JPH09201904A - Polyethylene coated steel pipe - Google Patents
Polyethylene coated steel pipeInfo
- Publication number
- JPH09201904A JPH09201904A JP1157196A JP1157196A JPH09201904A JP H09201904 A JPH09201904 A JP H09201904A JP 1157196 A JP1157196 A JP 1157196A JP 1157196 A JP1157196 A JP 1157196A JP H09201904 A JPH09201904 A JP H09201904A
- Authority
- JP
- Japan
- Prior art keywords
- steel pipe
- coating
- polyethylene
- polyethylene layer
- coated steel
- 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.)
- Withdrawn
Links
Landscapes
- Laminated Bodies (AREA)
Abstract
Description
【０００１】[0001]
【発明の属する技術分野】本発明は鋼管表面にポリエチ
レン被覆を施した鋼管に関し、さらに詳しくは被覆の剥
離除去が容易でかつ被覆上からのねじ切りが可能なポリ
エチレン被覆鋼管に関する。BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a steel pipe whose surface is coated with polyethylene, and more particularly to a polyethylene-coated steel pipe in which the coating can be easily peeled off and can be threaded from the coating.
【０００２】[0002]
【従来の技術】ガス配管、水道配管、油輸送配管、電線
ケーブル保護管などに鋼管が利用される。これらの配管
は鋼管の腐食防止のために、一般に鋼管の外面にポリエ
チレン被覆が施される。この被覆は長期に渡り優れた防
食性を維持できるので、広く利用されている。2. Description of the Related Art Steel pipes are used for gas pipes, water pipes, oil transportation pipes, electric wire cable protection pipes and the like. In order to prevent corrosion of the steel pipe, these pipes are generally coated with polyethylene on the outer surface of the steel pipe. This coating is widely used because it can maintain excellent corrosion resistance for a long period of time.
【０００３】[0003]
【発明が解決しようとする課題】しかし、従来のポリエ
チレン被覆鋼管は被覆が鋼管と強固に接着しているの
で、溶接継ぎ手による配管施工を行うため端部被覆を剥
離除去する時、鋼管の内部から加熱して被覆の接着力を
低下させる必要があり作業性が悪い。また、鋼管との接
着性が弱い変性ポリエチレン層を選択し予め被覆の接着
力を低くすると、ねじ継ぎ手による配管施工を行うため
被覆上からねじ切りをする時、締め付け治具部分の被覆
が剪断力により剥離し防食性が損なわれる。すなわち、
被覆の剥離除去が容易でかつ被覆上からのねじ切りが可
能なポリエチレン被覆鋼管の実現が難しかった。However, since the coating of the conventional polyethylene-coated steel pipe is firmly adhered to the steel pipe, it is necessary to remove the end coating from the inside of the steel pipe when removing and removing the end coating in order to carry out pipe construction using a welded joint. Workability is poor because it is necessary to heat the coating to reduce the adhesive strength. Also, if a modified polyethylene layer with weak adhesion to the steel pipe is selected and the adhesive strength of the coating is lowered beforehand, when the thread is cut from above the coating to perform piping work with a screw joint, the coating of the tightening jig part will be affected by shearing force. It peels off and impairs the corrosion resistance. That is,
It has been difficult to realize a polyethylene-coated steel pipe that can be easily peeled off the coating and that can be threaded on the coating.
【０００４】[0004]
【発明の目的】本発明は被覆の剥離除去が容易でかつ被
覆上からのねじ切りが可能なポリエチレン被覆鋼管の実
現を目的としたものである。An object of the present invention is to realize a polyethylene-coated steel pipe in which the coating can be easily peeled off and can be threaded on the coating.
【０００５】[0005]
【課題を解決するための手段】本発明者らは、上述の問
題点を解決すべく、被覆の剥離除去が容易でかつ被覆上
からのねじ切りが可能なポリエチレン被覆鋼管について
鋭意検討した。その結果、図１に示す如く、外面を下地
処理した鋼管１の表面に、変性ポリエチレン層２を介し
てポリエチレン層３を被覆した被覆鋼管において、変性
ポリエチレン層被覆時の鋼管温度を１２０〜１６０℃と
することによって、上述の問題点が解決できることを見
出し、本発明に至ったものである。In order to solve the above-mentioned problems, the present inventors have earnestly studied a polyethylene-coated steel pipe in which the coating can be easily peeled off and can be threaded from the coating. As a result, as shown in FIG. 1, in the coated steel pipe in which the polyethylene layer 3 is coated on the surface of the steel pipe 1 having the outer surface subjected to the surface treatment, the temperature of the steel pipe at the time of coating the modified polyethylene layer is 120 to 160 ° C. The inventors have found that the above problems can be solved by the above, and have reached the present invention.
【０００６】以下に、本発明につき詳細に説明する。The present invention will be described in detail below.
【０００７】本発明に使用する鋼管とは、炭素鋼あるい
はステンレス鋼などの合金鋼でできた鋼管である。ま
た、炭素鋼でできた鋼管の内面や外面にステンレス鋼や
チタン、アルミニウム、ニッケル、銅などの金属あるい
はニッケル−クロム−モリブテン合金やニッケル−クロ
ム−モリブテン−タングステン合金のような合金を積層
したクラッド鋼管も使用できる。また、炭素鋼でできた
鋼管の内面や外面に亜鉛、アルミニウム、クロムなどの
金属めっき、亜鉛−アルミニウム、亜鉛−ニッケルや亜
鉛−ニッケル−クロムなどの合金めっきなどのめっきを
施した鋼管も使用できる。The steel pipe used in the present invention is a steel pipe made of alloy steel such as carbon steel or stainless steel. In addition, a clad in which a metal such as stainless steel, titanium, aluminum, nickel, copper or an alloy such as a nickel-chromium-molybdenum alloy or a nickel-chromium-molybdenum-tungsten alloy is laminated on the inner or outer surface of a steel pipe made of carbon steel. Steel pipes can also be used. Further, a steel pipe made of carbon steel, which has metal plating such as zinc, aluminum, or chromium on its inner or outer surface, or alloy plating such as zinc-aluminum, zinc-nickel, or zinc-nickel-chromium, can be used. .
【０００８】[0008]
【発明の実施の形態】本発明に使用する鋼管の外面に
は、最初に下地処理を施す。まず鋼管外面のスケールな
どをサンド粒、ショット粒、グリット粒などの研掃材で
ブラスト処理し除去する。その後表面にクロメート処理
剤をロール、ブラシや刷毛などで塗布し加熱・焼き付け
て下地処理する。クロメート処理剤は、例えば無水クロ
ム酸の水溶液に有機質の還元剤を添加して加熱し水溶液
中の６価クロムの一部を３価クロムに部分還元した還元
水溶液に、シリカ微粒子を添加・分散した混合物、ある
いは無水クロム酸とリン酸の混合水溶液に有機質の還元
剤を添加して加熱し水溶液中の６価クロムの一部を３価
クロムに部分還元した還元水溶液に、シリカ微粒子を添
加・分散した混合物などを用いる。BEST MODE FOR CARRYING OUT THE INVENTION An outer surface of a steel pipe used in the present invention is first subjected to a surface treatment. First, scales and the like on the outer surface of the steel pipe are removed by blasting with abrasives such as sand grains, shot grains and grit grains. After that, a chromate treatment agent is applied to the surface with a roll, a brush, a brush or the like, and heated and baked to perform a base treatment. As the chromate treating agent, for example, silica fine particles are added and dispersed in a reducing aqueous solution obtained by adding an organic reducing agent to an aqueous solution of chromic anhydride and heating it to partially reduce some of the hexavalent chromium in the aqueous solution to trivalent chromium. Add / disperse silica fine particles to a mixture or to a reduced aqueous solution in which an organic reducing agent is added to a mixed aqueous solution of chromic anhydride and phosphoric acid and heated to partially reduce some of the hexavalent chromium in the aqueous solution to trivalent chromium. A mixture of the above is used.
【０００９】次に下地処理した鋼管外面に、変性ポリエ
チレン層を形成する。変性ポリエチレン層の形成に用い
る変性ポリエチレンとしては、エチレン単独重合体、あ
るいはエチレンとプロピレン、１−ブテン、１−ヘキセ
ン、１−オクテンなどのα−オレフィンを共重合したエ
チレン−α−オレフィン共重合体の単独、またはこれら
の混合物を無水マレイン酸で変性した無水マレイン酸変
性ポリエチレンを用いる。Next, a modified polyethylene layer is formed on the outer surface of the steel pipe subjected to the base treatment. Examples of the modified polyethylene used for forming the modified polyethylene layer include ethylene homopolymers or ethylene-α-olefin copolymers obtained by copolymerizing ethylene and α-olefins such as propylene, 1-butene, 1-hexene, and 1-octene. Or a maleic anhydride-modified polyethylene obtained by modifying a mixture thereof with maleic anhydride.
【００１０】本発明の最外層にはポリエチレン層を被覆
する。ポリエチレンとしては、エチレン単独重合体、あ
るいはエチレンとプロピレン、１−ブテン、１−ヘキセ
ン、１−オクテンなどのα−オレフィンを共重合したエ
チレン−α−オレフィン共重合体の単独、またはこれら
の混合物に顔料を混合した混合物を使用する。The outermost layer of the present invention is coated with a polyethylene layer. As polyethylene, ethylene homopolymer, or ethylene-α-olefin copolymer obtained by copolymerizing ethylene and α-olefin such as propylene, 1-butene, 1-hexene, and 1-octene, or a mixture thereof. A mixture of pigments is used.
【００１１】顔料には、例えばカーボンブラック
（黒）、フタロシアニングリーン（緑）の他、イソイン
ドリノンイエロー（黄）、キナクリドンレッド（赤）、
ペリノンレッド（赤）、フタロシアニンブルー（青）な
どの一般市販の有機顔料や、酸化チタン（白）、酸化ク
ロム（緑）、酸化鉄（黄、赤）、チタンイエロー
（黄）、酸化コバルト（青、紫）などの一般市販の無機
顔料の中から適時選択して混合し、所望の色彩に調色す
る。Examples of pigments include carbon black (black), phthalocyanine green (green), isoindolinone yellow (yellow), quinacridone red (red),
General commercially available organic pigments such as perinone red (red) and phthalocyanine blue (blue), titanium oxide (white), chromium oxide (green), iron oxide (yellow, red), titanium yellow (yellow), cobalt oxide (blue, A commercially available inorganic pigment such as purple) is appropriately selected and mixed to prepare a desired color.
【００１２】これらのポリエチレンは、Ｔダイや丸ダイ
によって変性ポリエチレン層を被覆した鋼管外面に押出
被覆して積層するが、変性ポリエチレンとポリエチレン
を二層一体で、二層Ｔダイや二層丸ダイから押出被覆す
る方法も使用できる。この時変性ポリエチレン層被覆時
の鋼管温度が１２０〜１６０℃となるように加熱の強度
を調整する。These polyethylenes are extrusion-coated on the outer surface of the steel pipe coated with the modified polyethylene layer by a T die or a round die, and the modified polyethylene and polyethylene are integrated into two layers to form a two-layer T die or a two-layer round die. It is also possible to use a method of extrusion coating. At this time, the heating strength is adjusted so that the temperature of the steel pipe during coating with the modified polyethylene layer is 120 to 160 ° C.
【００１３】クロメート被膜の全クロム付着量は１５０
〜１０００ｍｇ／ｍ2 、変性ポリエチレン層の厚みは１
００〜５００μｍ、ポリエチレン層の厚みは１〜１０ｍ
ｍであると良好な結果が得られる。The total amount of chromium deposited on the chromate film is 150.
1000 mg / m 2, the thickness of the modified polyethylene layer 1
00-500 μm, the thickness of the polyethylene layer is 1-10 m
Good results are obtained with m.
【００１４】本発明の構成を図１で説明する。The structure of the present invention will be described with reference to FIG.
【００１５】図１は本発明の一例としてポリエチレン被
覆鋼管の一部断面を示す図である。図中１はブラスト処
理で除錆し下地処理した鋼管、２は変性ポリエチレン層
（被覆時の鋼管温度＝１２０〜１６０℃）、３はポリエ
チレン層を各々示す。FIG. 1 is a view showing a partial cross section of a polyethylene-coated steel pipe as an example of the present invention. In the figure, 1 is a steel pipe that has been rust-treated by blasting and has been pretreated, 2 is a modified polyethylene layer (steel pipe temperature during coating = 120 to 160 ° C.), and 3 is a polyethylene layer.
【００１６】[0016]
【発明の作用】本発明のポリエチレン被覆鋼管は被覆の
剥離除去が容易でかつ被覆上からのねじ切りが可能なの
で、溶接継ぎ手やねじ継ぎ手による配管施工の作業性が
良い。The polyethylene-coated steel pipe of the present invention is easy to peel off the coating and can be thread-cut from the coating, so that the workability of pipe construction with a welding joint or a screw joint is good.
【００１７】[0017]
【実施例】以下に、実施例により本発明を詳細に説明す
る。The present invention will be described below in detail with reference to examples.
【００１８】［実施例１］鋼管（外径８９．１ｍｍ×肉
厚４．２ｍｍ×長さ５５００ｍｍ）の外面をグリッド粒
でブラスト処理し除錆した。その後クロメート処理剤
（水溶液中の全クロムに対する３価クロムの重量比が
０．４、シリカの重量比が２．０、リン酸の重量比が
１．０）をブラシでしごき塗布し乾燥した。クロメート
被膜の全クロム付着量は５００ｍｇ／ｍ2 であった。次
に高周波誘導加熱によって鋼管を１４０℃に加熱し、変
性ポリエチレン（エチレン単独重合体を無水マレイン酸
で変性）とポリエチレン（エチレン単独重合体にフタロ
シアニングリーンを混合）を二層一体で二層丸ダイから
押出被覆して本発明のポリエチレン被覆鋼管１を製造し
た。変性ポリエチレン層の厚みは２００μｍ、ポリエチ
レン層の厚みは２ｍｍであった。また同じ方法で変性ポ
リエチレン層被覆時の鋼管温度を１２０℃に変えた本発
明のポリエチレン被覆鋼管２、変性ポリエチレン層被覆
時の鋼管温度を１６０℃に変えた本発明のポリエチレン
被覆鋼管３を各々製造した。比較のために、同じ方法で
変性ポリエチレン層被覆時の鋼管温度を１１５℃とした
ポリエチレン被覆鋼管４、変性ポリエチレン層被覆時の
鋼管温度を１６５℃としたポリエチレン被覆鋼管５を各
々製造した。これらのポリエチレン被覆鋼管の被覆の接
着力をＪＩＳ Ｇ ３４６９に規定の方法で測定した結
果と被覆上からねじ切りをした時の締め付け治具部分の
被覆剥離有無を観察した結果を、表１に示す。表１か
ら、変性ポリエチレン層被覆時の鋼管温度を１２０〜１
６０℃とした本発明のポリエチレン被覆鋼管１〜３はい
ずれも、この範囲の鋼管温度を外れたポリエチレン被覆
鋼管４、ポリエチレン被覆鋼管５に比較して、被覆の接
着力が５ｋｇ／ｃｍ以下で被覆の剥離除去が容易でかつ
被覆上からねじ切りをした時の締め付け治具部分の被覆
剥離が無く防食性が損なわれない。すなわち、本発明の
構成要件である変性ポリエチレン層被覆時の鋼管温度＝
１２０〜１６０℃を外れると被覆の接着力が５ｋｇ／ｃ
ｍを越え被覆の剥離除去が困難となるかあるいは被覆上
からねじ切りをした時の締め付け治具部分の被覆剥離が
有り防食性が損なわれる。[Example 1] The outer surface of a steel pipe (outer diameter 89.1 mm x wall thickness 4.2 mm x length 5500 mm) was blasted with grid grains to remove rust. Then, a chromate treating agent (weight ratio of trivalent chromium to total chromium in the aqueous solution was 0.4, weight ratio of silica was 2.0, and weight ratio of phosphoric acid was 1.0) was applied with a brush and dried. The total amount of chromium deposited on the chromate film was 500 mg / m 2 . Next, the steel pipe is heated to 140 ° C by high frequency induction heating, and modified polyethylene (ethylene homopolymer is modified with maleic anhydride) and polyethylene (ethylene homopolymer mixed with phthalocyanine green) are combined into a two-layer circular die. Was extrusion coated to produce a polyethylene-coated steel pipe 1 of the present invention. The modified polyethylene layer had a thickness of 200 μm, and the polyethylene layer had a thickness of 2 mm. Further, the same method was used to produce the polyethylene-coated steel pipe 2 of the present invention in which the temperature of the modified polyethylene layer was 120 ° C. and the polyethylene-coated steel pipe 3 of the invention in which the temperature of the modified polyethylene layer was 160 ° C. did. For comparison, a polyethylene-coated steel pipe 4 having a modified polyethylene layer coating temperature of 115 ° C. and a polyethylene-coated steel pipe 5 having a modified polyethylene layer coating temperature of 165 ° C. were manufactured by the same method. Table 1 shows the results of measuring the adhesive strength of the coating of these polyethylene-coated steel pipes by the method specified in JIS G 3469 and observing the presence or absence of coating peeling of the tightening jig portion when the thread is cut from above the coating. From Table 1, the steel pipe temperature at the time of coating the modified polyethylene layer is 120 to 1
All of the polyethylene-coated steel pipes 1 to 3 of the present invention set to 60 ° C. have a coating adhesive force of 5 kg / cm or less as compared with the polyethylene-coated steel pipe 4 and the polyethylene-coated steel pipe 5 which are out of the steel pipe temperature within this range. It is easy to remove and remove, and the coating of the tightening jig part does not peel when the thread is cut from the coating, and corrosion resistance is not impaired. That is, the temperature of the steel pipe when coated with the modified polyethylene layer, which is a constituent of the present invention,
When the temperature is out of 120 to 160 ° C, the adhesive strength of the coating is 5 kg / c
If the thickness exceeds m, it becomes difficult to remove the coating, or the coating of the tightening jig part is peeled off when the coating is screwed, and the corrosion resistance is impaired.
【００１９】[0019]
【表１】 [Table 1]
【００２０】[0020]
【発明の効果】本発明のポリエチレン被覆鋼管は、実施
例からも明らかなように、被覆の剥離除去が容易でかつ
被覆上からのねじ切りが可能なので、溶接継ぎ手やねじ
継ぎ手による配管施工の作業性が良い。As is clear from the examples, the polyethylene-coated steel pipe of the present invention is easy to peel off the coating and can be threaded on the coating. Therefore, the workability of pipe installation by a welding joint or a screw joint is improved. Is good.
【図１】本発明の一例としてポリエチレン被覆鋼管の一
部断面を示す図。FIG. 1 is a diagram showing a partial cross section of a polyethylene-coated steel pipe as an example of the present invention.
１…ブラスト処理で除錆し下地処理した鋼管 ２…変性ポリエチレン層（被覆時の鋼管温度＝１２０〜
１６０℃） ３…ポリエチレン層1 ... Steel pipe that has been rust-removed by blasting and pre-treated 2 ... Modified polyethylene layer (steel pipe temperature during coating = 120-
160 ℃) 3 ... Polyethylene layer
───────────────────────────────────────────────────── フロントページの続き (72)発明者 末内康博 君津市君津１番地 新日本製鐵株式会社君 津製鐵所内 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Yasuhiro Sueuchi 1 Kimitsu, Kimitsu City Nippon Steel Corporation Kimitsu Steel Works
Claims (1)
トによる下地処理を施した後、変性ポリエチレン層とポ
リエチレン層を順次積層する被覆鋼管において、変性ポ
リエチレン層被覆時の鋼管温度を１２０〜１６０℃とし
たことを特徴とするポリエチレン被覆鋼管。1. A coated steel pipe in which a modified polyethylene layer and a polyethylene layer are sequentially laminated after blasting the surface of the steel pipe and subjecting it to a base treatment with chromate, and the temperature of the modified polyethylene layer is 120 to 160 ° C. A polyethylene-coated steel pipe characterized in that
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP1157196A JPH09201904A (en) | 1996-01-26 | 1996-01-26 | Polyethylene coated steel pipe |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP1157196A JPH09201904A (en) | 1996-01-26 | 1996-01-26 | Polyethylene coated steel pipe |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| JPH09201904A true JPH09201904A (en) | 1997-08-05 |
Family
ID=11781619
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP1157196A Withdrawn JPH09201904A (en) | 1996-01-26 | 1996-01-26 | Polyethylene coated steel pipe |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPH09201904A (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2016068968A (en) * | 2014-09-29 | 2016-05-09 | 昭和電工パッケージング株式会社 | Method of producing laminate housing material |
-
1996
- 1996-01-26 JP JP1157196A patent/JPH09201904A/en not_active Withdrawn
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2016068968A (en) * | 2014-09-29 | 2016-05-09 | 昭和電工パッケージング株式会社 | Method of producing laminate housing material |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| A300 | Withdrawal of application because of no request for examination |
Free format text: JAPANESE INTERMEDIATE CODE: A300 Effective date: 20030401 |