JP3273487B2 - Method for producing polyolefin resin foam pipe - Google Patents
Method for producing polyolefin resin foam pipeInfo
- Publication number
- JP3273487B2 JP3273487B2 JP16285795A JP16285795A JP3273487B2 JP 3273487 B2 JP3273487 B2 JP 3273487B2 JP 16285795 A JP16285795 A JP 16285795A JP 16285795 A JP16285795 A JP 16285795A JP 3273487 B2 JP3273487 B2 JP 3273487B2
- Authority
- JP
- Japan
- Prior art keywords
- foaming
- pipe
- furnace
- polyolefin resin
- foamed
- 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 - Fee Related
Links
Landscapes
- Molding Of Porous Articles (AREA)
- Heating, Cooling, Or Curing Plastics Or The Like In General (AREA)
- Extrusion Moulding Of Plastics Or The Like (AREA)
Description
【０００１】[0001]
【産業上の利用分野】この発明は，空調用その他の熱媒
体輸送配管の被覆断熱材等の用途に使用されるポリオレ
フィン系樹脂発泡パイプを連続的に製造するポリオレフ
ィン系樹脂発泡パイプの製造方法に関する。BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing a polyolefin resin foam pipe for continuously producing a polyolefin resin foam pipe for use as a coating and heat insulating material for air-conditioning and other heat medium transport pipes. .
【０００２】[0002]
【従来の技術】ポリオレフィン系樹脂発泡パイプの製造
方法には，シート押出・発泡方式およびチューブ押出・
発泡方式の２つの方式がある。前記シート押出・発泡方
式は，架橋剤および発泡剤を配合したポリオレフィン系
樹脂組成物をシート押出機でシート状に押し出し，連続
的に架橋・発泡させて発泡シートを得，これを所定幅に
スリットし，この所定幅のスリット発泡シートを縦添い
方式にてパイプフォーミングしながらその両縁部をハン
ダコテ等で熱融着する方法である。すなわち，工程とし
ては，（１）シート押出，（２）シート発泡，（３）発
泡シート引巻取り，（４）発泡シート送り出し，（５）
スリッティング，（６）スリット発泡シートの引巻取
り，（７）スリット発泡シートの送り出し，（８）パイ
プフォーミング，（９）発泡パイプ引巻取り，の順の９
工程によって発泡パイプを製造する。この場合，（１）
〜（３）工程はタンデムの工程が可能であり，（４）〜
（６）工程もテンデムの工程が可能であり，（７）〜
（９）の工程もタンデムの工程が可能である。したがっ
て，タンデム工程を単位とすれば３工程である。このシ
ート押出・発泡方式では一般に，発泡剤としてアゾ系有
機発泡剤等が使用されている。2. Description of the Related Art Polyolefin resin foam pipes are produced by sheet extrusion / foaming or tube extrusion / foaming.
There are two types of foaming methods. In the sheet extrusion / foaming method, a polyolefin-based resin composition containing a crosslinking agent and a foaming agent is extruded into a sheet by a sheet extruder, and is continuously crosslinked / foamed to obtain a foamed sheet. In this method, both edges of the slit foam sheet having a predetermined width are heat-sealed with a soldering iron or the like while being pipe-formed by a vertical lining method. That is, the process includes (1) sheet extrusion, (2) sheet foaming, (3) foam sheet winding, (4) foam sheet feeding, and (5)
Slitting, (6) Slit foam sheet take-up, (7) Slit foam sheet feed, (8) Pipe forming, (9) Foam pipe take-up, 9
The process produces foamed pipes. In this case, (1)
The process (3) can be a tandem process, and the process (4)
The (6) process can also be a tendem process, and (7) to
The step (9) can be a tandem step. Therefore, if the tandem process is used as a unit, there are three processes. In this sheet extrusion / foaming system, an azo organic foaming agent or the like is generally used as a foaming agent.
【０００３】後者のチューブ押出・発泡方式は，発泡剤
を配合したポリオレフィン系樹脂組成物をチューブ押出
機でチューブ状に押し出し，連続的に発泡させる方法で
ある。すなわち，工程としては，（１）チューブ押出・
発泡，（２）発泡パイプ引巻取り，の順の２工程によっ
て発泡パイプを製造する。この２工程はタンデムの工程
が可能である。したがって，タンデム工程を単位とすれ
ば１工程で済む。このチューブ押出・発泡方式では，一
般にフロンガスあるいはブタン等の揮発性溶剤を発泡剤
として用いる。The latter method is a method of extruding a polyolefin resin composition containing a foaming agent into a tube by a tube extruder and continuously foaming the composition. That is, as the process, (1) tube extrusion
A foamed pipe is manufactured by two steps of foaming and (2) winding and winding of the foamed pipe. These two steps can be tandem steps. Therefore, if the tandem process is a unit, only one process is required. In this tube extrusion / foaming method, a volatile solvent such as Freon gas or butane is generally used as a foaming agent.
【０００４】[0004]
【発明が解決しようとする課題】上記のシート押出・発
泡方式は，上述の通り，シート押出から製品完成までの
工程数がきわめて多く，必要作業人数が多く，時間がか
かり，また，各工程における線速が遅いことからも時間
がかかり，生産性が低い。また，パイプフォーミングす
るのに必要な幅に発泡シートをスリットする際に，余分
な切れ端が生じる等により歩留りが低い。さらに，パイ
プフォーミングする過程で合わせ目を融着するため，製
品パイプの外面に熱融着跡（通称シーム面）が残り，外
観が良好でない。As described above, the sheet extrusion / foaming method requires an extremely large number of steps from sheet extrusion to product completion, requires a large number of workers, takes a long time, and requires a long time in each step. It takes time because of the low linear velocity, and the productivity is low. Further, when slitting the foam sheet to a width necessary for pipe forming, an extra cut is generated, and the yield is low. Furthermore, since seams are fused during the process of pipe forming, traces of thermal fusion (commonly called seam surfaces) remain on the outer surface of the product pipe, and the appearance is not good.
【０００５】一方，チューブ押出・発泡方式は，生産
性，歩留りの点で優れ，製品の外面に熱融着跡がないと
いう長所があるが，発泡剤として用いるフロンガスはオ
ゾン層破壊の問題で有害であり，使用が規制されてい
る。また，ブタン等の揮発性溶剤は人体に有害であり，
かつ可燃性を持つという欠点がある。[0005] On the other hand, the tube extrusion / foaming method is excellent in productivity and yield, and has the advantage that there is no trace of heat fusion on the outer surface of the product. However, CFC used as a foaming agent is harmful due to the problem of destruction of the ozone layer. And its use is regulated. In addition, volatile solvents such as butane are harmful to the human body,
It has the drawback of being flammable.
【０００６】一般的にシート押出・発泡方式に用いる有
機発泡剤には有害性，可燃性の問題はないので，その種
の有機発泡剤を用いたチューブ押出・発泡方式により発
泡パイプを製造できればよいのであるが，次の理由によ
りそれができなかった。すなわち，フロンガスや揮発性
溶剤は，揮発温度が常温なので押出機内では高圧のため
に揮発作用を抑えられるが，成形材料が押出機を出て大
気圧下にさらされると直ちに揮発発泡し発泡パイプがで
きる。したがって，得られた発泡パイプをコンベア等で
搬送しても，特に支障はない。しかし，有機発泡剤の発
泡温度は２００℃程度と高いので，チューブ押出機を出
てすぐに架橋・発泡（有機発泡剤の場合は通常，発泡倍
率を高めるために架橋反応も起こさせる）はせず，この
未架橋未発泡チューブ状樹脂を架橋・発泡炉内でローラ
等により搬送すると，製品パイプの外面にローラ等の跡
がついてしまったり，均等発泡ができないという問題が
あった。このため，チューブ押出・発泡方式に化学発泡
する有機発泡剤を用いることはできなかった。なお，シ
ート押出・発泡方式の場合は，押出機を出た後，未架橋
未発泡のまま架橋・発泡炉内をコンベアで搬送しても，
パイプと異なりシート状であるからコンベア跡がつきに
くく，均一発泡するので，このような有機発泡剤を用い
ることができる。Generally, organic foaming agents used in sheet extrusion / foaming systems do not have harmful or flammable problems, so it is sufficient if a foamed pipe can be manufactured by a tube extrusion / foaming system using such an organic foaming agent. However, we could not do that for the following reasons. That is, since the volatilization temperature of Freon gas and volatile solvent is normal temperature, the volatilizing action can be suppressed due to the high pressure in the extruder. However, when the molding material leaves the extruder and is exposed to the atmospheric pressure, it volatilizes and foams immediately. it can. Therefore, there is no particular problem even if the obtained foamed pipe is conveyed by a conveyor or the like. However, since the foaming temperature of the organic foaming agent is as high as about 200 ° C., crosslinking and foaming are performed immediately after leaving the tube extruder (in the case of an organic foaming agent, a crosslinking reaction is usually caused to increase the foaming ratio). However, when the uncrosslinked unfoamed tubular resin is conveyed by a roller or the like in a crosslinking / foaming furnace, there is a problem that a trace of the roller or the like is left on the outer surface of the product pipe and uniform foaming cannot be performed. For this reason, it was not possible to use an organic foaming agent that chemically foams in the tube extrusion / foaming method. In the case of the sheet extrusion / foaming method, after exiting the extruder, even if conveyed through a cross-linking / foaming furnace on a conveyor without being cross-linked and unfoamed,
Unlike a pipe, since it is sheet-shaped, it does not easily leave traces of the conveyor and foams uniformly, so such an organic foaming agent can be used.
【０００７】本発明は上記事情に鑑みてなされたもの
で，生産性および歩留りが高く，かつ製品パイプの外面
に熱融着跡を発生させず，しかも，有害物を排出するこ
とのないポリオレフィン系樹脂発泡パイプの製造方法を
提供することを目的とする。The present invention has been made in view of the above circumstances, and is a polyolefin-based material which has high productivity and yield, does not generate heat fusion marks on the outer surface of a product pipe, and does not discharge harmful substances. An object of the present invention is to provide a method for manufacturing a resin foam pipe.
【０００８】[0008]
【課題を解決するための手段】上記課題を解決する本発
明のポリオレフィン系樹脂発泡パイプの製造方法は，少
なくとも架橋剤および有機発泡剤を配合してなるポリオ
レフィン系樹脂組成物をチューブ押出機に供給し，この
チューブ押出機から押し出された未架橋未発泡チューブ
状樹脂を架橋・発泡炉内で下側から吹き上げる熱風で浮
かせながら搬送し，この熱風により架橋・発泡させて発
泡パイプを得ることを特徴とする。In order to solve the above-mentioned problems, a method for producing a polyolefin resin foam pipe according to the present invention comprises supplying a polyolefin resin composition containing at least a crosslinking agent and an organic foaming agent to a tube extruder. The uncrosslinked unfoamed tubular resin extruded from the tube extruder is conveyed while floating with hot air blown up from below in a crosslinking and foaming furnace, and crosslinked and foamed with the hot air to obtain a foamed pipe. And
【０００９】[0009]
【作用】上記構成において，押出温度を発泡温度より低
い架橋温度よりさらに低く設定すると，チューブ押出機
を出た未架橋未発泡チューブ状樹脂は発泡温度以上の架
橋・発泡炉内を搬送されて架橋・発泡し，発泡パイプと
なるが，架橋・発泡炉内では未架橋未発泡チューブ状樹
脂は下から吹き上げる熱風により浮遊した状態で搬送さ
れるので，未架橋未発泡チューブ状樹脂の外面が変形す
ることはない。In the above configuration, if the extrusion temperature is set lower than the crosslinking temperature lower than the foaming temperature, the uncrosslinked unfoamed tubular resin exiting the tube extruder is conveyed through the crosslinking / foaming furnace at the foaming temperature or higher and crosslinked.・ Blows and forms a foamed pipe, but in a cross-linking / foaming furnace, the outer surface of the non-cross-linked unfoamed tubular resin is deformed because it is transported in a floating state by hot air blown up from below. Never.
【００１０】[0010]
【実施例】以下，本発明の一実施例を図面を参照して説
明する。図１は本発明の一実施例のポリオレフィン系樹
脂発泡パイプの製造方法を採用した発泡パイプ製造装置
の概略図，図２は図１における架橋・発泡炉の内部構造
を示す断面図である。チューブ押出機１は，成形材料を
投入するホッパ２，スクリュー３ａを内蔵したシリンダ
３，所定サイズのニップル・ダイス４ａを装着したヘッ
ド４を備えている。そして，チューブ押出機１の下流
に，チューブ押出機１から出た未架橋未発泡チューブ状
樹脂６’を架橋・発泡する架橋・発泡炉５，および発泡
パイプ６を引き取る発泡パイプ引取機７を配置してい
る。図示のチューブ押出機１は単軸スクリュウ３を持つ
が，二軸スクリュウでもよく，その他チューブ押出機自
体の構造は特に限定されない。また，図示の発泡パイプ
引取機７はロール式であるが，キャタピラ式その他でも
よい。An embodiment of the present invention will be described below with reference to the drawings. FIG. 1 is a schematic view of an apparatus for producing a foamed pipe employing a method for producing a polyolefin-based resin foamed pipe according to one embodiment of the present invention, and FIG. 2 is a sectional view showing the internal structure of a crosslinking / foaming furnace in FIG. The tube extruder 1 includes a hopper 2 for charging a molding material, a cylinder 3 having a screw 3a therein, and a head 4 having a nipple die 4a of a predetermined size. Downstream of the tube extruder 1, a cross-linking / foaming furnace 5 for cross-linking and foaming the uncross-linked unfoamed tubular resin 6 'coming out of the tube extruder 1, and a foam pipe take-up machine 7 for taking up the foam pipe 6 are arranged. are doing. Although the illustrated tube extruder 1 has a single screw 3, it may be a twin screw, and the structure of the tube extruder itself is not particularly limited. The illustrated foam pipe take-up machine 7 is a roll type, but may be a caterpillar type or the like.
【００１１】前記架橋・発泡炉５は，図２に示すよう
に，Ｖ形側壁を持つチューブ状樹脂搬送室１０，このチ
ューブ状樹脂搬送室１０のＶ形の下端部の開口溝１１，
その下方の圧力チャンバ１２，さらにその下方の熱風供
給ダクト１３，上部の熱風排気ダクト１４を備えてい
る。そして，所定温度の熱風が熱風供給ダクト１３から
給気ダンパ１５を経て圧力チャンバ１２に入り，開口溝
１１を通ってチューブ状樹脂搬送室１０内に入り，その
際に未架橋未発泡チューブ状樹脂６’を開口溝１１付近
に浮かせるように流れ，続いて排気ダンパ１６から熱風
排気ダクト１４に流出し，図示せぬ排気ファンを通り外
部排気口へ排出されるか，あるいはバーナー燃焼室へ戻
りそこから再び熱風供給ダクト１３へ送られ循環するよ
うにされている。As shown in FIG. 2, the cross-linking / foaming furnace 5 includes a tubular resin transfer chamber 10 having a V-shaped side wall, an opening groove 11 at the V-shaped lower end of the tubular resin transfer chamber 10,
It has a pressure chamber 12 below it, a hot air supply duct 13 below it, and a hot air exhaust duct 14 above. Then, hot air of a predetermined temperature enters the pressure chamber 12 from the hot air supply duct 13 through the air supply damper 15, enters the tubular resin transfer chamber 10 through the opening groove 11, and at that time, the uncrosslinked unfoamed tubular resin 6 'flows so as to float near the opening groove 11, then flows out of the exhaust damper 16 to the hot air exhaust duct 14, and is discharged to an external exhaust port through an exhaust fan (not shown) or returns to the burner combustion chamber. Is sent to the hot air supply duct 13 again to be circulated.
【００１２】上記の設備による製造工程としては，ま
ず，チューブ押出機１のホッパ２からシリンダ３内に成
形材料を供給し，これを高温・高圧下で加熱溶融させつ
つスクリュー３ａによりニップル・ダイス４ａから押し
出し，チューブ状樹脂６’を得る。成形材料の配合は，
ポリオレフィン系樹脂によるベース樹脂１００重量部に
対して有機発泡剤が１５〜４０重量部の配合とする。こ
の時，チューブ状樹脂６’が架橋しないように，シリン
ダ３の温度はポリオレフィン系樹脂の架橋温度より低く
設定する。ここで，成形材料が効率よく加熱溶融し押し
出されるためには，シリンダ３の設定温度を架橋しない
温度，例えば５０〜１３０℃の間にするのが適切であ
り，かつシリンダ３のホッパ直下部分からヘッド４に向
かけて徐々に前記設定温度まで上げるのが好ましい。In the manufacturing process using the above-mentioned equipment, first, a molding material is supplied from a hopper 2 of a tube extruder 1 into a cylinder 3 and heated and melted at a high temperature and a high pressure while a nipple die 4a is formed by a screw 3a. To obtain a tubular resin 6 '. The compounding of the molding material
The organic foaming agent is blended in an amount of 15 to 40 parts by weight based on 100 parts by weight of the base resin of the polyolefin resin. At this time, the temperature of the cylinder 3 is set lower than the crosslinking temperature of the polyolefin resin so that the tubular resin 6 'is not crosslinked. Here, in order for the molding material to be efficiently heated and melted and extruded, it is appropriate that the set temperature of the cylinder 3 is set to a temperature not cross-linking, for example, 50 to 130 ° C. Preferably, the temperature is gradually raised toward the head 4 to the set temperature.
【００１３】チューブ押出機１によって押し出された成
形材料すなわち未架橋未発泡チューブ状樹脂６’は，架
橋・発泡炉５に入る。この架橋・発泡炉５内で未架橋未
発泡チューブ状樹脂６’は，所定の発泡倍率と発泡径と
を満足する炉内滞留時間をかけて，前述の通り下から吹
き上げる熱風で浮いた状態で搬送される。この架橋・発
泡炉５内を搬送される間に未架橋未発泡チューブ状樹脂
６’は架橋・発泡し，発泡パイプ６となり，架橋・発泡
炉５の直後にある発泡パイプ引取機７によって引き取ら
れる。前述の通り未架橋未発泡チューブ状樹脂６’（な
いし発泡パイプ６）は浮遊して搬送されるから，チュー
ブ押出機１による押出力と，発泡パイプ引取機７による
引取力のみによって搬送される。The molding material extruded by the tube extruder 1, that is, the uncrosslinked unfoamed tubular resin 6 ′ enters the crosslinking and foaming furnace 5. In the cross-linking / foaming furnace 5, the uncross-linked unfoamed tubular resin 6 'is floated by the hot air blown from below as described above, with a residence time in the furnace satisfying a predetermined expansion ratio and a foam diameter. Conveyed. The uncrosslinked unfoamed tubular resin 6 ′ is crosslinked and foamed while being transported in the crosslinking / foaming furnace 5 to form a foamed pipe 6, which is taken up by a foaming pipe take-up machine 7 located immediately after the crosslinking / foaming furnace 5. . As described above, the uncrosslinked unfoamed tubular resin 6 ′ (or foamed pipe 6) is transported in a floating state, and therefore is transported only by the pushing force of the tube extruder 1 and the pulling force of the foamed pipe pulling machine 7.
【００１４】ここで使用する架橋・発泡炉５は，炉長が
２〜３０メートル程度が好ましく，長さ方向で１〜１０
ゾーンに区割りし，各ゾーン毎に温度および風速（差
圧）の調整ができる構造であれば，一層効果的である。
また，架橋・発泡炉５における諸条件として，温度は成
形材料の架橋温度と発泡温度を考慮して，ほぼ１９０〜
２５０℃の範囲で調整し，吹き上げる熱風の速度は炉上
部と炉下部との差圧換算で５〜６０ｍｍＡｑの範囲であ
れば，チューブ状樹脂６’および発泡パイプ６とも適切
に浮いた状態を保つことができる。ただし，温度，風速
とも未架橋未発泡チューブ状樹脂６’のサイズ，比重に
合わせて調整する。The cross-linking / foaming furnace 5 used here preferably has a furnace length of about 2 to 30 meters, and has a length of 1 to 10 meters in the longitudinal direction.
It is more effective if the structure is divided into zones and the temperature and wind speed (differential pressure) can be adjusted for each zone.
In addition, as the conditions in the crosslinking / foaming furnace 5, the temperature is set to approximately 190 to 90 in consideration of the crosslinking temperature and the foaming temperature of the molding material.
Adjust the temperature in the range of 250 ° C, and if the speed of the hot air to blow up is in the range of 5 to 60 mmAq in terms of the differential pressure between the furnace upper part and the furnace lower part, both the tubular resin 6 ′ and the foamed pipe 6 are kept in an appropriately floating state. be able to. However, both the temperature and the wind speed are adjusted according to the size and specific gravity of the uncrosslinked unfoamed tubular resin 6 '.
【００１５】なお，チューブ状樹脂６’が架橋・発泡炉
５内で架橋・発泡し２０〜４０倍の発泡倍率を達成する
ためには，サイズ，配合比の違いにより３〜２０分程度
の炉内滞留時間を要する。この時間と架橋・発泡炉５の
長さを考慮して線速を決定するとよい。架橋・発泡炉５
内で所定の発泡倍率を満足する滞留時間を経た発泡パイ
プ６のチューブ状樹脂６’に対する長手方向の伸びは，
サイズ等により異なるが１．５〜３．５倍程度であるか
ら，これを自然発泡による伸び率と考えて，押出線速に
対する引取線速比率として設定すれば，伸びた分だけ引
き取るという具合で無理なく発泡パイプを引き取ること
ができる。なお，この架橋・発泡炉５は，前述の通り内
部にコンベヤ等の搬送媒体がないため，炉のサイズによ
っては，複数のチューブ押出機１および発泡パイプ引取
機７を並列配置して，パスラインを複数ライン設けるこ
とができる。In order to achieve the expansion ratio of 20 to 40 times by cross-linking and foaming of the tubular resin 6 'in the cross-linking / foaming furnace 5, a furnace of about 3 to 20 minutes is required depending on the size and the mixing ratio. It requires internal residence time. The linear velocity may be determined in consideration of this time and the length of the crosslinking / foaming furnace 5. Crosslinking and foaming furnace 5
The elongation of the foamed pipe 6 in the longitudinal direction with respect to the tubular resin 6 ′ after a residence time satisfying a predetermined foaming ratio is within:
Although it depends on the size, etc., it is about 1.5 to 3.5 times, so if this is considered as the elongation ratio due to natural foaming and set as the ratio of the drawing linear speed to the extrusion linear speed, it will take up only the stretched portion. The foam pipe can be easily taken. Since the cross-linking / foaming furnace 5 has no conveyor medium such as a conveyor as described above, depending on the size of the furnace, a plurality of tube extruders 1 and a foaming pipe take-off machine 7 are arranged in parallel to form a pass line. Can be provided on a plurality of lines.
【００１６】次に，具体的配合の例を述べる。Next, a specific example of the composition will be described.
【表１】 表１の配合は難燃性のポリオレフィン系樹脂組成物の場
合であり，ベース樹脂としてＥＶＡすなわちエチレン・
酢酸ビニル共重合体（酢酸ビニル成分＝３６％，ＭＩ
（メルトインデックス）＝２）を１００重量部，難燃剤
として水酸化マグネシゥム（Ｍｇ（ＯＨ）2 ）を１００
重量部，架橋剤としてＤＣＰすなわちジクミルパーオキ
サイドを２重量部，発泡剤としてアゾジカルボンアミド
（ＡＤＣＡ）を３０重量部の割合で配合している。有機
発泡剤としては，アゾジカルボンアミド（ＡＣＤＡ），
ジニトロソベンタメチレンテトラミン（ＤＰＴ），Ｐ−
Ｐ’−オキシビス（ベンゼンスルホニルヒドラジッド）
（ＯＢＳＨ），バリウムアゾジカルボキシレート等があ
る。[Table 1] The formulation in Table 1 is for a flame-retardant polyolefin resin composition, and EVA, ie, ethylene.
Vinyl acetate copolymer (vinyl acetate component = 36%, MI
(Melt index) = 2) and 100 parts by weight of magnesium hydroxide (Mg (OH) 2 ) as a flame retardant.
Parts by weight, 2 parts by weight of DCP, ie, dicumyl peroxide as a crosslinking agent, and 30 parts by weight of azodicarbonamide (ADCA) as a foaming agent. As organic foaming agents, azodicarbonamide (ACDA),
Dinitrosoventamethylenetetramine (DPT), P-
P'-oxybis (benzenesulfonyl hydrazide)
(OBSH), barium azodicarboxylate and the like.
【表２】 表２は非難燃性のポリオレフィン系樹脂組成物の場合で
あり，ベース樹脂としてＬＤＰＥすなわち低密度ポリエ
チレン（ＭＩ＝２）を１００重量部，架橋剤としてＤＣ
Ｐを１重量部，発泡剤としてアゾジカルボンアミドを１
８重量部の割合で配合している。[Table 2] Table 2 shows the case of a non-flame-retardant polyolefin resin composition, in which 100 parts by weight of LDPE, that is, low-density polyethylene (MI = 2) was used as a base resin, and DC was used as a crosslinking agent.
1 part by weight of P, 1 part of azodicarbonamide as a foaming agent
It is blended at a ratio of 8 parts by weight.
【００１７】上記２種の配合のポリオレフィン系樹脂組
成物を成形材料として，従来のシート押出・発泡方式，
および本発明のチューブ押出・発泡方式でそれぞれ発泡
パイプを製造したが，両者を比較すると次の通りであ
る。なお，製造した発泡パイプのサイズは内径８ｍｍ
φ，肉厚８ｍｍである。The polyolefin-based resin composition of the above two types is used as a molding material, and a conventional sheet extrusion / foaming method is used.
A foamed pipe was manufactured by the tube extrusion / foaming method of the present invention, and the two are compared as follows. The size of the manufactured foam pipe is 8mm inside diameter.
φ, wall thickness 8 mm.
【００１８】製造工程については，シート押出・発泡方
式では，従来例で述べたように９工程からなり，タンデ
ム工程の単位でいえば３工程を必要とするのに対して，
本発明のチューブ押出・発泡方式では，３工程からな
り，タンデム工程の単位でいえば１工程で済む。また，
必要作業人員についても，シート押出・発泡方式では２
名を必要とするのに対して，チューブ押出・発泡方式で
は１名で済む。このように，有機発泡剤を用いるシート
押出・発泡方式では工程間で仕掛かり半製品の運搬に時
間と人員を費やすことに対して，後者は材料投入から製
品完成までの作業者１人当たりの工数が前者の３分の１
で済み，格段に作業効率の面で優位である。また，製造
に要する時間については，例えば発泡パイプを１０００
メートル製造するために必要な時間で比較すると，チュ
ーブ押出・発泡方式による場合の所要時間は，シート押
出・発泡方式による場合の所要時間の約８分の５であ
る。なお，前記の比較した所要時間は，発泡パイプ引取
りまでを含めた全工程に要する時間である。また，成形
材料の歩留りについては，チューブ押出・発泡方式によ
る場合に発生するロスは，シート押出・発泡方式による
場合に発生するロスの約２３分の１である。発泡倍率に
ついては，いずれの場合も３０倍の発泡倍率が得られ
た。このように，チューブ押出・発泡方式に有機発泡剤
を用いても発泡倍率低下の問題は生じないし，また，難
燃剤を配合しても発泡倍率低下の問題は生じない。ま
た，発泡パイプの性能に関しては，難燃，非難燃のいず
れの成形材料でも差異はなく，耐熱特性を持たせるため
の問題は全てクリアできている。また，製造工程自体に
おいても，難燃，非難燃のいずれの成形材料でも，特別
な問題は何も生じない。さらに，外観上でも，シート押
出・発泡方式では熱融着跡が残るのに対して，チューブ
押出・発泡方式ではそれがなく，表面が美しいものであ
るから，商品価値についても優位である。In the sheet extrusion / foaming method, the sheet extrusion / foaming method comprises nine steps as described in the conventional example, and requires three steps in the unit of the tandem step.
The tube extrusion / foaming method of the present invention comprises three steps, and only one step is required in the unit of a tandem step. Also,
The required workforce is also 2 in the sheet extrusion / foaming method.
While the name is required, the tube extrusion / foaming method requires only one person. As described above, the sheet extrusion / foaming method using an organic foaming agent consumes time and manpower to transport semi-finished products between processes, whereas the latter involves man-hours per worker from material input to product completion. Is one-third of the former
It is much better in terms of work efficiency. Regarding the time required for the production, for example, 1000
Comparing the time required for metric production, the time required for the tube extrusion / foaming method is about 5/8 of the time required for the sheet extrusion / foaming method. The time required for comparison is the time required for all the steps including the process of taking up the foam pipe. As for the yield of the molding material, the loss generated by the tube extrusion / foaming method is about 1/23 of the loss generated by the sheet extrusion / foaming method. Regarding the expansion ratio, a expansion ratio of 30 times was obtained in each case. As described above, even if an organic foaming agent is used in the tube extrusion / foaming method, the problem of a decrease in the expansion ratio does not occur, and even if a flame retardant is blended, the problem of a decrease in the expansion ratio does not occur. Further, regarding the performance of the foamed pipe, there is no difference between the flame-retardant and non-flame-retardant molding materials, and all the problems for providing the heat-resistant properties have been cleared. Also, in the manufacturing process itself, there is no particular problem with any of the flame-retardant and non-flame-retardant molding materials. Furthermore, the appearance of heat fusion remains in the sheet extrusion / foaming method, while the tube extrusion / foaming method does not have such a beautiful appearance.
【００１９】なお，本発明において上述した配合のポリ
オレフィン系樹脂組成物にさらに適宜の添加物を配合す
ることは当然考えられる。また，未架橋未発泡チューブ
状樹脂を浮遊搬送するための架橋・発泡炉の内部構造
は，図示例に限定されない。要するに，吹き上げる熱風
により，未架橋未発泡チューブ状樹脂を架橋・発泡炉の
内壁に接触しない（ないしはごく軽くしか接触しない）
程度に浮かせることができればよい。In the present invention, it is naturally conceivable to further add an appropriate additive to the polyolefin resin composition having the above-mentioned composition. The internal structure of the crosslinking / foaming furnace for floatingly transporting the uncrosslinked unfoamed tubular resin is not limited to the illustrated example. In short, the uncrosslinked unfoamed tubular resin does not come into contact with the inner wall of the crosslinking / foaming furnace (or only very lightly) due to the blowing hot air.
It just needs to be able to float to the extent.
【００２０】[0020]
【発明の効果】本発明によれば，チューブ押出・発泡方
式を採用しているので，シート押出・発泡方式と比べ
て，材料投入から製品完成までの工程数，作業人員，所
要時間を大幅に削減することができ，生産性が大幅に向
上する。また，全工程について歩留りを改善することが
できる。また，製品パイプの外面に熱融着跡はなく，外
観が良好である。According to the present invention, since the tube extrusion / foaming method is employed, the number of steps, labor and time required from material input to product completion are significantly reduced as compared with the sheet extrusion / foaming method. Can be reduced and productivity is greatly improved. Further, the yield can be improved in all the steps. Also, there is no trace of heat fusion on the outer surface of the product pipe, and the appearance is good.
【００２１】発泡剤として有機発泡剤を用いているの
で，従来のフロンやブタン等の発泡剤と異なり，有害物
が発生しない。Since an organic foaming agent is used as a foaming agent, no harmful substances are generated unlike conventional foaming agents such as chlorofluorocarbon and butane.
【００２２】有機発泡剤を用いたことに伴って未架橋未
発泡チューブ状樹脂で架橋・発泡炉内を搬送させる必要
が生じるが，架橋・発泡炉内の未架橋未発泡チューブ状
樹脂は下から吹き上げる熱風により浮遊した状態で搬送
されるので，その未架橋未発泡チューブ状樹脂の外面が
変形することはなく，均等に発泡するので，良好な外観
の発泡パイプが得られる。With the use of the organic foaming agent, it is necessary to convey the non-crosslinked unfoamed tubular resin with the uncrosslinked unfoamed tubular resin. Since the non-crosslinked unfoamed tubular resin is conveyed in a floating state by the blown-up hot air, the outer surface of the non-crosslinked unfoamed tubular resin is not deformed and is evenly foamed, so that a foamed pipe having a good appearance can be obtained.
【００２３】請求項２によれば，発泡パイプに難燃性を
与える課題に容易に応えることができる。According to the second aspect, the problem of imparting flame retardancy to the foamed pipe can be easily met.
【図１】本発明の一実施例のポリオレフィン系樹脂発泡
パイプの製造方法を採用した発泡パイプ製造装置の概略
図である。FIG. 1 is a schematic view of a foam pipe manufacturing apparatus employing a method for manufacturing a polyolefin resin foam pipe according to one embodiment of the present invention.
【図２】図１における架橋・発泡炉の内部構造を示す断
面図である。FIG. 2 is a sectional view showing the internal structure of the crosslinking / foaming furnace in FIG.
１ チューブ押出機 ３ シリンダ ３ａ スクリュー ４ ヘッド ４ａ ニップル・ダイス ５ 架橋・発泡炉 ６ 発泡パイプ ６’ 未架橋未発泡チューブ状樹脂 ７ 発泡パイプ引取機 DESCRIPTION OF SYMBOLS 1 Tube extruder 3 Cylinder 3a Screw 4 Head 4a Nipple dice 5 Crosslinking / foaming furnace 6 Foaming pipe 6 'Uncrosslinked unfoamed tubular resin 7 Foaming pipe take-off machine
───────────────────────────────────────────────────── フロントページの続き (51)Int.Cl.7 識別記号 ＦＩ Ｂ２９Ｋ 105:24 Ｂ２９Ｋ 105:24 Ｂ２９Ｌ 23:00 Ｂ２９Ｌ 23:00 (72)発明者 渡邊 知久 東京都江東区木場１丁目５番１号 株式 会社フジクラ内 (72)発明者 小林 宣夫 静岡県沼津市双葉町９番１号 株式会社 フジクラ沼津工場内 (72)発明者 水野 康彦 東京都江東区木場１丁目５番１号 株式 会社フジクラ内 (56)参考文献 特開 昭53−52577（ＪＰ，Ａ) 特開 昭60−36119（ＪＰ，Ａ) 特開 昭58−1531（ＪＰ，Ａ) 特開 平４−126733（ＪＰ，Ａ) 特開 平５−116206（ＪＰ，Ａ) (58)調査した分野(Int.Cl.7，ＤＢ名) B29C 47/00 - 47/96 B29C 35/06 ────────────────────────────────────────────────── ─── Continued on the front page (51) Int.Cl. 7 Identification code FI B29K 105: 24 B29K 105: 24 B29L 23:00 B29L 23:00 (72) Inventor Tomohisa Watanabe 1-5 Kiba, Koto-ku, Tokyo No. 1 Inside Fujikura Co., Ltd. (72) Inventor Nobuo Kobayashi 9-1, Futaba-cho, Numazu City, Shizuoka Prefecture Inside Fujikura Numazu Plant (72) Inventor Yasuhiko Mizuno 1-5-1, Kiba, Koto-ku, Tokyo Fujikura Co., Ltd. (56) References JP-A-53-52577 (JP, A) JP-A-60-36119 (JP, A) JP-A-58-1531 (JP, A) JP-A-4-126733 (JP, A) JP-A-5-116206 (JP, A) (58) Fields investigated (Int. Cl. 7 , DB name) B29C 47/00-47/96 B29C 35/06
Claims (2)
合してなるポリオレフィン系樹脂組成物をチューブ押出
機に供給し，このチューブ押出機から押し出された未架
橋未発泡チューブ状樹脂を架橋・発泡炉内で下側から吹
き上げる熱風で浮かせながら搬送し，この熱風により架
橋・発泡させて発泡パイプを得ることを特徴とするポリ
オレフィン系樹脂発泡パイプの製造方法。1. A polyolefin-based resin composition containing at least a crosslinking agent and an organic foaming agent is supplied to a tube extruder, and an uncrosslinked unfoamed tubular resin extruded from the tube extruder is crosslinked and foamed in a furnace. A method for producing a polyolefin resin foam pipe, characterized in that the foam is conveyed while being floated by hot air blown from below in the inside, and is crosslinked and foamed by the hot air to obtain a foam pipe.
剤を含有することを特徴とする請求項１記載のポリオレ
フィン系樹脂発泡パイプの製造方法。2. The method for producing a polyolefin resin foam pipe according to claim 1, wherein the polyolefin resin composition contains a flame retardant.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP16285795A JP3273487B2 (en) | 1995-06-06 | 1995-06-06 | Method for producing polyolefin resin foam pipe |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP16285795A JP3273487B2 (en) | 1995-06-06 | 1995-06-06 | Method for producing polyolefin resin foam pipe |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPH08332666A JPH08332666A (en) | 1996-12-17 |
| JP3273487B2 true JP3273487B2 (en) | 2002-04-08 |
Family
ID=15762575
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP16285795A Expired - Fee Related JP3273487B2 (en) | 1995-06-06 | 1995-06-06 | Method for producing polyolefin resin foam pipe |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JP3273487B2 (en) |
Family Cites Families (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS599336B2 (en) * | 1976-10-25 | 1984-03-01 | 古河電気工業株式会社 | Method for producing polyolefin foam |
| JPS581531A (en) * | 1981-06-28 | 1983-01-06 | Dainichi Nippon Cables Ltd | Method for continuously preparing crosslinked foamed polyolefin tubular body |
| JPS6036119A (en) * | 1983-08-09 | 1985-02-25 | Sumitomo Electric Ind Ltd | Cover cooler for filamentous body |
| JPH04126733A (en) * | 1990-09-17 | 1992-04-27 | Furukawa Electric Co Ltd:The | Production of crosslinked and expanded material |
| JPH05116206A (en) * | 1991-10-29 | 1993-05-14 | Sekisui Chem Co Ltd | Production of extruded foam and equipment |
-
1995
- 1995-06-06 JP JP16285795A patent/JP3273487B2/en not_active Expired - Fee Related
Also Published As
| Publication number | Publication date |
|---|---|
| JPH08332666A (en) | 1996-12-17 |
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