFAOYSA-N Copper Chemical compound [Cu] RYGMFSIKBFXOCR-UHFFFAOYSA-N 0.000 description 1
- 239000004698 Polyethylene Substances 0.000 description 1
- 238000007664 blowing Methods 0.000 description 1
- 239000010951 brass Substances 0.000 description 1
- 230000008602 contraction Effects 0.000 description 1
- 229920001577 copolymer Polymers 0.000 description 1
- 239000010949 copper Substances 0.000 description 1
- 229910052802 copper Inorganic materials 0.000 description 1
- 230000002950 deficient Effects 0.000 description 1
- 229910003460 diamond Inorganic materials 0.000 description 1
- 239000010432 diamond Substances 0.000 description 1
- 230000000694 effects Effects 0.000 description 1
- 239000005038 ethylene vinyl acetate Substances 0.000 description 1
- 238000011156 evaluation Methods 0.000 description 1
- 238000001125 extrusion Methods 0.000 description 1
- 229920000092 linear low density polyethylene Polymers 0.000 description 1
- 239000004707 linear low-density polyethylene Substances 0.000 description 1
- 238000000691 measurement method Methods 0.000 description 1
- 238000004806 packaging method and process Methods 0.000 description 1
- 230000000149 penetrating effect Effects 0.000 description 1
- 229920001200 poly(ethylene-vinyl acetate) Polymers 0.000 description 1
- 229920001748 polybutylene Polymers 0.000 description 1
- 229920000573 polyethylene Polymers 0.000 description 1
- 239000011148 porous material Substances 0.000 description 1
- 229920005989 resin Polymers 0.000 description 1
- 239000011347 resin Substances 0.000 description 1
- 238000007711 solidification Methods 0.000 description 1
- 230000008023 solidification Effects 0.000 description 1
- 229910001220 stainless steel Inorganic materials 0.000 description 1
- 239000010935 stainless steel Substances 0.000 description 1
- 229920001169 thermoplastic Polymers 0.000 description 1
- 239000004416 thermosoftening plastic Substances 0.000 description 1
Classifications
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
- B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
- B29C48/00—Extrusion moulding, i.e. expressing the moulding material through a die or nozzle which imparts the desired form; Apparatus therefor
- B29C48/25—Component parts, details or accessories; Auxiliary operations
- B29C48/88—Thermal treatment of the stream of extruded material, e.g. cooling
- B29C48/90—Thermal treatment of the stream of extruded material, e.g. cooling with calibration or sizing, i.e. combined with fixing or setting of the final dimensions of the extruded article
- B29C48/901—Thermal treatment of the stream of extruded material, e.g. cooling with calibration or sizing, i.e. combined with fixing or setting of the final dimensions of the extruded article of hollow bodies
- B29C48/902—Thermal treatment of the stream of extruded material, e.g. cooling with calibration or sizing, i.e. combined with fixing or setting of the final dimensions of the extruded article of hollow bodies internally
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
- B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
- B29C48/00—Extrusion moulding, i.e. expressing the moulding material through a die or nozzle which imparts the desired form; Apparatus therefor
- B29C48/03—Extrusion moulding, i.e. expressing the moulding material through a die or nozzle which imparts the desired form; Apparatus therefor characterised by the shape of the extruded material at extrusion
- B29C48/09—Articles with cross-sections having partially or fully enclosed cavities, e.g. pipes or channels
- B29C48/10—Articles with cross-sections having partially or fully enclosed cavities, e.g. pipes or channels flexible, e.g. blown foils
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
- B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
- B29C48/00—Extrusion moulding, i.e. expressing the moulding material through a die or nozzle which imparts the desired form; Apparatus therefor
- B29C48/25—Component parts, details or accessories; Auxiliary operations
- B29C48/88—Thermal treatment of the stream of extruded material, e.g. cooling
- B29C48/911—Cooling
- B29C48/9115—Cooling of hollow articles
- B29C48/912—Cooling of hollow articles of tubular films
- B29C48/9125—Cooling of hollow articles of tubular films internally
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
- B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
- B29C48/00—Extrusion moulding, i.e. expressing the moulding material through a die or nozzle which imparts the desired form; Apparatus therefor
- B29C48/001—Combinations of extrusion moulding with other shaping operations
- B29C48/0018—Combinations of extrusion moulding with other shaping operations combined with shaping by orienting, stretching or shrinking, e.g. film blowing
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
- B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
- B29C48/00—Extrusion moulding, i.e. expressing the moulding material through a die or nozzle which imparts the desired form; Apparatus therefor
- B29C48/001—Combinations of extrusion moulding with other shaping operations
- B29C48/0019—Combinations of extrusion moulding with other shaping operations combined with shaping by flattening, folding or bending
Landscapes
- Engineering & Computer Science (AREA)
- Mechanical Engineering (AREA)
- Physics & Mathematics (AREA)
- Thermal Sciences (AREA)
- Shaping By String And By Release Of Stress In Plastics And The Like (AREA)
- Extrusion Moulding Of Plastics Or The Like (AREA)
Description
【発明の詳細な説明】
本発明はインフレーシヨンフイルム成形方法に
関する。詳しくは、強度バランスの良い薄肉の合
成樹脂フイルムを、高能率に、かつ安定して成形
するインフレーシヨンフイルム成形方法に関す
る。
近年、合成樹脂フイルムを用いた包装袋等にお
いては、材料の節約等の上から薄肉化が検討され
ている。
インフレーシヨンフイルムを成形するに際し、
フイルムを薄肉化するには、ドラフト率を大きく
又は／及びブロー比を大きくする方法がある。
しかしながら、インフレーシヨン成形は、筒状
に押し出した合成樹脂の内部に空気を吹込み膨張
させるものである関係上、膨まされたバブルは不
安定な状態にあり、特に薄肉化のためにドラフト
率を大きく又は／及びブロー比を大きくして成形
しようとするとバブルの揺動や破断が起り安定し
た成形は大変に難かしい。
特に溶融張力の大きい合成樹脂を用いた場合、
ダイの環状スリツトから押出された筒状フイルム
は、所謂ネツクインを起し、一旦環状スリツトの
径よりも小さい径にまで細くなり、次いで膨張す
ることとなるので、バブルを支持する部分が実質
的に小さくなり、不安定となる傾向が強い。
本発明者等は、溶融張力の大きい熱可塑性合成
樹脂を安定して高速で成形する方法に関して種々
検討を行なつた結果、特定の溶融張力のポリオレ
フイン系樹脂を用い、ダイスに特定構造のマンド
レルを取付けて成形を行なうことにより、極めて
安定して、厚み精度の良好なフイルムが高能率に
得られることを見出し、本発明を完成するに至つ
た。
すなわち、本発明の要旨は溶融張力３ｇ以上の
ポリオレフイン樹脂をインフレーシヨン成形する
に当り、環状スリツトを有するダイからポリオレ
フイン樹脂を筒状に押し出し、押し出された溶融
状態にある筒状フイルムを、環状スリツトの径以
上で環状スリツトの径の1.3倍以下の径を有する
下部から上部まで実質的に同径で、且つ内外を貫
通する多数の貫通孔を有する筒状マンドレルに添
わせて移動せしめ、次いで膨張させながら引取る
ことを特徴とするインフレーシヨンフイルム成形
方法に存する。
以下本発明の方法の一例につき図面を用いて説
明する。
第１図は本発明の方法に用いるインフレーシヨ
ンフイルム成形装置の一例を示す説明図である。
図中１はダイ、２は環状スリツト、３はマンド
レル、４は貫通孔、５は空気導入孔、６，７は空
気吹出口、８は筒状フイルム、９はエアーリン
グ、１０は開閉弁をそれぞれ示す。
本発明方法に使用されるポリオレフイン樹脂と
してはポリエチレン、ポリプロリレン、エチレン
−プロピレン共重合体、ポリブテン−１、エチレ
ン酢酸ビニル共重合体、線状低密度ポリエチレン
等が挙げられ、これらの中でも溶融張力が３ｇ以
上のものが用いられる。
溶融張力は、樹脂をJISK6760のメルトインデ
ツクス測定法において使用するノズルから160℃、
1.22ｍ／minで押し出し、1.52ｍ／minの速度で
引張つたときのノズルから25cm離れた位置で測定
した張力（ｇ）である。
溶融張力が３ｇ未満のポリオレフイン樹脂を使
用した場合、成形は可能であるが、得られたフイ
ルムの強度、特に引裂強度や衝撃強度等が満足な
ものが得られない。
上記した溶融張力３ｇ以上のポリオレフイン樹
脂の中でも密度0.935ｇ／cm3以上、メルトインデ
ツクス１ｇ／10分以下の高密度ポリエチレンが、
フイルムのタテ・ヨコ配向バランスをとりやす
く、かつ到達強度の高いフイルムが得られ本発明
の成形方法に好適に使用し得る。
ダイ１の環状スリツト２から押し出された筒状
フイルム８は、その上部に設けられたマンドレル
３に沿つて上昇し、筒状体内部に封入された空気
により膨張されて引取られる。
マンドレル３は、その径が環状スリツト２の径
以上で環状スリツト２の径の1.3倍以下で下部か
ら上部まで実質的に同径とされている。また、マ
ンドレル３の高さは環状スリツト２から押出され
た筒状フイルム８が、所謂ネツクインを起す位
置、すなわち、筒状フイルム８の径が自然収縮に
より環状スリツト２の径よりも小さくなる位置以
上の高さが必要であり、その高さの上限について
は特に制限を設けるものではないが、作業性の面
から筒状フイルム８の固化位置（フロストライ
ン）までの高さであるのが好ましい。
このような径及び高さのマンドレル３に沿つて
筒状フイルム８は移動するため、筒状フイルム８
の引取速度を速くしても筒状フイルム８の径が環
状スリツト２の径より細くなつてバブルが不安定
になつたり、一旦細くなつた筒状フイルムが膨張
する際に径の変化が大きすぎて破裂したりするこ
とがない。
マンドレル３の表面（側面）には、内外を貫通
する多数の貫通孔４が設けられている。貫通孔４
はその孔径が通常0.5〜20mm、好ましくは１〜５
mmの範囲の長径又は短径を有するものであつて、
マンドレル３の全表面積（側面の面積）に対する
貫通孔４の全開孔面積の割合、すなわち開孔率は
通常10〜70％、好ましくは20〜40％の範囲であ
る。該貫通孔４の形状としては、円形、楕円形、
角形、菱形、十字形又はそれらの組合せ等が挙げ
られ、またその孔の配列としては千鳥型又は平行
型等が挙げられる。該貫通孔４の形状及び配列の
例を第２図〜第７図に示す。
マンドレル３の表面は筒状フイルム８の立上げ
時のバブルの安定化を良好とするため熱伝導率
10kcal／ｍ・hr・℃を超える材質のものを用いる
のが良く、具体的には例えばアルニミウム、鉄、
銅、ステンレス、黄銅等が挙げられる。中でも加
工性、熱伝導率、耐久性の点から鉄が好適に使用
し得る。該マンドレルはその肉厚が薄いもの程筒
状フイルムの立上げ時のバブルの安定化が早くな
るので好ましいが、あまり肉厚が薄くなりすぎる
とマンドレルの強度及び耐久性の点で問題とな
る。それ故、マンドレル３の肉厚は加工性、強度
及び耐久性の点から通常0.5〜５mm、好ましくは
0.5〜２mmの範囲が適当である。
マンドレル３の表面において、貫通孔４を有さ
ない部分の表面はあまり平滑であると溶融状態に
ある筒状フイルム８が粘着してしまい筒状フイル
ム８が破断する原因となるので、その表面に、
0.01mm以上の凹凸を形成するのが良い。
マンドレル３の表面に上記した貫通孔４を設け
たり凹凸を設けたりすることにより、筒状フイル
ム８の立上げ時のバブルの安定化が著しく改善さ
れること以外に、溶融状態にある筒状フイルム８
とマンドレル３との間に空気層が形成され引取抵
抗を低下させる効果もある。
また、マンドレル３はダイ１からあまり離して
設けると、ダイ１から押し出された筒状フイルム
８が一旦細くなつて再び膨らまされるような形と
なる場合があり、破断の原因となるのでダイ１の
表面からマンドレル３の実質的に同径の部分が始
まる位置までの距離が環状スリツト２の径の1/10
以上１以下であるのが望ましい。
本発明の方法によつてインフレーシヨン成形を
行なう場合、ブロー比は２以上程度、ドラフト率
（引取速度／押出速度）は４以上として成形する
のが、成形の安定性、製品フイルムの強度バラン
ス等の上から望ましい。
以下、実施例により本発明の方法を更に説明す
るが本発明はその要旨を越えない限り以下の実施
例に限定されるものではない。
実施例 １〜３
高密度ポリエチレン｛三菱化成工業(株)製、ノバ
テツクR4000F、メルトインデツクス：0.05ｇ／
10分、密度：0.954ｇ／cm3、溶融張力：９ｇ｝（ノ
バテツクは三菱化成工業(株)の登録商標）を用い50
mmφの押出機に50mmφの環状スリツトを有するダ
イ及び55mmφのマンドレルを取付けたインフレー
シヨン成形装置により、シリンダー温度200℃、
ダイヘツド温度200℃、ダイ温度200℃の条件下、
インフレーシヨン成形した。
マンドレルは長さ500mm、肉厚１mmの鉄製の中
空円筒体であつて、その側面には第２図に示すよ
うな形状及び配列の２mmφの貫通穴が30％の開孔
率で設けられている。
ダイ表面からマンドレルの実質的に同径の部分
が始まる位置までの距離は16mmとした。バブルの
膨張はダイ面から350mmの位置から始まつた。
ブローアツプ比は3.8の一定とし、引取速度を
24ｍ／分（実施例１）、30ｍ／分（実施例２）、60
ｍ／分（実施例３）とし、夫々25μ、20μ、10μの
厚さのフイルムを得、この際バブルの安定化時
間、バブルの安定性及び得られたフイルムの強度
バランスにより評価を行つた。
バブル安定化時間については溶融状態にある筒
状フイルムをマンドレル表面に接触させてから安
定な状態で製膜が可能となるまでの時間（分）で
表わした。
バブル安定性の評価は目視によりバブルを観察
し、良好、やや不安定、不安定の３段階で評価し
た。
強度バランスについては得られたフイルムを手
で引取方向に引き裂き、切れ目の進む方向が縦方
向か、横方向か、又は斜めかを見、斜めに切れ目
が進むものを強度バランス良好とし、縦又は横方
向に片よるものを不良とした。
結果を第１表に示す。
比較例 １
実施例１のマンドレルを長さ500mmのアルミニ
ウム製の円筒体の表面に深さ0.7mm、幅0.5mmの条
溝をピツチ１mmで互いに交差させて網目状の凹凸
を設けたマンドレルに取り換えたものを用いたこ
と以外は実施例１と同様にしてインフレーシヨン
成形を行ない、評価した。
結果を第１表に示す。
比較例 ２、３
実施例１のマンドレルを35mmφのものと取り換
えたもの（比較例２）、実施例１のマンドレルを
取り外したもの（比較例３）とした装置を用いた
ほかは実施例１と同様にしてインフレーシヨン成
形を行ない、評価した。
結果を第１表に示す。
【表】DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for forming an inflation film. More specifically, the present invention relates to an inflation film molding method for highly efficiently and stably molding a thin synthetic resin film with well-balanced strength. In recent years, packaging bags and the like using synthetic resin films are being considered to be made thinner in order to save on materials. When forming blown film,
One way to make the film thinner is to increase the draft rate and/or blow ratio. However, because inflation molding involves blowing air into the interior of a synthetic resin extruded into a cylindrical shape to inflate it, the inflated bubble is in an unstable state. If molding is attempted with a large blow ratio and/or a large blow ratio, the bubbles will swing or break, making stable molding very difficult. Especially when using synthetic resin with high melt tension,
The cylindrical film extruded from the annular slit of the die undergoes so-called neck-in, and once becomes thinner to a diameter smaller than the diameter of the annular slit, and then expands, so that the part that supports the bubble is substantially reduced. There is a strong tendency to become small and unstable. The present inventors conducted various studies on a method for stably and rapidly molding a thermoplastic synthetic resin with a high melt tension, and found that using a polyolefin resin with a specific melt tension, and using a mandrel with a specific structure in the die. The inventors have discovered that by attaching and forming a film, it is possible to obtain an extremely stable film with good thickness accuracy with high efficiency, and have completed the present invention. That is, the gist of the present invention is that when performing inflation molding of a polyolefin resin having a melt tension of 3 g or more, the polyolefin resin is extruded into a cylindrical shape from a die having an annular slit, and the extruded molten cylindrical film is molded into an annular shape. The mandrel is moved along a cylindrical mandrel which has a diameter greater than or equal to the diameter of the slit and less than or equal to 1.3 times the diameter of the annular slit, and which has substantially the same diameter from the bottom to the top and has a large number of through holes penetrating the inside and outside. The invention resides in a method for forming an inflation film characterized by taking it off while expanding it. An example of the method of the present invention will be described below with reference to the drawings. FIG. 1 is an explanatory view showing an example of an inflation film forming apparatus used in the method of the present invention. In the figure, 1 is a die, 2 is an annular slit, 3 is a mandrel, 4 is a through hole, 5 is an air introduction hole, 6 and 7 are air outlets, 8 is a cylindrical film, 9 is an air ring, and 10 is an on-off valve. Each is shown below. Examples of the polyolefin resin used in the method of the present invention include polyethylene, polyprolylene, ethylene-propylene copolymer, polybutene-1, ethylene-vinyl acetate copolymer, and linear low-density polyethylene, among which melt tension is 3 g. The above are used. The melt tension is measured when the resin is measured at 160℃ from the nozzle used in the JISK6760 melt index measurement method.
This is the tension (g) measured at a position 25 cm away from the nozzle when extruding at a speed of 1.22 m/min and pulling at a speed of 1.52 m/min. When a polyolefin resin having a melt tension of less than 3 g is used, molding is possible, but the resulting film cannot have satisfactory strength, particularly tear strength and impact strength. Among the above-mentioned polyolefin resins with a melt tension of 3 g or more, high-density polyethylene with a density of 0.935 g/cm 3 or more and a melt index of 1 g/10 min or less is
It is easy to balance the vertical and horizontal orientation of the film, and a film with high ultimate strength can be obtained, and can be suitably used in the molding method of the present invention. The cylindrical film 8 extruded from the annular slit 2 of the die 1 rises along the mandrel 3 provided above, is expanded by the air sealed inside the cylindrical body, and is taken off. The diameter of the mandrel 3 is greater than or equal to the diameter of the annular slit 2 and less than 1.3 times the diameter of the annular slit 2, and is substantially the same diameter from the bottom to the top. Further, the height of the mandrel 3 is set to be at least a position where the cylindrical film 8 extruded from the annular slit 2 causes so-called neck-in, that is, a position where the diameter of the cylindrical film 8 becomes smaller than the diameter of the annular slit 2 due to natural contraction. Although there is no particular restriction on the upper limit of the height, from the viewpoint of workability it is preferably the height up to the solidification position (frost line) of the cylindrical film 8. Since the cylindrical film 8 moves along the mandrel 3 having such a diameter and height, the cylindrical film 8
Even if the take-up speed is increased, the diameter of the cylindrical film 8 may become smaller than the diameter of the annular slit 2, making the bubble unstable, or the change in diameter may be too large when the cylindrical film, once thin, expands. It will not explode or explode. The surface (side surface) of the mandrel 3 is provided with a large number of through holes 4 that penetrate from the inside and outside. Through hole 4
The pore size is usually 0.5 to 20 mm, preferably 1 to 5 mm.
having a major axis or minor axis in the range of mm,
The ratio of the total open area of the through holes 4 to the total surface area (area of the side surface) of the mandrel 3, that is, the open area ratio is usually in the range of 10 to 70%, preferably 20 to 40%. The shape of the through hole 4 may be circular, oval,
Examples include a square shape, a diamond shape, a cross shape, or a combination thereof, and examples of the hole arrangement include a staggered shape or a parallel shape. Examples of the shape and arrangement of the through holes 4 are shown in FIGS. 2 to 7. The surface of the mandrel 3 has a high thermal conductivity in order to stabilize bubbles well when the cylindrical film 8 is started up.
It is best to use materials that exceed 10 kcal/m・hr・℃, specifically, for example, aluminum, iron,
Examples include copper, stainless steel, and brass. Among these, iron is preferably used from the viewpoint of workability, thermal conductivity, and durability. The thinner the wall thickness of the mandrel is, the faster the bubbles are stabilized when the cylindrical film is raised, so it is preferable, but if the wall thickness is too thin, problems will arise in terms of the strength and durability of the mandrel. Therefore, the wall thickness of the mandrel 3 is usually 0.5 to 5 mm, preferably 0.5 to 5 mm, from the viewpoint of workability, strength, and durability.
A range of 0.5 to 2 mm is appropriate. If the surface of the mandrel 3 that does not have the through holes 4 is too smooth, the molten cylindrical film 8 will stick to it and cause the cylindrical film 8 to break. ,
It is best to form irregularities of 0.01 mm or more. By providing the above-mentioned through holes 4 or providing unevenness on the surface of the mandrel 3, the stabilization of bubbles when the cylindrical film 8 is started up is significantly improved. 8
An air layer is formed between the mandrel and the mandrel 3, which has the effect of lowering the pulling resistance. Furthermore, if the mandrel 3 is placed too far away from the die 1, the cylindrical film 8 extruded from the die 1 may become thinner and then expand again, which may cause breakage. The distance from the surface of the mandrel 3 to the starting point of the substantially same diameter part is 1/10 of the diameter of the annular slit 2.
It is desirable that the value is 1 or less. When performing inflation molding using the method of the present invention, it is important to set the blow ratio to about 2 or more and the draft rate (take-up speed/extrusion speed) to about 4 or more to ensure molding stability and balance the strength of the product film. etc. is desirable. Hereinafter, the method of the present invention will be further explained with reference to Examples, but the present invention is not limited to the following Examples unless the gist thereof is exceeded. Examples 1 to 3 High-density polyethylene {manufactured by Mitsubishi Chemical Industries, Ltd., Novatec R4000F, melt index: 0.05 g/
10 minutes, density: 0.954 g/cm 3 , melt tension: 9 g} (Novatec is a registered trademark of Mitsubishi Chemical Industries, Ltd.).
The cylinder temperature is 200℃,
Under the conditions of die head temperature 200℃ and die temperature 200℃,
Inflation molded. The mandrel is a hollow cylindrical body made of iron with a length of 500 mm and a wall thickness of 1 mm. On its side, through holes of 2 mm diameter are provided in the shape and arrangement as shown in Figure 2 at an open area ratio of 30%. . The distance from the die surface to the start of the substantially same diameter portion of the mandrel was 16 mm. The bubble expansion started at a position 350 mm from the die surface. The blow-up ratio is kept constant at 3.8, and the take-up speed is
24m/min (Example 1), 30m/min (Example 2), 60
m/min (Example 3) to obtain films with thicknesses of 25 μm, 20 μm, and 10 μm, respectively, and evaluations were made based on bubble stabilization time, bubble stability, and strength balance of the obtained films. The bubble stabilization time was expressed as the time (minutes) from when the molten cylindrical film came into contact with the mandrel surface until it became possible to form a film in a stable state. Bubble stability was evaluated by visually observing the bubbles and evaluating them in three stages: good, slightly unstable, and unstable. Regarding the strength balance, tear the obtained film by hand in the pulling direction and check whether the cut goes vertically, horizontally, or diagonally.If the cut goes diagonally, it is considered to have good strength balance. Those that were uneven in one direction were considered defective. The results are shown in Table 1. Comparative Example 1 The mandrel in Example 1 was replaced with a mandrel in which grooves of 0.7 mm depth and 0.5 mm width were intersected with each other at a pitch of 1 mm to form a mesh-like unevenness on the surface of a 500 mm long aluminum cylindrical body. Inflation molding was performed and evaluated in the same manner as in Example 1, except that a molded material was used. The results are shown in Table 1. Comparative Examples 2 and 3 The same equipment as Example 1 was used except that the mandrel of Example 1 was replaced with a 35 mm diameter one (Comparative Example 2), and the mandrel of Example 1 was removed (Comparative Example 3). Inflation molding was performed in the same manner and evaluated. The results are shown in Table 1. 【table】
第１図は本発明の方法に用いるインフレーシヨ
ンフイルム成形装置の一例を示す説明図である。
第２図〜第７図は貫通孔の形状及び配列の例を示
す図面である。
図中１はダイ、２は環状スリツト、３はマンド
レル、４は貫通孔、８は筒状フイルムをそれぞれ
示す。
FIG. 1 is an explanatory view showing an example of an inflation film forming apparatus used in the method of the present invention.
FIGS. 2 to 7 are drawings showing examples of the shape and arrangement of through holes. In the figure, 1 is a die, 2 is an annular slit, 3 is a mandrel, 4 is a through hole, and 8 is a cylindrical film.
Claims (1)
ンフレーシヨン成形するに当り、環状スリツトを
有するダイからポリオレフイン樹脂を筒状に押し
出し、押し出された溶融状態にある筒状フイルム
を、環状スリツトの径以上で環状スリツトの径の
1.3倍以下の径を有する下部から上部まで実質的
に同径で、且つ内外を貫通する多数の貫通孔を有
する筒状マンドレルに添わせて移動せしめ、次い
で膨張させながら引取ることを特徴とするインフ
レーシヨンフイルム成形方法。 ２ ポリオレフイン樹脂は密度0.935ｇ／cm3以上、
メルトインデツクス１ｇ／10分以下の高密度ポリ
エチレンであることを特徴とする特許請求の範囲
第１項に記載の方法。 ３ マンドレルは熱伝導率10kcal／ｍhr℃を超え
る熱良導体から構成されていることを特徴とする
特許請求の範囲第１項又は第２項に記載の方法。 ４ マンドレルはその側面全体に0.5〜20mmの孔
径を有する貫通孔が10〜70％の開孔率で設けられ
ていることを特徴とする特許請求の範囲第１項乃
至第３項のいずれかに記載の方法。 ５ ダイ表面からマンドレルの実質的に同径の部
分が初まる位置までの距離が環状スリツトの径の
１／１０以上１以下であることを特徴とする特許請求
の範囲第１項乃至第４項のいずれかに記載の方
法。 ６ インフレーシヨン成形はブロー比２以上、ド
ラフト率４以上として成形することを特徴とする
特許請求の範囲第１項乃至第４項のいずれかに記
載の方法。[Claims] 1. In inflation molding a polyolefin resin having a melt tension of 3 g or more, the polyolefin resin is extruded into a cylindrical shape from a die having an annular slit, and the extruded molten cylindrical film is molded into an annular shape. The diameter of the annular slit is greater than the diameter of the slit.
It is characterized in that it is moved along a cylindrical mandrel that has substantially the same diameter from bottom to top and that has a diameter of 1.3 times or less and has a large number of through holes passing through the inside and outside, and then is taken off while being expanded. Inflation film forming method. 2 Polyolefin resin has a density of 0.935g/ cm3 or more,
The method according to claim 1, wherein the method is made of high-density polyethylene having a melt index of 1 g/10 minutes or less. 3. The method according to claim 1 or 2, wherein the mandrel is made of a good thermal conductor with a thermal conductivity exceeding 10 kcal/mhr°C. 4. According to any one of claims 1 to 3, the mandrel is provided with through holes having a hole diameter of 0.5 to 20 mm on the entire side surface with an open area ratio of 10 to 70%. Method described. 5. Claims 1 to 4, characterized in that the distance from the die surface to the position where the substantially same diameter portion of the mandrel starts is 1/10 or more and 1 or less of the diameter of the annular slit. The method described in any of the above. 6. The method according to any one of claims 1 to 4, wherein the inflation molding is performed at a blow ratio of 2 or more and a draft rate of 4 or more.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP58234021A JPS60125623A (en) | 1983-12-12 | 1983-12-12 | Molding method of inflation film |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP58234021A JPS60125623A (en) | 1983-12-12 | 1983-12-12 | Molding method of inflation film |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPS60125623A JPS60125623A (en) | 1985-07-04 |
| JPH0450888B2 true JPH0450888B2 (en) | 1992-08-17 |
Family
ID=16964313
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP58234021A Granted JPS60125623A (en) | 1983-12-12 | 1983-12-12 | Molding method of inflation film |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPS60125623A (en) |
Families Citing this family (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| DE102005060979A1 (en) | 2005-12-20 | 2007-06-28 | Kiefel Extrusion Gmbh | Method and device for producing blown films of thermoplastics |
-
1983
- 1983-12-12 JP JP58234021A patent/JPS60125623A/en active Granted
Also Published As
| Publication number | Publication date |
|---|---|
| JPS60125623A (en) | 1985-07-04 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| RU2219198C2 (en) | Hot-molded sheet polypropylene foam | |
| US10974435B2 (en) | Method for producing foam blow-molded article | |
| JP2007075858A (en) | Method for producing pierced tube | |
| JPH0450888B2 (en) | ||
| US4204819A (en) | Shaping apparatus for tubular film | |
| US4251199A (en) | Stabilizer for resin bubbles | |
| JPS6049911A (en) | Formation of inflation film | |
| JPH0361575B2 (en) | ||
| JPS6142621B2 (en) | ||
| JPH0517022B2 (en) | ||
| JP2986993B2 (en) | Propylene resin foam sheet and method for producing the same | |
| CA1099467A (en) | Method and apparatus for shaping of tubular film | |
| JPH0246993Y2 (en) | ||
| JP4788414B2 (en) | Manufacturing method of perforated tube | |
| JP3792889B2 (en) | Film inflation molding method and apparatus | |
| JPS60101022A (en) | Forming method of inflation film | |
| JPS5939524A (en) | Chamber for forming inflation film | |
| JPS5913967B2 (en) | Molding method of tubular film | |
| JPH0452203B2 (en) | ||
| JP2500284B2 (en) | Inflation molding equipment | |
| KR820001881B1 (en) | Moulding process for pipe films | |
| JPH0757524B2 (en) | Manufacturing method of tubular film | |
| JPH01127315A (en) | Manufacture of modified film | |
| JPH0543502B2 (en) | ||
| JPH0247337B2 (en) |