JPH09241437A - Polyethylene composition for applying steel pipe - Google Patents
Polyethylene composition for applying steel pipeInfo
- Publication number
- JPH09241437A JPH09241437A JP5159196A JP5159196A JPH09241437A JP H09241437 A JPH09241437 A JP H09241437A JP 5159196 A JP5159196 A JP 5159196A JP 5159196 A JP5159196 A JP 5159196A JP H09241437 A JPH09241437 A JP H09241437A
- Authority
- JP
- Japan
- Prior art keywords
- density polyethylene
- polyethylene
- steel pipe
- linear low
- escr
- 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
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- Compositions Of Macromolecular Compounds (AREA)
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Abstract
Description
【０００１】[0001]
【発明の属する技術分野】本発明は、特定の線状低密度
ポリエチレン及び同高密度ポリエチレンを特定比率で含
有してなる、低温物性及び耐ストレスクラック性（ＥＳ
ＣＲ）に優れ、かつ高温での針入度の改良された鋼管被
覆用ポリエチレン組成物に関する。TECHNICAL FIELD The present invention relates to low-temperature physical properties and stress crack resistance (ES) containing a specific linear low-density polyethylene and the same high-density polyethylene in a specific ratio.
The present invention relates to a polyethylene composition for coating steel pipes, which has excellent CR) and improved penetration at high temperatures.
【０００２】[0002]
【従来の技術】従来、石油、天然ガス等の天然資源を輸
送したり、または、通信用或いは送電用のケーブルを通
したりするためのパイプラインを形成する鋼管は、地球
上のあらゆる場所（例えば、地上、地中、河川、沼地、
海中、また寒冷地方から熱帯地方など）に敷設又は埋設
される可能性があり、数十年に及ぶ長期間の使用に耐え
ることが求められている。このため、この種の鋼管は、
地球上の予想され得る気象条件、及び、敷設又は埋設条
件に適応できるものでなければならず、鋼管の耐久性、
特に鋼管を構成する鋼材の腐食性が大きな問題であっ
た。したがって、この鋼材の腐食抑制のためにパイプラ
イン用鋼管の防蝕被覆として、近年、ポリエチレンで鋼
管を被覆する方法が採られている。2. Description of the Related Art Conventionally, a steel pipe forming a pipeline for transporting natural resources such as oil and natural gas, or for passing a cable for communication or power transmission has been used anywhere on the earth (for example, , Ground, underground, river, swamp,
It may be laid or buried in the sea or in cold regions to tropical regions, etc., and is required to withstand long-term use for several decades. Therefore, this type of steel pipe
Durability of the steel pipe, which must be able to adapt to the possible weather conditions on the earth and the laying or burial conditions,
Particularly, the corrosiveness of the steel material forming the steel pipe has been a serious problem. Therefore, in order to suppress the corrosion of the steel material, a method of coating the steel pipe with polyethylene has been adopted in recent years as an anticorrosion coating for the pipeline steel pipe.
【０００３】上記の通り、パイプラインは寒冷地方から
熱帯地方の極めて広い範囲にわたる過酷な気象条件に曝
され、また、パイプライン操業後は温度が１００℃近く
まで上昇することから、鋼管被覆用ポリエチレンは低温
での耐衝撃性、可撓性の外に高温での耐熱老化性、ＥＳ
ＣＲ、耐針入性等、広い温度範囲での安定な品質が要求
される。寒冷地用の鋼管被覆に用いられるポリエチレン
としては、高圧法ポリエチレン、特にエチレン−酢酸ビ
ニル共重合体樹脂（ＥＶＡ）が知られている。しかしな
がら、ＥＶＡはコストが高く、かつ水に接触すると酸を
発生させるという問題点がある。また、高圧法ポリエチ
レンの代わりに中・低圧法ポリエチレン、特に中・高密
度ポリエチレンを使用した場合には、ＥＳＣＲや低温耐
衝撃性の点で劣った物性しか得られず、かつ引張弾性率
が高いことによる残留内部応力が大きいため寒冷地用に
は不向きである。本発明者等は、先に、寒冷地用の鋼管
被覆に用いられ得るポリエチレンの問題点を解決すべ
く、特定の物性（メルトインデックス、流動比、密度及
び低温での引張破断点伸度）を有する線状低密度ポリエ
チレン組成物を提案した（特願平７−６２１６４号公報
参照）。しかしながら、このもので被覆した鋼管のパイ
プラインは操業温度が１００℃近くまで上昇する状況下
では被覆ポリエチレンが過度に軟化して安定運転を損な
ってしまう可能性があり、使用環境を選ばなければなら
ないものであるため、さらに改良が必要であった。As described above, the pipeline is exposed to severe weather conditions over a wide range from cold regions to tropical regions, and the temperature rises to near 100 ° C. after the pipeline is operated. Is impact resistance at low temperature, heat resistance aging at high temperature in addition to flexibility, ES
Stable qualities in a wide temperature range such as CR and penetration resistance are required. As polyethylene used for coating steel pipes in cold regions, high-pressure polyethylene, particularly ethylene-vinyl acetate copolymer resin (EVA) is known. However, EVA has the problems of high cost and generation of acid when it comes into contact with water. In addition, when medium / low pressure polyethylene, especially medium / high density polyethylene, is used instead of high pressure polyethylene, only poor physical properties are obtained in terms of ESCR and low temperature impact resistance, and the tensile modulus is high. Due to the large residual internal stress, it is not suitable for cold regions. The present inventors previously set specific physical properties (melt index, flow ratio, density and tensile elongation at low temperature) in order to solve the problems of polyethylene that can be used for coating steel pipes for cold regions. A linear low density polyethylene composition having the same was proposed (see Japanese Patent Application No. 7-62164). However, in a steel pipe pipeline coated with this product, there is a possibility that the coated polyethylene may be excessively softened and the stable operation may be impaired under the condition that the operating temperature rises up to about 100 ° C. Therefore, further improvement was necessary.
【０００４】[0004]
【発明が解決しようとする課題】本発明の目的は、かか
る従来技術の欠点を改良して、低温物性及びＥＳＣＲに
優れ、かつ高温での針入度の改良された鋼管被覆用ポリ
エチレン組成物を提供することにある。SUMMARY OF THE INVENTION An object of the present invention is to solve the above-mentioned drawbacks of the prior art by providing a polyethylene composition for coating a steel pipe, which has excellent low temperature properties and ESCR and improved penetration at high temperatures. To provide.
【０００５】[0005]
【課題を解決するための手段】本発明者等は、上記課題
を解決するために鋭意検討の結果、特定の物性を有する
線状低密度ポリエチレンを主体とし、これと同高密度ポ
リエチレンを特定比率で含有してなるポリエチレン組成
物を鋼管被覆材に使用することにより上記目的が達成さ
れることを見出して本発明を完成した。Means for Solving the Problems As a result of intensive studies to solve the above-mentioned problems, the inventors of the present invention have mainly made a linear low-density polyethylene having specific physical properties, and have the same high-density polyethylene as the specific ratio. The present invention has been completed by discovering that the above object can be achieved by using the polyethylene composition containing in 1) as a steel pipe coating material.
【０００６】すなわち、本発明は、メルトインデックス
（ＭＩ）０．１〜１．５ｇ／１０分、ＥＳＣＲ１０００
時間以上、かつ、−４５℃での引張破断点伸度２００％
以上の線状低密度ポリエチレン６０〜９０重量％及びメ
ルトインデックス１ｇ／１０分以下、流動比５０以上、
密度０．９４ｇ／ｃｍ3 以上の高密度ポリエチレン１０
〜４０重量％を含有してなることを特徴とする鋼管被覆
用ポリエチレン組成物である。That is, according to the present invention, the melt index (MI) is 0.1 to 1.5 g / 10 minutes, and ESCR1000 is used.
Elongation at tensile breaking point of 200% or more at -45 ° C for more than an hour
The above linear low density polyethylene 60 to 90% by weight, melt index 1 g / 10 minutes or less, flow ratio 50 or more,
High-density polyethylene 10 with a density of 0.94 g / cm 3 or more
The polyethylene composition for coating a steel pipe is characterized by containing 40 to 40% by weight.
【０００７】[0007]
【発明の実施の形態】本発明で使用する線状低密度ポリ
エチレンは、エチレンを主成分とするエチレンと他のα
−オレフィンとの共重合体であり、従来の高圧法により
製造される低密度ポリエチレンとは異なる。ここで、α
−オレフィンとしてはプロピレン、ブテン、ペンテン、
ヘキセン、オクテン、デセン、３−メチルブテン、４−
メチルペンテン等（好ましくは炭素数４〜１２のα−オ
レフィン）を使用でき、その共重合体中の含有量は４〜
１７重量％程度、好ましくは５〜１５重量％程度であ
る。この共重合体は、中低圧法高密度ポリエチレンの製
造に用いられるチーグラー型触媒又はフィリップス型触
媒を使用して製造されるものであり、従来の高密度ポリ
エチレンを共重合成分により短い分岐構造を有する構造
とし、この短分岐構造を利用して（即ち、共重合成分の
種類と含量を調整して）密度を適当に低下させたもので
あって、従来の高圧法低密度ポリエチレンより直鎖性が
あり、高密度ポリエチレンより分岐が多い構造のポリエ
チレンである。この線状低密度ポリエチレンは、流動床
反応器、攪拌床反応器、管型反応器等を用いる気相重合
法の製造プロセスを適用し、例えば特開昭５４−１４８
０９３、同５４−１５４４８８号公報等に記載されてい
る方法（流動床反応器を使用した気相重合法）に基づい
て製造することができる。なお、線状低密度ポリエチレ
ンには、本発明の効果を著しく損なわない範囲において
他の重合性単量体、例えば不飽和カルボン酸又はその誘
導体（アクリル酸、アクリル酸メチル、アクリル酸エチ
ル、無水マレイン酸等）、ビニルエステル（酢酸ビニ
ル、酪酸ビニル等）、不飽和芳香族単量体（スチレン、
α−メチルスチレン等）など、をブロック、ランダム、
グラフト等の共重合の形態で含有していても構わない。BEST MODE FOR CARRYING OUT THE INVENTION The linear low-density polyethylene used in the present invention is composed mainly of ethylene and other α
It is a copolymer with olefins and is different from low density polyethylene produced by conventional high pressure processes. Where α
-As olefins propylene, butene, pentene,
Hexene, octene, decene, 3-methylbutene, 4-
Methylpentene or the like (preferably an α-olefin having 4 to 12 carbon atoms) can be used, and the content in the copolymer is 4 to
It is about 17% by weight, preferably about 5 to 15% by weight. This copolymer is produced by using a Ziegler-type catalyst or Phillips-type catalyst used in the production of medium- and low-pressure method high-density polyethylene, and has a short branched structure in which conventional high-density polyethylene is copolymerized. The structure has a structure in which the density is appropriately reduced by utilizing this short branched structure (that is, by adjusting the type and content of the copolymerization component), and the linearity is lower than that of the conventional high pressure low density polyethylene. It is a polyethylene having a structure with more branches than high-density polyethylene. This linear low density polyethylene is produced by applying a production process of a gas phase polymerization method using a fluidized bed reactor, a stirred bed reactor, a tubular reactor, etc.
093, 54-154488 and the like (gas phase polymerization method using a fluidized bed reactor). In addition, the linear low-density polyethylene includes other polymerizable monomers such as unsaturated carboxylic acid or its derivative (acrylic acid, methyl acrylate, ethyl acrylate, maleic anhydride) within a range that does not significantly impair the effects of the present invention. Acid, etc.), vinyl ester (vinyl acetate, vinyl butyrate, etc.), unsaturated aromatic monomer (styrene,
α-methylstyrene, etc.), etc.
It may be contained in the form of copolymerization such as grafting.
【０００８】この様な方法によって製造される線状低密
度ポリエチレンの内、そのＭＩが０．１〜１．５ｇ／１
０分、好ましくは０．２〜０．８ｇ／１０分、ＥＳＣＲ
が１０００時間以上、好ましくは３０００時間以上、か
つ、−４５℃での引張破断点伸度が２００％以上、好ま
しくは４００％以上の線状低密度ポリエチレンが本発明
において使用され得る。また、低温での耐衝撃性、残留
内部応力の点から、該線状低密度ポリエチレンの好適な
密度は０．９１〜０．９３ｇ／ｃｍ3 、特に好ましくは
０．９１５〜０．９２５ｇ／ｃｍ3 である。さらに、成
形時の押出性、ＥＳＣＲの点から、該線状低密度ポリエ
チレンの好適な流動比は４５以上（上限は１５０程
度）、特に好ましくは５０〜１００である。Among the linear low density polyethylene produced by such a method, its MI is 0.1 to 1.5 g / 1.
0 minutes, preferably 0.2-0.8 g / 10 minutes, ESCR
Is 1000 hours or more, preferably 3000 hours or more, and a linear low density polyethylene having a tensile elongation at break at -45 ° C of 200% or more, preferably 400% or more can be used in the present invention. From the viewpoint of impact resistance at low temperature and residual internal stress, the linear low density polyethylene preferably has a density of 0.91 to 0.93 g / cm 3 , and particularly preferably 0.915 to 0.925 g / cm 3 . Is 3 . Further, in view of extrudability during molding and ESCR, a suitable flow ratio of the linear low density polyethylene is 45 or more (upper limit is about 150), particularly preferably 50 to 100.
【０００９】ＭＩが低過ぎると成形時の押出性が劣り、
他方高過ぎると引張試験等での強度、ＥＳＣＲが悪化す
る。ここで、ＭＩはＪＩＳ Ｋ６７６０に準拠して１９
０℃で測定した値であり、また、引張破断点伸度はＪＩ
Ｓ Ｋ７１１３に準拠して−４５℃においてプレス試片
にて測定した値であり、ＥＳＣＲはＪＩＳ Ｋ６７６０
に準拠して測定した値である。なお、密度はＪＩＳ Ｋ
６７６０に準拠して測定した値であり、流動比はＭＩ測
定器を用いて測定した剪断力１０6 ｄｙｎｅ／ｃｍ
2 （荷重１１１３１ｇ）での押出量（ｇ／１０分）と剪
断力１０5 ｄｙｎｅ／ｃｍ2 （荷重１１１３ｇ）での押
出量（ｇ／１０分）の比である。流動比は、樹脂の分子
量分布の目安であって、その値が小さければ分子量分布
は狭く、逆に大きければ分子量分布は広いことを表す。If the MI is too low, the extrudability during molding is poor,
On the other hand, if it is too high, the strength in the tensile test and the ESCR deteriorate. Here, MI is 19 according to JIS K6760.
It is the value measured at 0 ° C., and the elongation at break at JI is JI.
It is a value measured with a press sample at -45 ° C in accordance with SK7113, and ESCR is JIS K6760.
It is a value measured in accordance with. The density is JIS K
It is a value measured according to 6760, and the flow ratio is a shearing force of 10 6 dyne / cm measured using an MI measuring instrument.
2 is the ratio of the extrusion rate (g / 10 min) at 2 (load 11131 g) and the extrusion rate (g / 10 min) at shear force of 10 5 dyne / cm 2 (load 1113 g). The flow ratio is a measure of the molecular weight distribution of the resin, and if the value is small, the molecular weight distribution is narrow, and conversely if it is large, the molecular weight distribution is wide.
【００１０】また、本発明で使用する高密度ポリエチレ
ンは、上記線状低密度ポリエチレン同様、中低圧法プロ
セスによりエチレンの単独重合体又はエチレンと若干の
α−オレフィンとの共重合体として製造されるものであ
る。高密度ポリエチレンの内、そのＭＩが１ｇ／１０分
以下、好ましくは０．０１〜１ｇ／１０分、流動比が５
０以上（上限は２００程度）、好ましくは５０〜１５
０、密度が０．９４ｇ／ｃｍ3 以上、ＥＳＣＲの点から
好ましくは０．９４〜０．９６ｇ／ｃｍ3 の高密度ポリ
エチレンが本発明において使用され得る。これら物性の
測定法は上記線状低密度ポリエチレンと同様である。The high-density polyethylene used in the present invention is produced as a homopolymer of ethylene or a copolymer of ethylene and a small amount of α-olefin, by the medium-low pressure process, like the linear low-density polyethylene. It is a thing. Among the high-density polyethylene, its MI is 1 g / 10 minutes or less, preferably 0.01 to 1 g / 10 minutes, and the flow ratio is 5.
0 or more (upper limit is about 200), preferably 50 to 15
0, density of 0.94 g / cm 3 or more, preferably in terms of ESCR high density polyethylene 0.94~0.96g / cm 3 may be used in the present invention. The measuring method of these physical properties is the same as that of the linear low density polyethylene.
【００１１】ＭＩが低過ぎると成形時の押出性が劣り、
他方高過ぎると引張試験等での強度、ＥＳＣＲが悪化す
る。また、流動比が低過ぎると成形時の押出性、ＥＳＣ
Ｒが悪化する。さらに、密度が低過ぎると高温での針入
度が劣る。If the MI is too low, the extrudability during molding is poor,
On the other hand, if it is too high, the strength in the tensile test and the ESCR deteriorate. Also, if the flow ratio is too low, extrudability during molding, ESC
R deteriorates. Further, if the density is too low, the penetration at high temperature will be poor.
【００１２】これらの線状低密度ポリエチレン及び高密
度ポリエチレンの配合比は、線状低密度ポリエチレン６
０〜９０重量％、好ましくは６５〜８５重量％及び高密
度ポリエチレン１０〜４０重量％好ましくは１５〜３５
重量％の範囲内である。線状低密度ポリエチレンが少な
過ぎると低温物性やＥＳＣＲが劣り、他方、多過ぎると
高温での耐針入性が劣り好ましくない。The mixing ratio of these linear low-density polyethylene and high-density polyethylene is such that the linear low-density polyethylene 6
0-90% by weight, preferably 65-85% by weight and high-density polyethylene 10-40% by weight, preferably 15-35%
% By weight. If the amount of linear low-density polyethylene is too small, the low-temperature physical properties and ESCR are poor, while if it is too large, the needle penetration resistance at high temperatures is poor.
【００１３】本発明においては、上記の必須成分のほか
に所望により任意の成分を、本発明の効果を著しく損な
わない範囲で配合させることができる。任意成分として
は、ポリエチレンに従来配合される添加剤、例えば他の
熱安定剤、紫外線吸収剤、光安定剤、酸化防止剤、帯電
防止剤、滑剤、中和剤、防錆剤のほか、充填材、難燃
剤、顔料、滑剤、中和剤、防錆剤、導電剤等々を挙げる
ことができる。特に、紫外線防止剤としてカーボンブラ
ックを０．１〜４重量％、特に０．５〜３重量％配合す
るのは好適である。また、酸化防止剤としてフェノール
系酸化防止剤、硫黄系酸化防止剤、燐系酸化防止剤等を
０．０１〜２重量％添加することも好適であり、滑剤と
して金属石鹸類や中和剤を０．０１〜０．２重量％配合
することも構わない。In the present invention, in addition to the above-mentioned essential components, if desired, optional components can be blended within a range that does not significantly impair the effects of the present invention. As an optional component, additives conventionally added to polyethylene, such as other heat stabilizers, ultraviolet absorbers, light stabilizers, antioxidants, antistatic agents, lubricants, neutralizing agents, rust preventives, and filling Materials, flame retardants, pigments, lubricants, neutralizing agents, rust preventives, conductive agents and the like. In particular, it is preferable to add 0.1 to 4% by weight, especially 0.5 to 3% by weight, of carbon black as an ultraviolet ray inhibitor. It is also preferable to add 0.01 to 2% by weight of a phenol-based antioxidant, a sulfur-based antioxidant, a phosphorus-based antioxidant or the like as an antioxidant, and a metal soap or a neutralizer as a lubricant. It is also possible to add 0.01 to 0.2% by weight.
【００１４】上記の必須成分及び場合により任意成分を
配合し、適当な通常の混合・混練機にて混合・混練する
ことによりポリエチレン組成物を得ることができるが、
好適にはペレット状にして成形材料とする。A polyethylene composition can be obtained by blending the above-mentioned essential components and, if necessary, optional components, and mixing and kneading with a suitable ordinary mixing and kneading machine.
Preferably, it is made into pellets to obtain a molding material.
【００１５】鋼管にポリエチレン組成物を被覆するに
は、鋼管上に該組成物をチューブ状に押出して被覆する
方法、または該組成物のフラットなシートを押出して鋼
管上に螺旋状に巻き付けて被覆する方法等を採用するこ
とができる。前者の方法では、例えばクロスヘッドダイ
やオフセットダイを使用することができ、また、後者の
方法では、例えばＴダイを使用することができる。被覆
にあたって密着性を良くするため、鋼管自体に物理的処
理や化学的処理を施しても良く、また、粘着剤や接着剤
を介在させても良い。さらには、該組成物自体に接着性
を持たせるため、これを構成するポリエチレンその他の
重合体成分の少なくとも一部に無水マレイン酸の様な官
能基を有する不飽和単量体でグラフト変性処理した重合
体等の接着性重合体を、本発明の効果を著しく損なわな
い範囲で含有させることもできる。To coat a polyethylene composition on a steel pipe, a method of extruding the composition into a tubular form and coating it on the steel pipe, or a method of extruding a flat sheet of the composition and spirally winding the composition onto the steel pipe and coating it It is possible to adopt a method of doing so. In the former method, for example, a cross head die or an offset die can be used, and in the latter method, for example, a T die can be used. In order to improve the adhesion during coating, the steel pipe itself may be subjected to a physical treatment or a chemical treatment, or an adhesive or an adhesive may be interposed. Further, in order to impart adhesiveness to the composition itself, at least a part of polyethylene and other polymer components constituting the composition is graft-modified with an unsaturated monomer having a functional group such as maleic anhydride. An adhesive polymer such as a polymer may be contained in a range that does not significantly impair the effects of the present invention.
【００１６】[0016]
【実施例】以下、具体例をもって本発明をさらに説明す
る。実施例１ ＭＩが０．５７ｇ／１０分、流動比が５４、密度が０．
９２２ｇ／ｃｍ3 、ＥＳＣＲが３０００時間超過、引張
破断点伸度４００％超過の線状低密度ポリエチレン９０
重量％、及び、ＭＩが０．３４ｇ／１０分、流動比が５
９、密度が０．９５６ｇ／ｃｍ3 の高密度ポリエチレン
１０重量％を配合し、これを混練押出機を使用して２３
０℃で混練し、ペレット化した。このペレットを用いて
１９０℃にて熱プレスし、２ｍｍ厚のプレスシートを作
成した。得られたプレスシートを評価した結果を表１に
示す。なお、針入度はＤＩＮ３０６７０に準拠して測定
した。The present invention will be further described below with reference to specific examples. Example 1 MI of 0.57 g / 10 minutes, flow ratio of 54, and density of 0.
922 g / cm 3 , linear low density polyethylene 90 with ESCR exceeding 3000 hours and tensile elongation at break exceeding 400% 90
% By weight, MI 0.34 g / 10 min, flow ratio 5
9. 10% by weight of high-density polyethylene having a density of 0.956 g / cm 3 was blended, and this was mixed with a kneading extruder for 23
The mixture was kneaded at 0 ° C. and pelletized. The pellets were hot-pressed at 190 ° C. to prepare a 2 mm-thick press sheet. The results of evaluating the obtained press sheets are shown in Table 1. The penetration was measured according to DIN30670.
【００１７】実施例２ 実施例１において、配合比を線状低密度ポリエチレン７
０重量％及び高密度ポリエチレン３０重量％としたほか
は実施例１と同様にして評価した結果を表１に示す。 Example 2 In Example 1, the mixing ratio was changed to linear low density polyethylene 7
Table 1 shows the results of evaluation performed in the same manner as in Example 1 except that the content was 0% by weight and the high-density polyethylene was 30% by weight.
【００１８】実施例３ 実施例２において、高密度ポリエチレンとしてＭＩが
０．２１ｇ／１０分、流動比が６１、密度が０．９４４
ｇ／ｃｍ3 の高密度ポリエチレンを用いたほかは実施例
２と同様にして評価した結果を表１に示す。 Example 3 In Example 2, as high-density polyethylene, MI was 0.21 g / 10 min, flow ratio was 61, and density was 0.944.
Table 1 shows the results of evaluation performed in the same manner as in Example 2 except that high-density polyethylene of g / cm 3 was used.
【００１９】実施例４ 実施例２において、高密度ポリエチレンとしてＭＩが
０．０５２ｇ／１０分、流動比が１０７、密度が０．９
５６ｇ／ｃｍ3 の高密度ポリエチレンを用いたほかは実
施例２と同様にして評価した結果を表１に示す。 Example 4 In Example 2, as high density polyethylene, MI was 0.052 g / 10 min, flow ratio was 107, and density was 0.9.
Table 1 shows the results of evaluation performed in the same manner as in Example 2 except that high-density polyethylene of 56 g / cm 3 was used.
【００２０】比較例１ 実施例１において、高密度ポリエチレンを配合しないほ
かは実施例１と同様にして評価した結果を表１に示す。 Comparative Example 1 Table 1 shows the results of evaluation in the same manner as in Example 1 except that high density polyethylene was not blended.
【００２１】比較例２ 実施例１において、配合比を線状低密度ポリエチレン５
０重量％及び高密度ポリエチレン５０重量％としたほか
は実施例１と同様にして評価した結果を表１に示す。 Comparative Example 2 In Example 1, the mixing ratio was changed to linear low density polyethylene 5
Table 1 shows the results of evaluation performed in the same manner as in Example 1 except that the content was 0 wt% and the high-density polyethylene was 50 wt%.
【００２２】比較例３ 実施例２において、高密度ポリエチレンとしてＭＩが１
６．４ｇ／１０分、流動比が２２、密度が０．９５３ｇ
／ｃｍ3 の高密度ポリエチレンを用いたほかは実施例２
と同様にして評価した結果を表１に示す。 Comparative Example 3 In Example 2, the high density polyethylene had MI of 1
6.4g / 10min, flow ratio 22 and density 0.953g
Example 2 with the exception of using high density polyethylene / cm 3
Table 1 shows the results of the evaluation performed in the same manner as described above.
【００２３】比較例４ 実施例３において、線状低密度ポリエチレンとしてＭＩ
が３６ｇ／１０分、流動比が２０、密度が０．９３７ｇ
／ｃｍ3 、ＥＳＣＲが１時間、引張破断点伸度５０％の
線状低密度ポリエチレンを用いたほかは実施例３と同様
にして評価した結果を表１に示す。 Comparative Example 4 In Example 3, MI was used as the linear low density polyethylene.
Is 36 g / 10 minutes, flow ratio is 20, density is 0.937 g
/ Cm 3, ESCR is 1 hour, except for using a tensile elongation at break of 50% linear low density polyethylene are shown in Table 1 the results of evaluation in the same manner as in Example 3.
【００２４】[0024]
【表１】 [Table 1]
【００２５】[0025]
【発明の効果】本発明によれば、低温物性及びＥＳＣＲ
に優れ、かつ高温での針入度の改良された鋼管被覆用ポ
リエチレン組成物が得られるといった顕著な効果が奏さ
れる。According to the present invention, low temperature physical properties and ESCR
And a remarkable effect that a polyethylene composition for coating a steel pipe having an improved penetration at high temperature can be obtained.
フロントページの続き (51)Int.Cl.6 識別記号 庁内整理番号 ＦＩ 技術表示箇所 Ｃ０９Ｄ 123:06） Continuation of front page (51) Int.Cl. 6 Identification code Office reference number FI technical display area C09D 123: 06)
Claims (3)
０分、耐ストレスクラック性（ＥＳＣＲ）１０００時間
以上、かつ、−４５℃での引張破断点伸度２００％以上
の線状低密度ポリエチレン６０〜９０重量％及びメルト
インデックス１ｇ／１０分以下、流動比５０以上、密度
０．９４ｇ／ｃｍ3 以上の高密度ポリエチレン１０〜４
０重量％を含有してなることを特徴とする鋼管被覆用ポ
リエチレン組成物。1. A melt index of 0.1 to 1.5 g / 1.
0 minute, stress crack resistance (ESCR) 1000 hours or more, and 60 to 90% by weight of linear low density polyethylene having a tensile elongation at break of 200% or more at -45 ° C and a melt index of 1 g / 10 minutes or less, flow High density polyethylene 10-4 with a ratio of 50 or more and a density of 0.94 g / cm 3 or more
A polyethylene composition for coating a steel pipe, which comprises 0% by weight.
〜０．９３ｇ／ｃｍ3 のポリエチレンである、請求項１
に記載の組成物。2. The linear low density polyethylene has a density of 0.91.
A polyethylene ~0.93g / cm 3, claim 1
A composition according to claim 1.
上のポリエチレンである、請求項１に記載の組成物。3. The composition according to claim 1, wherein the linear low density polyethylene is a polyethylene having a flow ratio of 45 or more.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP5159196A JPH09241437A (en) | 1996-03-08 | 1996-03-08 | Polyethylene composition for applying steel pipe |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP5159196A JPH09241437A (en) | 1996-03-08 | 1996-03-08 | Polyethylene composition for applying steel pipe |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| JPH09241437A true JPH09241437A (en) | 1997-09-16 |
Family
ID=12891168
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP5159196A Pending JPH09241437A (en) | 1996-03-08 | 1996-03-08 | Polyethylene composition for applying steel pipe |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPH09241437A (en) |
Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO2003085044A1 (en) * | 2002-03-29 | 2003-10-16 | Media Plus, Inc. | High density polyethylene melt blends for improved stress crack resistance in pipe. |
| CN100465219C (en) * | 2006-12-04 | 2009-03-04 | 广州市鹿山化工材料有限公司 | Cross-linked polyethylene composition powder and its prepn |
| JP2014514417A (en) * | 2011-05-06 | 2014-06-19 | ボレアリス アクチエンゲゼルシャフト | Coating composition |
| CN104130472A (en) * | 2014-06-26 | 2014-11-05 | 合肥和安机械制造有限公司 | Filler specialized for tear-resistant and low temperature-resistant high-pressure rubber hose, and preparation method thereof |
-
1996
- 1996-03-08 JP JP5159196A patent/JPH09241437A/en active Pending
Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO2003085044A1 (en) * | 2002-03-29 | 2003-10-16 | Media Plus, Inc. | High density polyethylene melt blends for improved stress crack resistance in pipe. |
| CN100465219C (en) * | 2006-12-04 | 2009-03-04 | 广州市鹿山化工材料有限公司 | Cross-linked polyethylene composition powder and its prepn |
| JP2014514417A (en) * | 2011-05-06 | 2014-06-19 | ボレアリス アクチエンゲゼルシャフト | Coating composition |
| CN104130472A (en) * | 2014-06-26 | 2014-11-05 | 合肥和安机械制造有限公司 | Filler specialized for tear-resistant and low temperature-resistant high-pressure rubber hose, and preparation method thereof |
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