JPS6220911B2 - - Google Patents
Info
- Publication number
- JPS6220911B2 JPS6220911B2 JP8471183A JP8471183A JPS6220911B2 JP S6220911 B2 JPS6220911 B2 JP S6220911B2 JP 8471183 A JP8471183 A JP 8471183A JP 8471183 A JP8471183 A JP 8471183A JP S6220911 B2 JPS6220911 B2 JP S6220911B2
- Authority
- JP
- Japan
- Prior art keywords
- polyethylene
- resin
- molecular weight
- layer
- protective layer
- 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
Links
- -1 polyethylene Polymers 0.000 claims description 24
- 239000004698 Polyethylene Substances 0.000 claims description 15
- 229910052751 metal Inorganic materials 0.000 claims description 15
- 239000002184 metal Substances 0.000 claims description 15
- 229920000573 polyethylene Polymers 0.000 claims description 15
- 229920005989 resin Polymers 0.000 claims description 15
- 239000011347 resin Substances 0.000 claims description 15
- 239000010410 layer Substances 0.000 claims description 13
- 239000011241 protective layer Substances 0.000 claims description 13
- 239000004743 Polypropylene Substances 0.000 claims description 9
- 229920001155 polypropylene Polymers 0.000 claims description 9
- 239000000155 melt Substances 0.000 claims description 2
- 239000000853 adhesive Substances 0.000 description 7
- 230000001070 adhesive effect Effects 0.000 description 7
- 229910000831 Steel Inorganic materials 0.000 description 6
- 239000010959 steel Substances 0.000 description 6
- 238000000034 method Methods 0.000 description 5
- 238000005260 corrosion Methods 0.000 description 4
- 239000003795 chemical substances by application Substances 0.000 description 3
- 239000003822 epoxy resin Substances 0.000 description 3
- VLKZOEOYAKHREP-UHFFFAOYSA-N n-Hexane Chemical compound CCCCCC VLKZOEOYAKHREP-UHFFFAOYSA-N 0.000 description 3
- 229920000647 polyepoxide Polymers 0.000 description 3
- VTYYLEPIZMXCLO-UHFFFAOYSA-L Calcium carbonate Chemical compound [Ca+2].[O-]C([O-])=O VTYYLEPIZMXCLO-UHFFFAOYSA-L 0.000 description 2
- IMNFDUFMRHMDMM-UHFFFAOYSA-N N-Heptane Chemical compound CCCCCCC IMNFDUFMRHMDMM-UHFFFAOYSA-N 0.000 description 2
- IISBACLAFKSPIT-UHFFFAOYSA-N bisphenol A Chemical compound C=1C=C(O)C=CC=1C(C)(C)C1=CC=C(O)C=C1 IISBACLAFKSPIT-UHFFFAOYSA-N 0.000 description 2
- 239000011248 coating agent Substances 0.000 description 2
- 238000000576 coating method Methods 0.000 description 2
- 238000005227 gel permeation chromatography Methods 0.000 description 2
- 229920001903 high density polyethylene Polymers 0.000 description 2
- 239000004700 high-density polyethylene Substances 0.000 description 2
- 238000004519 manufacturing process Methods 0.000 description 2
- 239000003960 organic solvent Substances 0.000 description 2
- 229920001187 thermosetting polymer Polymers 0.000 description 2
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 2
- 238000003466 welding Methods 0.000 description 2
- RYGMFSIKBFXOCR-UHFFFAOYSA-N Copper Chemical compound [Cu] RYGMFSIKBFXOCR-UHFFFAOYSA-N 0.000 description 1
- VGGSQFUCUMXWEO-UHFFFAOYSA-N Ethene Chemical compound C=C VGGSQFUCUMXWEO-UHFFFAOYSA-N 0.000 description 1
- 239000005977 Ethylene Substances 0.000 description 1
- 239000006096 absorbing agent Substances 0.000 description 1
- 239000000654 additive Substances 0.000 description 1
- 150000001338 aliphatic hydrocarbons Chemical class 0.000 description 1
- 230000003141 anti-fusion Effects 0.000 description 1
- 239000003963 antioxidant agent Substances 0.000 description 1
- 229920001400 block copolymer Polymers 0.000 description 1
- 229910000019 calcium carbonate Inorganic materials 0.000 description 1
- 239000003054 catalyst Substances 0.000 description 1
- 238000006243 chemical reaction Methods 0.000 description 1
- 230000000052 comparative effect Effects 0.000 description 1
- 238000007796 conventional method Methods 0.000 description 1
- 229910052802 copper Inorganic materials 0.000 description 1
- 239000010949 copper Substances 0.000 description 1
- 230000007797 corrosion Effects 0.000 description 1
- 230000032798 delamination Effects 0.000 description 1
- 229920001038 ethylene copolymer Polymers 0.000 description 1
- 239000003063 flame retardant Substances 0.000 description 1
- 230000004927 fusion Effects 0.000 description 1
- 238000010438 heat treatment Methods 0.000 description 1
- 229920000092 linear low density polyethylene Polymers 0.000 description 1
- 239000004707 linear low-density polyethylene Substances 0.000 description 1
- 229920001684 low density polyethylene Polymers 0.000 description 1
- 239000004702 low-density polyethylene Substances 0.000 description 1
- 239000000314 lubricant Substances 0.000 description 1
- 239000000463 material Substances 0.000 description 1
- 239000000203 mixture Substances 0.000 description 1
- 229920001083 polybutene Polymers 0.000 description 1
- 229920013716 polyethylene resin Polymers 0.000 description 1
- 238000006116 polymerization reaction Methods 0.000 description 1
- 229920000098 polyolefin Polymers 0.000 description 1
- 239000000843 powder Substances 0.000 description 1
- QQONPFPTGQHPMA-UHFFFAOYSA-N propylene Natural products CC=C QQONPFPTGQHPMA-UHFFFAOYSA-N 0.000 description 1
- 125000004805 propylene group Chemical group [H]C([H])([H])C([H])([*:1])C([H])([H])[*:2] 0.000 description 1
- 150000003839 salts Chemical class 0.000 description 1
- 238000005507 spraying Methods 0.000 description 1
- 239000000454 talc Substances 0.000 description 1
- 229910052623 talc Inorganic materials 0.000 description 1
- 229920001169 thermoplastic Polymers 0.000 description 1
- 239000004416 thermosoftening plastic Substances 0.000 description 1
- 238000005406 washing Methods 0.000 description 1
- 239000004711 α-olefin Substances 0.000 description 1
Description
本発明は樹脂被覆金属管に関し、詳しくは防食
層と保護層との剥離が容易で、かつ生産性に優れ
た樹脂被覆金属管に関する。
水道用、ガス用、ケーブル保護用などの金属管
として用いられるポリエチレン被覆鋼管は、一般
に鋼管表面に防食用のポリエチレン樹脂層と輸送
取扱などのための保護層が形成されている。かか
る樹脂被覆鋼管を溶接する場合はその保護層を剥
離する必要がある。そこで２層間の融着を防止す
るため、低分子量ポリオレフイン、ポリブテンな
どの融着防止剤を塗布する方法（実公昭50−2083
号）、炭酸カルシウム、滑石などの無機質粉末を
融着防止剤として散布する方法（特開昭50−
139422号）が採用されている。しかし、これらの
従来法では製造工程が複雑になり、生産性が低下
するという欠点があつた。
また、保護層としてポリエチレンとポリプロピ
レンからなる組成物を用いる方法（特開昭58−
42449号）も知られているが、耐傷付性が十分で
なかつた。
本発明者らは、上記欠点を除去した樹脂被覆鋼
管を開発するため、保護層をポリプロピレンと
し、防食層としての種々のポリエチレンとの剥離
強度を測定した。その結果、所定のメルトインデ
ツクス（MI）と低分子量成分含有量を有するポ
リエチレンを用いると、保護層としてのポリプロ
ピレンとの剥離が容易であり、かつ成形性、生産
性が極めて向上することを見出し、本発明を完成
した。
すなわち本発明は、ポリエチレン防食層とポリ
プロピレン保護層からなる樹脂で被覆した金属管
において、防食層としてのポリエチレンが、メル
トインデツクスが0.5ｇ／10分以下であり、重量
平均分子量1000〜3000の低分子量成分の含有量が
0.05〜0.5重量％のものであることを特徴とする
樹脂被覆金属管を提供するものである。
本発明において防食層として用いるポリエチレ
ンは、MIが0.5ｇ／10分以下、好ましくは0.30〜
0.15ｇ／10分の範囲にある。MIが0.5ｇ／10分を
超えると、管被覆する場合の成形性が悪化する。
また、ゲル浸透クロマトグラフイー（GPC）に
より測定した重量平均分子量が1000〜3000の低分
子量成分の含有量が0.05〜0.5重量％、好ましく
は0.1〜0.3重量％のものでなければならない。低
分子量成分の含有量が0.05重量％未満であると、
成形性が悪化し、0.5重量％を超えると、層間剥
離強度が大きくなり剥離作業が困難となる。
かかるポリエチレンの製造は従来公知の方法で
行なうことができる。例えば、高密度ポリエチレ
ン、中低密度ポリエチレン、直鎖状低密度ポリエ
チレン、他のα−オレフインを20重量％以下含有
するエチレン共重合体の１種又は２種以上を有機
溶剤と加熱下で２〜10時間接触させて洗浄し、低
分子量成分を除去することにより得ることができ
る。これらの中では、特に高密度ポリエチレンか
ら低分子量成分を除去したものが好ましい。用い
ることのできる有機溶剤としては特に制限はない
が、通常ヘキサン、ヘプタンなどの脂肪族炭化水
素を使用する。
また、適当な触媒、重合方法を採用することに
より低分子量成分含有量の少ないポリエチレンを
直接製造することもできる。
本発明において保護層として用いるポリプロピ
レンは特に制限はないが、特にエチレン含量10〜
40重量％のプロピレンブロツクコポリマーが好ま
しい。
樹脂被覆金属管の製造は、鋼管、銅管、鉛管な
どの金属管上に樹脂材料をチユーブ状に押出して
被覆する方法、樹脂シートをらせん状に巻き付け
て被覆する方法などによつて行なうことができ
る。製造に際しては必要に応じてプライマー処
理、加熱処理などを行なう。また、ポリエチレ
ン、ポリプロピレン中に酸化防止剤、紫外線吸収
剤、滑剤、難燃剤などの各種添加剤を添加するこ
ともできる。また、金属管とポリエチレン防食層
との間の接着強度、耐温塩水性を向上させるため
に、金属管表面に接着剤を塗布することもでき
る。その場合、接着剤としては、熱硬化性エポキ
シ樹脂接着剤、熱可塑性エポキシ樹脂接着剤など
公知のものを用いることができる。
本発明の樹脂被覆金属管は、防食層として所定
のポリエチレンを用いているため、保護層との剥
離が容易であり、溶接時などの作業性に優れてい
る。また、剥離強度の温度依存性が小さいため、
保護層重ね合せ時の温度管理が不要であり、高温
での重ね合せもできる。さらに、金属管の被覆成
形性に優れており、融着防止剤が不要であるた
め、生産性も高い。また、保護層としてポリプロ
ピレンを用いているため耐傷付性、耐久性などが
優れている。従つて、本発明の樹脂被覆金属管は
実用上極めて有用である。
次に、本発明を実施例により説明する。
実施例１〜７および比較例１〜６
サンドブラスト鋼板（厚さ２mm、SPCC−SD）
上に熱硬化性ビスフエノールＡ型エポキシ樹脂接
着剤を塗布し、160℃で10分間硬化反応せしめた
後、ポリエチレンシート（厚さ１mm）を重ねて防
食層とした。次に、保護層としてポリプロピレン
シート（厚さ１mm、樹脂温度190℃）を重ね合せ
て40Kg／cm2で５分間加熱圧着した。結果を第１表
に示す。
The present invention relates to a resin-coated metal tube, and more particularly to a resin-coated metal tube whose anti-corrosion layer and protective layer can be easily peeled off and which has excellent productivity. Polyethylene-coated steel pipes used as metal pipes for water, gas, cable protection, etc. generally have a polyethylene resin layer for corrosion protection and a protective layer for transportation and handling formed on the surface of the steel pipe. When welding such resin-coated steel pipes, it is necessary to peel off the protective layer. Therefore, in order to prevent fusion between the two layers, there is a method of applying an anti-fusion agent such as low molecular weight polyolefin or polybutene (Utility Model Publication No. 50-2083).
No.), a method of spraying inorganic powder such as calcium carbonate or talc as an anti-fusing agent (Japanese Patent Application Laid-Open No. 1973-
No. 139422) has been adopted. However, these conventional methods have the drawback of complicating the manufacturing process and reducing productivity. In addition, a method using a composition consisting of polyethylene and polypropylene as a protective layer (Japanese Patent Application Laid-Open No. 1986-
No. 42449) is also known, but it did not have sufficient scratch resistance. In order to develop a resin-coated steel pipe that eliminates the above drawbacks, the present inventors used polypropylene as a protective layer and measured the peel strength with various polyethylenes as anti-corrosion layers. As a result, we found that when polyethylene with a specified melt index (MI) and low molecular weight component content is used, it is easy to peel off from polypropylene as a protective layer, and moldability and productivity are greatly improved. , completed the invention. That is, the present invention provides a metal tube coated with a resin consisting of a polyethylene anticorrosion layer and a polypropylene protective layer, in which the polyethylene as the anticorrosion layer has a melt index of 0.5 g/10 minutes or less and a low weight average molecular weight of 1000 to 3000. The content of molecular weight components is
The object of the present invention is to provide a resin-coated metal tube characterized in that the resin-coated metal tube contains 0.05 to 0.5% by weight. The polyethylene used as the anticorrosive layer in the present invention has an MI of 0.5 g/10 minutes or less, preferably 0.30 to
It is in the range of 0.15g/10 minutes. When MI exceeds 0.5 g/10 minutes, moldability when coating a tube deteriorates.
Furthermore, the content of low molecular weight components having a weight average molecular weight of 1000 to 3000 as measured by gel permeation chromatography (GPC) must be 0.05 to 0.5% by weight, preferably 0.1 to 0.3% by weight. When the content of low molecular weight components is less than 0.05% by weight,
The moldability deteriorates, and if it exceeds 0.5% by weight, the delamination strength increases and peeling becomes difficult. Such polyethylene can be produced by conventionally known methods. For example, one or more ethylene copolymers containing 20% by weight or less of high-density polyethylene, medium-low-density polyethylene, linear low-density polyethylene, and other α-olefins are mixed with an organic solvent and heated for 2 to 30 minutes. It can be obtained by contacting for 10 hours and washing to remove low molecular weight components. Among these, those obtained by removing low molecular weight components from high density polyethylene are particularly preferred. There are no particular restrictions on the organic solvent that can be used, but aliphatic hydrocarbons such as hexane and heptane are usually used. Furthermore, by employing appropriate catalysts and polymerization methods, it is also possible to directly produce polyethylene with a low content of low molecular weight components. The polypropylene used as the protective layer in the present invention is not particularly limited, but especially has an ethylene content of 10 to
40% by weight propylene block copolymer is preferred. Resin-coated metal pipes can be manufactured by extruding a resin material onto metal pipes such as steel pipes, copper pipes, lead pipes, etc. in the shape of a tube, or by wrapping a resin sheet in a spiral shape. can. During manufacturing, primer treatment, heat treatment, etc. are performed as necessary. Furthermore, various additives such as antioxidants, ultraviolet absorbers, lubricants, and flame retardants can be added to polyethylene and polypropylene. Furthermore, an adhesive can be applied to the surface of the metal tube in order to improve the adhesive strength and resistance to warm salt water between the metal tube and the polyethylene anticorrosive layer. In that case, known adhesives such as thermosetting epoxy resin adhesives and thermoplastic epoxy resin adhesives can be used as the adhesive. Since the resin-coated metal pipe of the present invention uses a specified polyethylene as the anti-corrosion layer, it is easy to peel off the protective layer and has excellent workability during welding. In addition, because the temperature dependence of peel strength is small,
Temperature control is not required when overlapping protective layers, and overlapping can be performed at high temperatures. Furthermore, it has excellent coating moldability for metal tubes and does not require an anti-fusing agent, resulting in high productivity. Additionally, since polypropylene is used as the protective layer, it has excellent scratch resistance and durability. Therefore, the resin-coated metal tube of the present invention is extremely useful in practice. Next, the present invention will be explained by examples. Examples 1 to 7 and Comparative Examples 1 to 6 Sandblasted steel plate (thickness 2 mm, SPCC-SD)
A thermosetting bisphenol A type epoxy resin adhesive was applied on top, and after a curing reaction was performed at 160°C for 10 minutes, a polyethylene sheet (1 mm thick) was layered to form an anticorrosive layer. Next, a polypropylene sheet (thickness: 1 mm, resin temperature: 190° C.) was superimposed as a protective layer and heat-pressed at 40 kg/cm 2 for 5 minutes. The results are shown in Table 1.
【表】【table】
Claims (1)
からなる樹脂層で被覆した金属管において、防食
層としてのポリエチレンが、メルトインデツクス
が0.5ｇ／10分以下であり、重量平均分子量1000
〜3000の低分子量成分の含有量が0.05〜0.5重量
％のものであることを特徴とする樹脂被覆金属
管。1 In a metal pipe coated with a resin layer consisting of a polyethylene anticorrosion layer and a polypropylene protective layer, the polyethylene as the anticorrosion layer has a melt index of 0.5 g/10 minutes or less and a weight average molecular weight of 1000.
A resin-coated metal tube characterized in that the content of low molecular weight components of ~3000 is 0.05 to 0.5% by weight.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP8471183A JPS59209855A (en) | 1983-05-13 | 1983-05-13 | Metallic pipe coated with resin |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP8471183A JPS59209855A (en) | 1983-05-13 | 1983-05-13 | Metallic pipe coated with resin |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPS59209855A JPS59209855A (en) | 1984-11-28 |
| JPS6220911B2 true JPS6220911B2 (en) | 1987-05-09 |
Family
ID=13838243
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP8471183A Granted JPS59209855A (en) | 1983-05-13 | 1983-05-13 | Metallic pipe coated with resin |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPS59209855A (en) |
Families Citing this family (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP5187435B2 (en) * | 2011-02-07 | 2013-04-24 | Ｊｆｅスチール株式会社 | Multi-coated steel pipe |
| JP5187455B1 (en) * | 2012-04-23 | 2013-04-24 | Ｊｆｅスチール株式会社 | Manufacturing method of multi-coated steel pipe |
-
1983
- 1983-05-13 JP JP8471183A patent/JPS59209855A/en active Granted
Also Published As
| Publication number | Publication date |
|---|---|
| JPS59209855A (en) | 1984-11-28 |
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