JP4320985B2

JP4320985B2 - Method for extruding thermoplastic resin and method for producing thermoplastic resin film

Info

Publication number: JP4320985B2
Application number: JP2001236383A
Authority: JP
Inventors: 寛史三浦
Original assignee: Sumitomo Bakelite Co Ltd
Current assignee: Sumitomo Bakelite Co Ltd
Priority date: 2001-08-03
Filing date: 2001-08-03
Publication date: 2009-08-26
Anticipated expiration: 2021-08-03
Also published as: JP2003039528A

Description

【０００１】
【発明の属する技術分野】
本発明は異物を含まず外観や透明性が優れた成形品を得るための熱可塑性樹脂の押出方法および熱可塑性樹脂フィルムの製造方法である。
【０００２】
【従来の技術】
一般に溶融押出し法による熱可塑性樹脂成形品は樹脂の熱分解・熱変性による不純物の混入によりフィッシュ・アイ、ブツなどの異物が発生し、その外観・透明性・表面平滑性を著しく低下させている。そのため、これらの不純物をフィルターによってろ過することにより低減させる方法(例えば特開昭５９−１８６５８８号公報)が知られているが特に光学用途の熱可塑性樹脂フィルムにおいては十分ではなく、さらに濾過精度を上げるためにフィルターエレメントのメディアを細かくするとメディアの目詰まりから樹脂圧がメディアの耐圧に上昇するまでの時間が早くなり、連続生産が不可能となるか、あるいは樹脂圧が上がったためにメディアの目開きが起こり、濾過精度が低下するといった問題があった。
また、これらの不純物は純物質とは異なる物性を示すため、ダイス口金表面と樹脂との滑り性も異なることから、ダイラインの原因にもなっており、これらの問題が、フィルム外観、平滑性を著しく低下させていた。
【０００３】
【発明が解決しようとする課題】
本発明は、不純物や異物がなく、かつダイラインと言われる押出しの流れ方向に現れるスジがない表面の外観および平滑性に優れた成形品を得ることのできる熱可塑性樹脂の押出方法および熱可塑性樹脂フィルムの製造方法を提供するものである。
【０００４】
【課題を解決するための手段】
本発明者らは従来、除去し切れなかった熱可塑性樹脂フィルム中の不純物や異物であるブツ、フィッシュ・アイを除去し、また、表面平滑性を低下させるダイラインを低減させた良好な熱可塑性樹脂成形品を得んとして鋭意研究した結果、これらの原因として考えられるゲル化異物はフィルターメディアを通過しているのではなく、主としてフィルター２次側の壁面滞留によりゲル化 (高分子量化)あるいは分解していることを突き止め、この壁面滞留部分を含む樹脂を系外に排出するか、または後工程で除去する部分もしくは外観が問題にならない部分に流すことにより外観を重要視する部分はフィッシュ・アイ、ブツ、ダイライン等のない極めて良好な熱可塑性樹脂成形品が得られるとの知見を得、本発明を完成するに至ったものである。
【０００５】
即ち本発明は、
（１）溶融樹脂流路の内壁付近を流れる樹脂を前記流路の中心部寄りを流れる樹脂と分流させるための隔壁を有し、前記隔壁と前記流路内壁とで作られる流路断面積が流れ方向に向かって小となる分流手段を有する熱可塑性樹脂の押出方法。
（２）前記隔壁と前記流路内壁とで作られる流路を通過する樹脂を押出機系外に排出することを特徴とする（１）の熱可塑性樹脂の押出方法。
（３）前記隔壁と前記流路内壁とで作られる流路を通過する樹脂をダイの一定部分のみに供給することを特徴とする（１）の熱可塑性樹脂の押出方法。
（４）前記隔壁と前記流路内壁とで作られる流路が２以上の流路に分岐する（１）〜（３）の熱可塑性樹脂の押出方法。
（５）前記隔壁と前記流路内壁とで作られる流路がＴダイまたはコートハンガーダイの両端に向かう位置に設置されていることを特徴とする（４）の熱可塑性樹脂の押出方法。
（６）（１）〜（５）の熱可塑性樹脂の押出方法を用いて製造された熱可塑性樹脂成形品。
（７）少なくとも押出機とフィルターとＴダイまたはコートハンガーダイを有する製造装置を用いて製造する熱可塑性樹脂フィルムの製造方法において、フィルターとＴダイまたはコートハンガーダイの間に溶融樹脂流路の内壁付近を流れる樹脂を前記流路の中心部寄りを流れる樹脂と分流させるための隔壁を有し、前記隔壁と前記流路内壁とで作られる流路が流れ方向に向かって２つに分岐すると共にその流路断面積が小となり、Ｔダイまたはコートハンガーダイの両端に向かう位置に接続する分流手段を有することを特徴とする熱可塑性樹脂フィルムの製造方法。
である。
【０００６】
【発明の実施の形態】
前記壁面滞留部分を含む樹脂は、流路の内壁に沿って流れるため、溶融樹脂流路の内壁付近を流れる樹脂を隔壁によりまず分流させる事が必要である。このことにより、流路の中心部寄りを流れる樹脂は、壁面滞留物を含まない樹脂となり、この部分の樹脂によって成形された製品は良好な外観を有する。
分流させた壁面滞留物を含む樹脂は、系外に排出するか、または後工程で除去する部分もしくは外観が問題にならない一定の部分（複数も可）に流すことが望ましい。したがって、環状に分流された壁面滞留物を含む樹脂の流路は、流れ方向に向かってその断面積を小さくして行った方が後の処理のために都合が良い。例えば、成形品がフィルムの場合には、分流された壁面滞留物を含む樹脂をフィルム両端に集め、後工程で両端部を切断除去することで、良好な外観のフィルムを得ることができる。押出成形によりフィルムを製造する場合には、一般に両端部をカットすることが多いので、このようにしてもフィルムの収率が低下することはない。このように一旦分流した壁面滞留物を含む樹脂を再度合流させる場合は、後に除去したり、外観不良が問題とならない部分に壁面滞留物を集約させるため、環状の流路全周長に対して０．００５〜０．２５の割合の円弧長となるように流れ方向に向かって流路断面積を小さくして行けば、壁面滞留物が良質な部分に混入することがなく、また壁面滞留物の流路抵抗が大きくなりすぎることもなく好ましいが、特に限定はしない。
溶融樹脂流路の内壁と隔壁との距離すなわち環状に分流された壁面滞留物を含む樹脂の流路高さは、特に限定はしないが、壁面滞留物を十分に分流でき、樹脂の無駄が少ない範囲としては、分流前の流路内径（Ｄ）に対する分流流路高さ（ｈ）の比（ｈ／Ｄ）が、０．０５〜０．１５程度が好ましい。また、このたかさ（ｈ）は樹脂流れ方向にその大きさが変化しても良い。
【０００７】
【実施例】
以下、図面に従い本発明の実施例について詳しく説明するが、本発明はこれらの実施例に限定されるものではない。
＜実施例１＞
本発明の第１の実施例は、第１図に示すように、分流器（１）を溶融樹脂流路（２）内に挿入することで、溶融樹脂流路（２）内に隔壁（３）を形成させ、壁面滞留物を含む樹脂の環状流路を形成するものである。分流器（１）を挿入する溶融樹脂流路（２）は、第３図に示すようにダイス（Ｔダイもしくはコートハンガーダイ）（２１）直前のジョイント管（２２）とした。ジョイント管（２２）の壁面には、フィルタ（２３）で発生した壁面滞留樹脂も流れており、この部分で滞留樹脂を分離する事が望ましい。本実施例は第１図に示すように、溶融樹脂流路（２）の壁面を流れる滞留樹脂を２つに分離後、各々を小さく絞ってＴダイもしくはコートハンガーダイ（２１）の両端部に流れ込むような構造となっており、環状流路を流れる樹脂は下流に行くに従いダイス両端部に接続する部分に集められ、孔（４）を通って再び内側の流れに合流する。分流前の流路内径（Ｄ）に対する分流流路高さ（ｈ）の比（ｈ／Ｄ）は約０．０７５である。また、環状流路は、全周長に対して約０．０１の割合の円弧長まで絞った。
【０００８】
＜実施例２＞
第２図は、本発明の別の実施例を示す図であり、実施例１と同様に分流器（１１）と溶融樹脂流路（１２）で構成されるものでるが、絞られた樹脂を再合流させることなく溶融樹脂流路（１２）に設けた孔（１４）を通して系外に排出した。
＜実施例３＞
ポリエーテルサルホンＰＥＳ４１００Ｇ(住友化学工業（株）社製)を５０ｍφ押出機（２４）で押出し、実施例１のようにジョイント管（２２）に本発明を適用して、樹脂流路をコートハンガーダイ（２１）から吐出させ、帯電固定法により外径３００ｍｍφの冷却ロール（２５）に密着固定させて周速度２．００ｍ/ｍｉｎで引き取り、３００μｍ厚で８００ｍｍ幅のフィルムを押出した。このフィルムの両端をスリッターによりカットし、６００ｍｍ幅のフィルムを作製した。異物の評価はフィルム全幅を一方の端から▲１▼〜▲６▼まで６分割(100mmピッチ)し、その異物数を計測した。ダイラインの評価は一番大きなダイラインをｚｙｇｏ社製の表面粗さ計により測定し、同等の高さのダイライン数を計測した。
【０００９】
＜比較例＞
ジョイント管（２２）を通常の樹脂流路とし、本発明の分流器（１）を挿入しない状態で、実施例３と同様にフィルムを作製し、評価した。
表１は本発明の実施例３および比較例によって作製したフィルムの異物個数、ダイラインの本数を示す。表１に示すように、本発明を用いた実施例３では、ほとんどの異物が両端のカット部に集まっており、▲１▼〜▲６▼までの６００ｍｍ幅のフィルム部分を比較すると、異物個数は圧倒的に減少した。また、ダイラインについても本発明は効果的であることがわかった。
【００１０】
【表１】

【００１１】
【発明の効果】
本発明の製造方法に従うと、従来の溶融押出し法で利用されていたフィルトレーション装置の２次側、およびダイス内の壁面滞留によって発生した壁面滞留物を製品に混入させることなく、また壁面滞留物の付着によって起こるダイラインの発生を著しく押さえることができ、外観の非常に優れた熱可塑性樹脂成形物を製造することができる。
例えば、光学特性および表面平滑性を必要とする光学用途やディスプレイ分野においては、本発明の製造方法によって押出したフィルムはＴＮ，ＳＴＮ，ＴＦＴなどの液晶ディスプレイにおけるプラスチック基板用途に利用できるほか、光記録に用いられるディスク用フィルムにも利用が可能であり、その工業的価値は極めて高い。
【図面の簡単な説明】
【図１】本発明の一実施例を示す図である。
【図２】本発明の他の実施例を示す図である。
【図３】本発明の実施例を好適に用いることのできる押出装置を示すブロック図である。
【符号の説明】
１分流器
２溶融樹脂流路
３隔壁
４孔
１１分流器
１２溶融樹脂流路
１３隔壁
１４孔
２１ダイス
２２ジョイント管
２３フィルタ
２４押出機
２５ロール[0001]
BACKGROUND OF THE INVENTION
The present invention is a method for extruding a thermoplastic resin and a method for producing a thermoplastic resin film in order to obtain a molded article that does not contain foreign substances and has excellent appearance and transparency.
[0002]
[Prior art]
In general, thermoplastic resin molded products by the melt extrusion method generate foreign substances such as fish, eyes and butts due to contamination by impurities caused by thermal decomposition and thermal denaturation of the resin, and the appearance, transparency and surface smoothness of the molded product are significantly reduced. . Therefore, a method for reducing these impurities by filtering with a filter (for example, Japanese Patent Application Laid-Open No. 59-186588) is known, but it is not sufficient particularly for a thermoplastic resin film for optical use, and the filtration accuracy is further improved. If the filter element media is made finer to increase the time from the clogging of the media until the resin pressure rises to the pressure resistance of the media, the continuous production becomes impossible or the media pressure increases due to the increased resin pressure. There was a problem that opening occurred and the filtration accuracy was lowered.
In addition, since these impurities exhibit physical properties different from those of pure substances, the slipperiness between the die die surface and the resin is also different, and this also causes die lines. It was significantly reduced.
[0003]
[Problems to be solved by the invention]
The present invention relates to a method for extruding a thermoplastic resin and a thermoplastic resin, which are free of impurities and foreign matters, and are capable of obtaining a molded article having excellent surface appearance and smoothness free from streaks appearing in the direction of extrusion called a die line. A method for producing a film is provided.
[0004]
[Means for Solving the Problems]
The present inventors have heretofore removed excellent impurities such as impurities and foreign matters in thermoplastic resin films that could not be completely removed, and reduced die lines that reduce surface smoothness. As a result of earnest research on obtaining molded products, gelled foreign substances considered to be the cause of these are not passing through the filter media, but are mainly gelled (high molecular weight) or decomposed due to wall retention on the secondary side of the filter. The part that attaches importance to the appearance by discharging the resin containing the wall staying part to the outside of the system or flowing it to the part that is removed in the subsequent process or the part where the appearance does not become a problem is used. The present inventors have obtained the knowledge that an extremely good thermoplastic resin molded article free from lumps and die lines can be obtained, and have completed the present invention.
[0005]
That is, the present invention
(1) A partition for dividing the resin flowing in the vicinity of the inner wall of the molten resin channel with the resin flowing near the center of the channel, and a channel cross-sectional area formed by the partition and the channel inner wall A method for extruding a thermoplastic resin having a diversion means that decreases in the flow direction.
(2) The method for extruding a thermoplastic resin according to (1), wherein the resin passing through a flow path formed by the partition wall and the inner wall of the flow path is discharged out of the extruder system.
(3) The method for extruding a thermoplastic resin according to (1), wherein a resin passing through a flow path formed by the partition wall and the inner wall of the flow path is supplied only to a certain portion of the die.
(4) The method for extruding a thermoplastic resin according to (1) to (3), wherein a flow path formed by the partition wall and the flow path inner wall branches into two or more flow paths.
(5) The method for extruding a thermoplastic resin according to (4), characterized in that a flow path formed by the partition wall and the inner wall of the flow path is installed at positions facing both ends of the T die or the coat hanger die.
(6) A thermoplastic resin molded article produced by using the thermoplastic resin extrusion method of (1) to (5).
(7) In the method of manufacturing a thermoplastic resin film manufactured using a manufacturing apparatus having at least an extruder, a filter, and a T die or a coat hanger die, the inner wall of the molten resin flow path between the filter and the T die or the coat hanger die A partition for separating the resin flowing in the vicinity from the resin flowing near the center of the channel, and the channel formed by the partition and the inner wall of the channel branches into two in the flow direction; A method for producing a thermoplastic resin film, characterized in that the flow passage cross-sectional area is small, and there is a flow dividing means connected to positions toward both ends of a T die or a coat hanger die.
It is.
[0006]
DETAILED DESCRIPTION OF THE INVENTION
Since the resin including the wall surface staying portion flows along the inner wall of the flow path, it is necessary to first divert the resin flowing in the vicinity of the inner wall of the molten resin flow path by the partition walls. As a result, the resin that flows near the center of the flow path becomes a resin that does not contain wall residue, and a product molded from this portion of the resin has a good appearance.
It is desirable to discharge the resin containing the separated wall residue to the outside of the system or to flow to a part to be removed in a subsequent process or to a certain part (or a plurality of parts) whose appearance does not matter. Therefore, it is more convenient for subsequent processing that the flow path of the resin containing the wall residue accumulated in the annular shape is reduced in cross section in the flow direction. For example, in the case where the molded product is a film, a resin having a good appearance can be obtained by collecting the resin containing the separated wall surface residue on both ends of the film and cutting and removing both ends in a subsequent process. In the case of producing a film by extrusion molding, since both ends are generally cut in many cases, the yield of the film is not lowered even in this way. In this way, when the resin containing the wall surface debris once diverted is joined again, the wall surface debris is collected in a part that is removed later or the appearance defect does not become a problem. If the cross-sectional area of the flow path is reduced toward the flow direction so that the arc length is 0.005 to 0.25, the wall residue will not be mixed into a good quality part, and the wall residue Although it is preferable that the flow path resistance does not become too large, there is no particular limitation.
The distance between the inner wall of the molten resin flow path and the partition wall, that is, the height of the flow path of the resin including the wall surface debris divided in an annular shape is not particularly limited, but the wall surface debris can be sufficiently diverted and the resin is not wasted. As a range, the ratio (h / D) of the flow path height (h) to the flow path inner diameter (D) before the flow split is preferably about 0.05 to 0.15. Further, this bulk (h) may change in size in the resin flow direction.
[0007]
【Example】
Hereinafter, examples of the present invention will be described in detail with reference to the drawings. However, the present invention is not limited to these examples.
<Example 1>
As shown in FIG. 1, the first embodiment of the present invention inserts a flow divider (1) into the molten resin flow path (2), so that the partition wall (3 ) To form an annular flow path of resin containing wall surface debris. The molten resin flow path (2) into which the flow divider (1) is inserted was a joint pipe (22) immediately before a die (T die or coat hanger die) (21) as shown in FIG. The wall surface staying resin generated by the filter (23) also flows on the wall surface of the joint pipe (22), and it is desirable to separate the staying resin at this portion. In this embodiment, as shown in FIG. 1, after the staying resin flowing on the wall surface of the molten resin flow path (2) is separated into two, each is squeezed small to both ends of the T die or coat hanger die (21). The resin flowing through the annular flow path is collected at the portion connected to both ends of the die as it goes downstream, and merges with the inner flow again through the hole (4). The ratio (h / D) of the flow path height (h) to the flow path inner diameter (D) before the flow is about 0.075. In addition, the annular flow path was narrowed to an arc length of about 0.01 with respect to the entire circumference.
[0008]
<Example 2>
FIG. 2 is a diagram showing another embodiment of the present invention, which is composed of a flow divider (11) and a molten resin flow path (12) as in the first embodiment. It was discharged out of the system through the hole (14) provided in the molten resin flow path (12) without re-merging.
<Example 3>
Polyethersulfone PES4100G (manufactured by Sumitomo Chemical Co., Ltd.) was extruded with a 50 mφ extruder (24), and the present invention was applied to the joint pipe (22) as in Example 1 to coat the resin flow path with a coat hanger. The film was discharged from the die (21), closely fixed to a cooling roll (25) having an outer diameter of 300 mmφ by a charge fixing method, taken up at a peripheral speed of 2.00 m / min, and a film having a thickness of 300 μm and a width of 800 mm was extruded. Both ends of this film were cut with a slitter to produce a 600 mm wide film. For the evaluation of foreign matter, the entire width of the film was divided into six (1) to (6) from one end (100 mm pitch), and the number of foreign matters was measured. Evaluation of the die line measured the largest die line with the surface roughness meter made from zygo, and measured the number of die lines of the same height.
[0009]
<Comparative example>
A film was prepared and evaluated in the same manner as in Example 3 except that the joint pipe (22) was a normal resin flow path and the flow divider (1) of the present invention was not inserted.
Table 1 shows the number of foreign matters and the number of die lines of the films prepared according to Example 3 and Comparative Example of the present invention. As shown in Table 1, in Example 3 using the present invention, most foreign matters are gathered at the cut portions at both ends, and the number of foreign matters is compared when comparing film portions of 600 mm width from (1) to (6). Decreased overwhelmingly. Moreover, it turned out that this invention is effective also about die line.
[0010]
[Table 1]

[0011]
【The invention's effect】
According to the production method of the present invention, the secondary side of the filtration apparatus used in the conventional melt extrusion method, and the wall surface retention generated by the wall surface retention in the die are not mixed into the product, and the wall surface retention It is possible to remarkably suppress the occurrence of die lines caused by the adhesion of objects, and it is possible to produce a thermoplastic resin molded article having an excellent appearance.
For example, in the optical application and display fields that require optical properties and surface smoothness, the film extruded by the production method of the present invention can be used for plastic substrates in liquid crystal displays such as TN, STN, and TFT, as well as optical recording. It can also be used for a film for a disk used in the field, and its industrial value is extremely high.
[Brief description of the drawings]
FIG. 1 is a diagram showing an embodiment of the present invention.
FIG. 2 is a diagram showing another embodiment of the present invention.
FIG. 3 is a block diagram showing an extrusion apparatus that can be suitably used in an embodiment of the present invention.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Splitter 2 Molten resin flow path 3 Partition 4 Hole 11 Splitter 12 Molten resin flow path 13 Partition 14 Hole 21 Die 22 Joint pipe 23 Filter 24 Extruder 25 Roll

Claims

A thermoplastic resin extrusion flow divider having a molten resin flow path, because that causes flow min the resin flowing through the central portion side of the resin before and Symbol molten resin flow path flowing near the inner wall of the molten resins flow path Patent that the partition wall along the flow direction of the resin having the molten resin passage, becomes small toward the further the partition wall and the flow passage inner wall direction flow path cross-sectional area made flow to
A diverter for extruding thermoplastic resin.

The flow path formed by the partition wall and the inner wall of the molten resin flow path is divided into two or more flow paths.
The diverter for extruding a thermoplastic resin according to claim 1.

Molten resin passing through a flow path formed by the partition and the inner wall of the molten resin flow path
3. The heatable material according to claim 1, wherein the heat is discharged from the discharge port to the outside of the thermoplastic resin extruding flow divider.
Shunt for plastic resin extrusion.

Extruder (E), extruding diverter (FD), and extruding diverter (FD)
A die (D) attached to the discharge port of the thermoplastic resin,
The heat splitter is an extrudate for extruding a thermoplastic resin according to claim 3.
Plastic resin extrusion equipment.

The resin passing through the flow path formed by the partition wall and the inner wall of the molten resin flow path
The thermoplastic according to claim 4, wherein the thermoplastic resin is supplied only to a predetermined portion of the die (D) through the discharge port.
Extruder for functional resin.

A flow path formed by the partition wall and the inner wall of the molten resin flow path is the die (D).
It is installed in the position which goes to both ends, For thermoplastic resins of Claim 5 characterized by the above-mentioned
Extrusion equipment.

At least the extruder (E1), the filter (F1) and the T-die (T1)
Is an extrusion apparatus having a coat hanger die (H1), the filter (F1
) And T die (T1) or coat hanger die (H1)
In the channel, the resin that flows near the inner wall of the molten resin channel and the center of the molten resin channel
A partition along the molten resin flow path for diverting the resin,
A channel formed by the partition and the inner wall of the molten resin channel
Branching into two or more in the flow direction, the flow path cross-sectional area is small, and T
It is connected to a position toward both ends of the (T1) or coat hanger die (H1).
An extrusion apparatus for thermoplastic resin.

Method of extruding thermoplastic resin having a step of extruding resin with extrusion device (E2)
The thermoplastic device according to any one of claims 4 to 7, wherein the extrusion device (E2) is a method.
A method for extruding a thermoplastic resin, which is an extrusion apparatus for resin.

Production of a thermoplastic film having a process of extruding a resin with an extrusion device (E3)
A thermoplastic method as claimed in any one of claims 4 to 7, wherein the extrusion device is a manufacturing method.
For producing a thermoplastic film using an extruding apparatus for a conductive resin.