JP6962216B2 - Anti-rust treatment liquid for welded steel pipes, chemical conversion treatment methods for welded steel pipes, molded products of welded steel pipes and welded steel pipes - Google Patents

Anti-rust treatment liquid for welded steel pipes, chemical conversion treatment methods for welded steel pipes, molded products of welded steel pipes and welded steel pipes Download PDF

Info

Publication number
JP6962216B2
JP6962216B2 JP2018009508A JP2018009508A JP6962216B2 JP 6962216 B2 JP6962216 B2 JP 6962216B2 JP 2018009508 A JP2018009508 A JP 2018009508A JP 2018009508 A JP2018009508 A JP 2018009508A JP 6962216 B2 JP6962216 B2 JP 6962216B2
Authority
JP
Japan
Prior art keywords
welded steel
chemical conversion
treatment liquid
steel pipes
rust preventive
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.)
Active
Application number
JP2018009508A
Other languages
Japanese (ja)
Other versions
JP2019127618A (en
Inventor
雅典 松野
晋 上野
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Nippon Steel Corp
Original Assignee
Nippon Steel Corp
Priority date (The priority date 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 date listed.)
Filing date
Publication date
Application filed by Nippon Steel Corp filed Critical Nippon Steel Corp
Priority to JP2018009508A priority Critical patent/JP6962216B2/en
Priority to CN201980009609.6A priority patent/CN111630206B/en
Priority to PCT/JP2019/001821 priority patent/WO2019146584A1/en
Priority to KR1020207021389A priority patent/KR20200110750A/en
Priority to TW108102764A priority patent/TWI791746B/en
Publication of JP2019127618A publication Critical patent/JP2019127618A/en
Application granted granted Critical
Publication of JP6962216B2 publication Critical patent/JP6962216B2/en
Active legal-status Critical Current
Anticipated expiration legal-status Critical

Links

Images

Classifications

    • C—CHEMISTRY; METALLURGY
    • C23—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; CHEMICAL SURFACE TREATMENT; DIFFUSION TREATMENT OF METALLIC MATERIAL; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL
    • C23C—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; SURFACE TREATMENT OF METALLIC MATERIAL BY DIFFUSION INTO THE SURFACE, BY CHEMICAL CONVERSION OR SUBSTITUTION; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL
    • C23C22/00—Chemical surface treatment of metallic material by reaction of the surface with a reactive liquid, leaving reaction products of surface material in the coating, e.g. conversion coatings, passivation of metals
    • C23C22/05—Chemical surface treatment of metallic material by reaction of the surface with a reactive liquid, leaving reaction products of surface material in the coating, e.g. conversion coatings, passivation of metals using aqueous solutions
    • C23C22/68—Chemical surface treatment of metallic material by reaction of the surface with a reactive liquid, leaving reaction products of surface material in the coating, e.g. conversion coatings, passivation of metals using aqueous solutions using aqueous solutions with pH between 6 and 8
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B05—SPRAYING OR ATOMISING IN GENERAL; APPLYING FLUENT MATERIALS TO SURFACES, IN GENERAL
    • B05D—PROCESSES FOR APPLYING FLUENT MATERIALS TO SURFACES, IN GENERAL
    • B05D3/00—Pretreatment of surfaces to which liquids or other fluent materials are to be applied; After-treatment of applied coatings, e.g. intermediate treating of an applied coating preparatory to subsequent applications of liquids or other fluent materials
    • B05D3/10—Pretreatment of surfaces to which liquids or other fluent materials are to be applied; After-treatment of applied coatings, e.g. intermediate treating of an applied coating preparatory to subsequent applications of liquids or other fluent materials by other chemical means
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B05—SPRAYING OR ATOMISING IN GENERAL; APPLYING FLUENT MATERIALS TO SURFACES, IN GENERAL
    • B05D—PROCESSES FOR APPLYING FLUENT MATERIALS TO SURFACES, IN GENERAL
    • B05D7/00—Processes, other than flocking, specially adapted for applying liquids or other fluent materials to particular surfaces or for applying particular liquids or other fluent materials
    • B05D7/14—Processes, other than flocking, specially adapted for applying liquids or other fluent materials to particular surfaces or for applying particular liquids or other fluent materials to metal, e.g. car bodies
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B05—SPRAYING OR ATOMISING IN GENERAL; APPLYING FLUENT MATERIALS TO SURFACES, IN GENERAL
    • B05D—PROCESSES FOR APPLYING FLUENT MATERIALS TO SURFACES, IN GENERAL
    • B05D7/00—Processes, other than flocking, specially adapted for applying liquids or other fluent materials to particular surfaces or for applying particular liquids or other fluent materials
    • B05D7/14—Processes, other than flocking, specially adapted for applying liquids or other fluent materials to particular surfaces or for applying particular liquids or other fluent materials to metal, e.g. car bodies
    • B05D7/16—Processes, other than flocking, specially adapted for applying liquids or other fluent materials to particular surfaces or for applying particular liquids or other fluent materials to metal, e.g. car bodies using synthetic lacquers or varnishes
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B05—SPRAYING OR ATOMISING IN GENERAL; APPLYING FLUENT MATERIALS TO SURFACES, IN GENERAL
    • B05D—PROCESSES FOR APPLYING FLUENT MATERIALS TO SURFACES, IN GENERAL
    • B05D7/00—Processes, other than flocking, specially adapted for applying liquids or other fluent materials to particular surfaces or for applying particular liquids or other fluent materials
    • B05D7/24—Processes, other than flocking, specially adapted for applying liquids or other fluent materials to particular surfaces or for applying particular liquids or other fluent materials for applying particular liquids or other fluent materials
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B32—LAYERED PRODUCTS
    • B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
    • B32B1/00—Layered products having a non-planar shape
    • B32B1/08—Tubular products
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B32—LAYERED PRODUCTS
    • B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
    • B32B15/00—Layered products comprising a layer of metal
    • B32B15/04—Layered products comprising a layer of metal comprising metal as the main or only constituent of a layer, which is next to another layer of the same or of a different material
    • B32B15/08—Layered products comprising a layer of metal comprising metal as the main or only constituent of a layer, which is next to another layer of the same or of a different material of synthetic resin
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B32—LAYERED PRODUCTS
    • B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
    • B32B15/00—Layered products comprising a layer of metal
    • B32B15/04—Layered products comprising a layer of metal comprising metal as the main or only constituent of a layer, which is next to another layer of the same or of a different material
    • B32B15/08—Layered products comprising a layer of metal comprising metal as the main or only constituent of a layer, which is next to another layer of the same or of a different material of synthetic resin
    • B32B15/082—Layered products comprising a layer of metal comprising metal as the main or only constituent of a layer, which is next to another layer of the same or of a different material of synthetic resin comprising vinyl resins; comprising acrylic resins
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B32—LAYERED PRODUCTS
    • B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
    • B32B15/00—Layered products comprising a layer of metal
    • B32B15/04—Layered products comprising a layer of metal comprising metal as the main or only constituent of a layer, which is next to another layer of the same or of a different material
    • B32B15/08—Layered products comprising a layer of metal comprising metal as the main or only constituent of a layer, which is next to another layer of the same or of a different material of synthetic resin
    • B32B15/09—Layered products comprising a layer of metal comprising metal as the main or only constituent of a layer, which is next to another layer of the same or of a different material of synthetic resin comprising polyesters
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B32—LAYERED PRODUCTS
    • B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
    • B32B15/00—Layered products comprising a layer of metal
    • B32B15/18—Layered products comprising a layer of metal comprising iron or steel
    • C—CHEMISTRY; METALLURGY
    • C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
    • C09D—COATING COMPOSITIONS, e.g. PAINTS, VARNISHES OR LACQUERS; FILLING PASTES; CHEMICAL PAINT OR INK REMOVERS; INKS; CORRECTING FLUIDS; WOODSTAINS; PASTES OR SOLIDS FOR COLOURING OR PRINTING; USE OF MATERIALS THEREFOR
    • C09D5/00—Coating compositions, e.g. paints, varnishes or lacquers, characterised by their physical nature or the effects produced; Filling pastes
    • C09D5/08—Anti-corrosive paints
    • C—CHEMISTRY; METALLURGY
    • C23—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; CHEMICAL SURFACE TREATMENT; DIFFUSION TREATMENT OF METALLIC MATERIAL; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL
    • C23C—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; SURFACE TREATMENT OF METALLIC MATERIAL BY DIFFUSION INTO THE SURFACE, BY CHEMICAL CONVERSION OR SUBSTITUTION; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL
    • C23C22/00—Chemical surface treatment of metallic material by reaction of the surface with a reactive liquid, leaving reaction products of surface material in the coating, e.g. conversion coatings, passivation of metals
    • C23C22/05—Chemical surface treatment of metallic material by reaction of the surface with a reactive liquid, leaving reaction products of surface material in the coating, e.g. conversion coatings, passivation of metals using aqueous solutions
    • C23C22/60—Chemical surface treatment of metallic material by reaction of the surface with a reactive liquid, leaving reaction products of surface material in the coating, e.g. conversion coatings, passivation of metals using aqueous solutions using alkaline aqueous solutions with pH greater than 8
    • C23C22/62—Treatment of iron or alloys based thereon
    • C—CHEMISTRY; METALLURGY
    • C23—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; CHEMICAL SURFACE TREATMENT; DIFFUSION TREATMENT OF METALLIC MATERIAL; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL
    • C23C—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; SURFACE TREATMENT OF METALLIC MATERIAL BY DIFFUSION INTO THE SURFACE, BY CHEMICAL CONVERSION OR SUBSTITUTION; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL
    • C23C28/00—Coating for obtaining at least two superposed coatings either by methods not provided for in a single one of groups C23C2/00 - C23C26/00 or by combinations of methods provided for in subclasses C23C and C25C or C25D
    • C—CHEMISTRY; METALLURGY
    • C23—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; CHEMICAL SURFACE TREATMENT; DIFFUSION TREATMENT OF METALLIC MATERIAL; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL
    • C23C—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; SURFACE TREATMENT OF METALLIC MATERIAL BY DIFFUSION INTO THE SURFACE, BY CHEMICAL CONVERSION OR SUBSTITUTION; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL
    • C23C4/00—Coating by spraying the coating material in the molten state, e.g. by flame, plasma or electric discharge
    • C23C4/18—After-treatment
    • C—CHEMISTRY; METALLURGY
    • C23—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; CHEMICAL SURFACE TREATMENT; DIFFUSION TREATMENT OF METALLIC MATERIAL; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL
    • C23F—NON-MECHANICAL REMOVAL OF METALLIC MATERIAL FROM SURFACE; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL; MULTI-STEP PROCESSES FOR SURFACE TREATMENT OF METALLIC MATERIAL INVOLVING AT LEAST ONE PROCESS PROVIDED FOR IN CLASS C23 AND AT LEAST ONE PROCESS COVERED BY SUBCLASS C21D OR C22F OR CLASS C25
    • C23F1/00—Etching metallic material by chemical means
    • C23F1/10—Etching compositions
    • C23F1/14—Aqueous compositions
    • C23F1/16—Acidic compositions
    • C—CHEMISTRY; METALLURGY
    • C23—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; CHEMICAL SURFACE TREATMENT; DIFFUSION TREATMENT OF METALLIC MATERIAL; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL
    • C23F—NON-MECHANICAL REMOVAL OF METALLIC MATERIAL FROM SURFACE; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL; MULTI-STEP PROCESSES FOR SURFACE TREATMENT OF METALLIC MATERIAL INVOLVING AT LEAST ONE PROCESS PROVIDED FOR IN CLASS C23 AND AT LEAST ONE PROCESS COVERED BY SUBCLASS C21D OR C22F OR CLASS C25
    • C23F1/00—Etching metallic material by chemical means
    • C23F1/10—Etching compositions
    • C23F1/14—Aqueous compositions
    • C23F1/32—Alkaline compositions
    • C—CHEMISTRY; METALLURGY
    • C23—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; CHEMICAL SURFACE TREATMENT; DIFFUSION TREATMENT OF METALLIC MATERIAL; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL
    • C23F—NON-MECHANICAL REMOVAL OF METALLIC MATERIAL FROM SURFACE; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL; MULTI-STEP PROCESSES FOR SURFACE TREATMENT OF METALLIC MATERIAL INVOLVING AT LEAST ONE PROCESS PROVIDED FOR IN CLASS C23 AND AT LEAST ONE PROCESS COVERED BY SUBCLASS C21D OR C22F OR CLASS C25
    • C23F11/00—Inhibiting corrosion of metallic material by applying inhibitors to the surface in danger of corrosion or adding them to the corrosive agent
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B05—SPRAYING OR ATOMISING IN GENERAL; APPLYING FLUENT MATERIALS TO SURFACES, IN GENERAL
    • B05D—PROCESSES FOR APPLYING FLUENT MATERIALS TO SURFACES, IN GENERAL
    • B05D2506/00—Halogenated polymers
    • B05D2506/10—Fluorinated polymers

Landscapes

  • Chemical & Material Sciences (AREA)
  • Engineering & Computer Science (AREA)
  • Materials Engineering (AREA)
  • Organic Chemistry (AREA)
  • Mechanical Engineering (AREA)
  • Metallurgy (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • General Chemical & Material Sciences (AREA)
  • Life Sciences & Earth Sciences (AREA)
  • Wood Science & Technology (AREA)
  • Physics & Mathematics (AREA)
  • Plasma & Fusion (AREA)
  • Laminated Bodies (AREA)
  • Paints Or Removers (AREA)
  • Chemical Treatment Of Metals (AREA)
  • Application Of Or Painting With Fluid Materials (AREA)
  • Coating By Spraying Or Casting (AREA)
  • Preventing Corrosion Or Incrustation Of Metals (AREA)
  • Heat Treatment Of Articles (AREA)
  • Arc Welding In General (AREA)

Description

本発明は、溶接鋼管用防錆処理液、溶接鋼管の化成処理方法、溶接鋼管および溶接鋼管の成形加工品に関する。 The present invention relates to a rust preventive treatment liquid for welded steel pipes, a chemical conversion treatment method for welded steel pipes, and molded products of welded steel pipes and welded steel pipes.

現在、農業用ビニールハウスの躯体（骨組み）や地中埋設管などの様々な用途において、Ｚｎ系合金めっき鋼板などから造管された溶接鋼管が使用されている。このような溶接鋼管は、そのままでは耐食性や耐変色性などが不十分な場合があるため、有機樹脂を含む化成処理皮膜をその表面に形成されることがある。たとえば、特許文献１には、Ｚｎ系合金めっき鋼板から造管された溶接めっき鋼管の外側の表面に、ウレタン樹脂などの有機樹脂を含む化成処理皮膜（有機樹脂皮膜）をポストコート方式で形成することが記載されている。 Currently, welded steel pipes made from Zn-based alloy-plated steel sheets are used in various applications such as the skeleton (framework) of agricultural greenhouses and underground pipes. Since such a welded steel pipe may have insufficient corrosion resistance and discoloration resistance as it is, a chemical conversion treatment film containing an organic resin may be formed on the surface thereof. For example, in Patent Document 1, a chemical conversion treatment film (organic resin film) containing an organic resin such as urethane resin is formed on the outer surface of a weld-plated steel tube formed from a Zn-based alloy-plated steel sheet by a post-coating method. It is stated that.

ところで、化成処理皮膜の耐候性を向上させるために、化成処理皮膜を構成する有機樹脂として耐候性に優れるフッ素含有樹脂を使用することがある。フッ素含有樹脂組成物は、溶剤系フッ素含有樹脂組成物と水系フッ素含有樹脂組成物とに大別される。従来、耐候性の向上を目的としてフッ素含有樹脂を使用する場合、有機溶剤系フッ素含有樹脂組成物を使用するのが一般的であった。しかしながら、有機溶剤系フッ素含有樹脂組成物には、揮発した有機溶剤の回収などに手間がかかるとの問題がある。 By the way, in order to improve the weather resistance of the chemical conversion treatment film, a fluorine-containing resin having excellent weather resistance may be used as the organic resin constituting the chemical conversion treatment film. Fluorine-containing resin compositions are roughly classified into solvent-based fluorine-containing resin compositions and water-based fluorine-containing resin compositions. Conventionally, when a fluorine-containing resin is used for the purpose of improving weather resistance, it is common to use an organic solvent-based fluorine-containing resin composition. However, the organic solvent-based fluorine-containing resin composition has a problem that it takes time and effort to recover the volatilized organic solvent.

一方、水系フッ素含有樹脂組成物は、有機溶剤系フッ素含有樹脂組成物に比べて取り扱いが容易であり、様々なものが提案されている（たとえば、特許文献２参照）。しかしながら、多くの水系フッ素含有樹脂組成物は、高温での焼き付けを必要とすることが多い（たとえば１８０〜２３０℃、特許文献２参照）。たとえば、ポストコート方式で溶接鋼管の表面に化成処理皮膜を形成する場合、成形加工後の現場では設備の面からこのような高温での焼き付けを行うことが難しいことがある。 On the other hand, the water-based fluorine-containing resin composition is easier to handle than the organic solvent-based fluorine-containing resin composition, and various ones have been proposed (see, for example, Patent Document 2). However, many water-based fluorine-containing resin compositions often require baking at a high temperature (for example, 180 to 230 ° C., see Patent Document 2). For example, when a chemical conversion treatment film is formed on the surface of a welded steel pipe by a post-coating method, it may be difficult to perform such high-temperature baking from the aspect of equipment at the site after the molding process.

低温での焼き付けでも造膜できるように、硬化性部位（有機官能基）を導入した水系フッ素含有樹脂組成物も提案されている（たとえば、特許文献３参照）。しかしながら、有機官能基を利用して硬化させた化成処理皮膜は、硬化部から優先的に耐候劣化してしまうため、屋外で使用すると多孔質状になり、耐水性が低下してしまう。 An aqueous fluorine-containing resin composition having a curable moiety (organic functional group) introduced has also been proposed so that a film can be formed even by baking at a low temperature (see, for example, Patent Document 3). However, the chemical conversion-treated film cured by using an organic functional group preferentially deteriorates in weather resistance from the cured portion, so that when used outdoors, it becomes porous and the water resistance deteriorates.

そこで、特許文献４〜８には、有機官能基ではなく、第４族金属を含む化合物によってフッ素樹脂を架橋させて、フッ素樹脂を含む有機樹脂皮膜の耐水性を高めることができる、化成処理液が記載されている。 Therefore, in Patent Documents 4 to 8, a chemical conversion treatment liquid capable of enhancing the water resistance of the organic resin film containing the fluororesin by cross-linking the fluororesin with a compound containing a Group 4 metal instead of an organic functional group. Is described.

特開２００３−２９３１６５号公報Japanese Unexamined Patent Publication No. 2003-293165 特開昭５７−３８８４５号公報Japanese Unexamined Patent Publication No. 57-38845 特開平５−２０２２６０号公報Japanese Unexamined Patent Publication No. 5-202260 国際公開第２０１１／１５８５１３号International Publication No. 2011/158513 国際公開第２０１１／１５８５１６号International Publication No. 2011/158516 特開２０１２−２１２０７号公報Japanese Unexamined Patent Publication No. 2012-21207 特開２０１２−１７７１４６号公報Japanese Unexamined Patent Publication No. 2012-177146 特開２０１２−１７７１４７号公報Japanese Unexamined Patent Publication No. 2012-177147

前述の通り、溶接鋼管の表面に有機樹脂を含む化成処理皮膜を形成することで、耐食性や耐変色性などを向上させることができる。しかしながら、有機樹脂を含む化成処理皮膜を形成された溶接鋼管は、屋外で使用した場合に耐候性が不十分である場合があった。すなわち、ウレタン樹脂などの多くの有機樹脂は紫外線により劣化してしまうため、化成処理皮膜を形成された溶接鋼管を屋外で使用した場合、表面を被覆する化成処理皮膜が時間の経過とともに失われてしまうおそれがある。このように化成処理皮膜が失われてしまうと、溶接鋼管の表面に腐食や変色などが発生してしまい、美観が損なわれるおそれがある。 As described above, by forming a chemical conversion treatment film containing an organic resin on the surface of a welded steel pipe, corrosion resistance and discoloration resistance can be improved. However, the welded steel pipe on which a chemical conversion treatment film containing an organic resin is formed may have insufficient weather resistance when used outdoors. That is, since many organic resins such as urethane resins are deteriorated by ultraviolet rays, when a welded steel pipe on which a chemical conversion coating is formed is used outdoors, the chemical conversion coating that covers the surface is lost over time. There is a risk that it will end up. If the chemical conversion treatment film is lost in this way, corrosion or discoloration may occur on the surface of the welded steel pipe, which may spoil the aesthetic appearance.

化成処理皮膜の耐候性を向上させる手段として、耐候性に優れる特許文献４〜８に記載のようなフッ素含有樹脂を使用することが考えられる。しかし、溶接鋼管は、屋外の様々な環境で使用されるため、化成処理皮膜の耐候性を高めるのみならず、赤錆の発生をより抑制する（耐食性を高める）ことに対する要望は依然として存在する。また、防錆処理液には、当然ながら、高い保存安定性が望まれる。 As a means for improving the weather resistance of the chemical conversion coating, it is conceivable to use a fluorine-containing resin as described in Patent Documents 4 to 8 having excellent weather resistance. However, since welded steel pipes are used in various outdoor environments, there is still a demand not only to improve the weather resistance of the chemical conversion coating film but also to further suppress the generation of red rust (improve the corrosion resistance). In addition, the rust preventive treatment liquid is, of course, desired to have high storage stability.

本発明は、かかる点に鑑みてなされたものであり、化成処理皮膜の耐候性をより高めることができる溶接鋼管用の防錆処理液、当該処理液により溶接鋼管に化成処理皮膜を形成する方法、ならびに当該処理液により形成された化成処理皮膜を有する溶接鋼管および溶接鋼管の成形加工品を提供することを目的とする。 The present invention has been made in view of this point, and is a rust-preventive treatment liquid for welded steel pipes capable of further enhancing the weather resistance of the chemical conversion treatment film, and a method for forming a chemical conversion treatment film on the welded steel pipe with the treatment liquid. , And a welded steel pipe having a chemical conversion treatment film formed by the treatment liquid, and a molded product of the welded steel pipe.

上記の課題に鑑み、本発明の一態様は、溶接鋼管用防錆処理液に関する。上記端面防錆処理液は、フッ素樹脂を含む有機樹脂と、第４族元素を含む化合物または第４族元素のイオンと、アジピン酸またはフタル酸と炭素数１以上３以下のアルコールとのエステル化合物およびｎ−メチル−２−ピロリドンからなる群から選択される１以上の結合促進剤と、を含み、上記第４族元素を含む化合物または第４族元素のイオンの含有量は、金属換算で０．５ｇ／Ｌ以上６ｇ／Ｌ以下であり、上記第４族元素を含む化合物または第４族元素のイオンの金属換算した含有量と上記結合促進剤の含有量の合計は、２０ｇ／Ｌ以下である。 In view of the above problems, one aspect of the present invention relates to a rust preventive treatment liquid for welded steel pipes. The end face rust preventive treatment liquid is an ester compound of an organic resin containing a fluorine resin, a compound containing a Group 4 element or an ion of a Group 4 element, adipic acid or phthalic acid, and an alcohol having 1 or more and 3 or less carbon atoms. And one or more bond promoters selected from the group consisting of n-methyl-2-pyrrolidone, and the ion content of the compound containing the above Group 4 element or the Group 4 element is 0 in terms of metal. .5 g / L or more and 6 g / L or less, and the total of the metal-equivalent content of the compound containing the Group 4 element or the ion of the Group 4 element and the content of the bond promoter is 20 g / L or less. be.

また、本発明の他の態様は、溶接鋼板の化成処理方法に関する。上記化成処理方法は、鋼板またはめっき鋼板の表面に、溶接鋼管用防錆処理液を付与する工程を含む。上記端面防錆処理液は、フッ素樹脂を含む有機樹脂と、第４族元素を含む化合物または第４族元素のイオンと、アジピン酸またはフタル酸と炭素数１以上３以下のアルコールとのエステル化合物およびｎ−メチル−２−ピロリドンからなる群から選択される１以上の結合促進剤と、を含み、上記第４族元素を含む化合物または第４族元素のイオンの含有量は、金属換算で０．５ｇ／Ｌ以上６ｇ／Ｌ以下であり、上記第４族元素を含む化合物または第４族元素のイオンの金属換算した含有量と上記結合促進剤の含有量の合計は、２０ｇ／Ｌ以下である。 Another aspect of the present invention relates to a method for chemical conversion treatment of a welded steel sheet. The chemical conversion treatment method includes a step of applying a rust preventive treatment liquid for welded steel pipes to the surface of a steel sheet or a plated steel sheet. The end face rust preventive treatment liquid is an ester compound of an organic resin containing a fluorine resin, a compound containing a Group 4 element or an ion of a Group 4 element, adipic acid or phthalic acid, and an alcohol having 1 or more and 3 or less carbon atoms. And one or more bond promoters selected from the group consisting of n-methyl-2-pyrrolidone, and the ion content of the compound containing the above Group 4 element or the Group 4 element is 0 in terms of metal. .5 g / L or more and 6 g / L or less, and the total of the metal-equivalent content of the compound containing the Group 4 element or the ion of the Group 4 element and the content of the bond promoter is 20 g / L or less. be.

また、本発明のさらに他の態様は、溶接鋼管の表面と、溶接部または溶接部を覆う溶射補修層と、の両方の上に、化成処理皮膜を有する溶接鋼管に関する。上記化成処理皮膜は、フッ素樹脂を含む有機樹脂と、第４族元素を含む化合物または第４族元素のイオンと、アジピン酸またはフタル酸と炭素数１以上３以下のアルコールとのエステル化合物およびｎ−メチル−２−ピロリドンからなる群から選択される１以上の結合促進剤と、を含む。 Yet another aspect of the present invention relates to a welded steel pipe having a chemical conversion coating on both the surface of the welded steel pipe and the welded portion or the thermal spray repair layer covering the welded portion. The chemical conversion coating comprises an organic resin containing a fluororesin, a compound containing a Group 4 element or an ion of a Group 4 element, an ester compound of adipic acid or phthalic acid and an alcohol having 1 or more and 3 or less carbon atoms, and n. Includes one or more binding promoters selected from the group consisting of -methyl-2-pyrrolidone.

また、本発明のさらに他の態様は、溶接鋼管の成形加工によって作製された溶接鋼管の成形加工品に関する。上記溶接鋼管の成形加工品は、溶接鋼管の表面と、溶接部または溶接部を覆う溶射補修層と、の両方の上に化成処理皮膜を有し、上記化成処理皮膜は、フッ素樹脂を含む有機樹脂と、第４族元素を含む化合物または第４族元素のイオンと、アジピン酸またはフタル酸と炭素数１以上３以下のアルコールとのエステル化合物およびｎ−メチル−２−ピロリドンからなる群から選択される１以上の結合促進剤と、を含む。 In addition, still another aspect of the present invention relates to a molded product of a welded steel pipe produced by forming a welded steel pipe. The molded product of the welded steel pipe has a chemical conversion treatment film on both the surface of the welded steel pipe and the thermal spray repair layer covering the welded portion or the welded portion, and the chemical conversion treatment film is an organic compound containing a fluororesin. Selected from the group consisting of a resin, a compound containing a Group 4 element or an ion of a Group 4 element, an ester compound of adipic acid or phthalic acid and an alcohol having 1 or more and 3 or less carbon atoms, and n-methyl-2-pyrrolidone. Includes one or more binding promoters that are made.

本発明によれば、化成処理皮膜の耐候性をより高めることができる溶接鋼管用の防錆処理液、当該処理液により溶接鋼管に化成処理皮膜を形成する方法、ならびに当該処理液により形成された化成処理皮膜を有する溶接鋼管および溶接鋼管の成形加工品が提供される。 According to the present invention, a rust-preventive treatment liquid for a welded steel pipe capable of further enhancing the weather resistance of the chemical conversion treatment film, a method for forming a chemical conversion treatment film on a welded steel pipe with the treatment liquid, and the treatment liquid formed. Welded steel pipes having a chemical conversion treatment film and molded products of welded steel pipes are provided.

図１は、本発明の一実施形態に係る溶接めっき鋼板の溶接部周辺の拡大断面図である。FIG. 1 is an enlarged cross-sectional view of a welded portion of a welded galvanized steel sheet according to an embodiment of the present invention.

本発明者らは、鋭意検討の結果、フッ素樹脂を含む有機樹脂および第４族元素を含む化合物または第４族元素のイオンを含む水系処の防錆理液に、特定の化合物（以下、単に「結合促進剤」ともいう。）をさらに含有させて、溶接鋼管用防錆処理液とすることで、溶接鋼管の表面に形成される化成処理皮膜の耐食性がより高まることを見出した。本発明者らは、この耐食性の向上をもたらす作用効果についてさらに検討した結果、上記結合促進剤としてアジピン酸またはフタル酸と炭素数１以上３以下のアルコールとのエステル化合物およびｎ−メチル−２−ピロリドンが使用できることを見出し、さらに、第４族元素を含む化合物または第４族元素のイオンの含有量を、金属換算で０．５ｇ／Ｌ以上６ｇ／Ｌ以下とし、第４族元素を含む化合物または第４族元素のイオンの金属換算した含有量と結合促進剤の含有量の合計を、２０ｇ／Ｌ以下とすることで、処理液の保存性の低下を抑制しつつ、耐食性を高めることができることを見出し、もって本発明を完成させた。 As a result of diligent studies, the present inventors have added a specific compound (hereinafter, simply referred to as "simply") to an organic resin containing a fluororesin and a compound containing a Group 4 element or an aqueous rust preventive solution containing an ion of a Group 4 element. It has been found that the corrosion resistance of the chemical conversion coating formed on the surface of the welded steel pipe is further enhanced by further adding (also referred to as “bonding accelerator”) to prepare a rust preventive treatment liquid for welded steel pipes. As a result of further studying the action and effect that bring about the improvement of the corrosion resistance, the present inventors have made an ester compound of adipic acid or phthalic acid and an alcohol having 1 or more and 3 or less carbon atoms as the above-mentioned bond promoter, and n-methyl-2-. It was found that pyrrolidone can be used, and further, the compound containing a Group 4 element or the ion content of the Group 4 element is set to 0.5 g / L or more and 6 g / L or less in terms of metal, and the compound containing a Group 4 element is used. Alternatively, by setting the total of the metal-equivalent content of the group 4 element ion and the content of the bond promoter to 20 g / L or less, it is possible to improve the corrosion resistance while suppressing the deterioration of the storage stability of the treatment liquid. He found out what he could do and completed the present invention.

つまり、上記結合促進剤は、通常はエマルションとして防錆処理液中に存在するフッ素樹脂を、軟質化することができる。上記結合促進剤によって軟質化したフッ素樹脂は、より融着しやすくなり、耐水性がより高い化成処理皮膜を形成するため、化成処理皮膜の耐候性がより高まると考えられる。 That is, the bond accelerator can soften the fluororesin that normally exists as an emulsion in the rust preventive treatment liquid. It is considered that the fluororesin softened by the bond accelerator forms a chemical conversion-treated film having higher water resistance and is more easily fused, so that the weather resistance of the chemical conversion-treated film is further enhanced.

また、上記第４族元素を含む化合物または第４族元素のイオンは、フッ素樹脂の密着性を高め、かつ、低温乾燥でも化成処理皮膜の耐水性を高めることができる。しかし、上記第４族元素を含む化合物または第４族元素のイオンと結合促進剤との含有量の合計が多くなりすぎると、処理液の保存性が低下するおそれがある。これに対し、第４族元素を含む化合物または第４族元素のイオンの含有量を、金属換算で２ｇ／Ｌ以上６ｇ／Ｌ以下とし、第４族元素を含む化合物または第４族元素のイオンの金属換算した含有量と結合促進剤の含有量の合計を、２０ｇ／Ｌ以下とすることで、これらによる密着性および耐水性の向上と、保存性の低下の抑制と、を両立させることができる。 Further, the compound containing the Group 4 element or the ion of the Group 4 element can enhance the adhesion of the fluororesin and enhance the water resistance of the chemical conversion coating even when dried at low temperature. However, if the total content of the compounds containing the Group 4 elements or the ions of the Group 4 elements and the bond promoter becomes too large, the storage stability of the treatment liquid may deteriorate. On the other hand, the ion content of the compound containing the Group 4 element or the Group 4 element is set to 2 g / L or more and 6 g / L or less in terms of metal, and the ion of the compound containing the Group 4 element or the Group 4 element. By setting the total of the metal-equivalent content and the content of the bond promoter to 20 g / L or less, it is possible to achieve both improvement of adhesion and water resistance and suppression of deterioration of storage stability. can.

１．防錆処理液
上記防錆処理液は、フッ素樹脂を含む有機樹脂、第４族元素を含む化合物または第４族元素のイオンおよび上記結合促進剤を含む。上記防錆処理液は、エッチング剤などのその他の成分をさらに含んでもよい。 1. 1. Anti-corrosion treatment liquid The above-mentioned rust prevention treatment liquid contains an organic resin containing a fluororesin, a compound containing a Group 4 element or an ion of a Group 4 element, and the above-mentioned bond promoter. The rust preventive treatment liquid may further contain other components such as an etching agent.

１−１．有機樹脂
有機樹脂は、フッ素樹脂を含む有機樹脂である。フッ素樹脂は、化成処理皮膜の耐候性（耐紫外線性および耐光性など）および耐食性（赤錆の防止など）を高めることができる。なお、有機樹脂は、化成処理皮膜の耐候性および耐食性を顕著に低下させない限りにおいて、フッ素樹脂以外の樹脂を含んでもよい。 1-1. Organic resin The organic resin is an organic resin containing a fluororesin. The fluororesin can enhance the weather resistance (ultraviolet resistance, light resistance, etc.) and corrosion resistance (prevention of red rust, etc.) of the chemical conversion treatment film. The organic resin may contain a resin other than the fluororesin as long as the weather resistance and corrosion resistance of the chemical conversion treatment film are not significantly reduced.

フッ素樹脂は、溶剤系フッ素樹脂と水系フッ素樹脂に大別される。これらのうち、揮発した溶剤の回収が問題とならない防錆処理液に用いることが容易な、水系フッ素樹脂を用いることが好ましい。 Fluororesin is roughly classified into solvent-based fluororesin and water-based fluororesin. Of these, it is preferable to use an aqueous fluororesin that can be easily used as a rust preventive treatment liquid in which recovery of the volatile solvent does not pose a problem.

水系フッ素樹脂とは、親水性官能基を有するフッ素樹脂を意味する。親水性官能基の好ましい例には、カルボキシル基およびスルホン酸基、ならびにこれらの塩などが含まれる。カルボキシル基またはスルホン酸基の塩の例には、アンモニウム塩、アミン塩、およびアルカリ金属塩などが含まれる。 The aqueous fluororesin means a fluororesin having a hydrophilic functional group. Preferred examples of hydrophilic functional groups include carboxyl groups and sulfonic acid groups, salts thereof and the like. Examples of salts of carboxyl or sulfonic acid groups include ammonium salts, amine salts, alkali metal salts and the like.

水系フッ素樹脂は、親水性官能基の量が０.０５質量％以上５質量％以下の量であることが好ましい。親水性官能基の量が０.０５質量％以上５質量％以下の量であるフッ素樹脂は、乳化剤をほとんど使用せずとも、水系エマルションとすることができる。乳化剤をほとんど含まない化成処理皮膜は、耐水性に優れた化成処理皮膜とすることができる。 The amount of the hydrophilic functional group in the aqueous fluororesin is preferably 0.05% by mass or more and 5% by mass or less. A fluororesin having a hydrophilic functional group content of 0.05% by mass or more and 5% by mass or less can be made into an aqueous emulsion with almost no use of an emulsifier. A chemical conversion-treated film containing almost no emulsifier can be a chemical conversion-treated film having excellent water resistance.

水系フッ素樹脂中の親水性官能基の含有量は、水系フッ素樹脂に含まれる親水性官能基の総モル質量を、水系フッ素樹脂の数平均分子量で除して求めればよい。カルボキシル基のモル質量は４５であり、スルホン酸基のモル質量は８１であるので、水系フッ素樹脂に含まれるカルボキシル基およびスルホン酸基それぞれの数を求め、それぞれにモル質量を乗じることで、水系フッ素樹脂に含まれる親水性官能基の総モル質量が求まる。水系フッ素樹脂の数平均分子量はＧＰＣで測定され得る。 The content of the hydrophilic functional groups in the aqueous fluororesin may be determined by dividing the total molar mass of the hydrophilic functional groups contained in the aqueous fluororesin by the number average molecular weight of the aqueous fluororesin. Since the molar mass of the carboxyl group is 45 and the molar mass of the sulfonic acid group is 81, the number of each of the carboxyl group and the sulfonic acid group contained in the aqueous fluororesin is obtained, and the molar mass is multiplied by each to obtain the molar mass of the aqueous system. The total molar mass of the hydrophilic functional groups contained in the fluororesin can be obtained. The number average molecular weight of the aqueous fluororesin can be measured by GPC.

水系フッ素樹脂におけるカルボキシル基は、鋼板またはめっき層（または下地化成処理皮膜）の表面と水素結合などを形成して、化成処理皮膜と鋼板またはめっき層（または下地化成処理皮膜）表面との密着性の向上に寄与するが、Ｈ＋が解離しにくいため第４族元素を含む化合物または第４族元素のイオンとの架橋反応が生じにくい。一方、水系フッ素樹脂におけるスルホン酸基は、Ｈ＋が解離しやすいため第４族元素を含む化合物または第４族元素のイオンとの架橋反応が生じやすいものの、一方で第４族元素を含む化合物または第４族元素のイオンと架橋反応せずに未反応のまま皮膜中に残存すると、水分子の吸着作用が強いため化成処理皮膜の耐水性を著しく低下させてしまうおそれがある。したがって、それぞれの特徴を活かすべく、水系フッ素樹脂には、カルボキシル基およびスルホン酸基の両方を含むことが好ましい。この場合、カルボキシル基とスルホン酸基との比率は、カルボキシル基／スルホン酸基のモル比で５以上６０以下の範囲内が好ましい。 The carboxyl group in the aqueous fluororesin forms a hydrogen bond with the surface of the steel plate or plating layer (or base chemical conversion treatment film), and the adhesion between the chemical conversion treatment film and the surface of the steel plate or plating layer (or base chemical conversion treatment film) However, since H + is less likely to be dissociated, a cross-linking reaction with a compound containing a Group 4 element or an ion of a Group 4 element is unlikely to occur. On the other hand, the sulfonic acid group in the aqueous fluororesin tends to dissociate H + , so that a compound containing a Group 4 element or a cross-linking reaction with an ion of a Group 4 element is likely to occur, but on the other hand, a compound containing a Group 4 element. Alternatively, if it remains unreacted in the film without undergoing a cross-linking reaction with the ions of Group 4 elements, the water resistance of the chemical conversion-treated film may be significantly reduced due to the strong adsorption action of water molecules. Therefore, in order to utilize the respective characteristics, it is preferable that the aqueous fluororesin contains both a carboxyl group and a sulfonic acid group. In this case, the ratio of the carboxyl group to the sulfonic acid group is preferably in the range of 5 or more and 60 or less in terms of the molar ratio of the carboxyl group / sulfonic acid group.

水系フッ素樹脂の数平均分子量は、１０００以上が好ましく、１万以上がより好ましく、２０万以上が特に好ましい。 The number average molecular weight of the aqueous fluororesin is preferably 1000 or more, more preferably 10,000 or more, and particularly preferably 200,000 or more.

水系フッ素樹脂の数平均分子量の下限が上記値であると、化成処理皮膜の透水性および耐水性を十分に高めることができ、湿気や腐食性ガスなどが化成処理皮膜を貫通することによる鋼板またはめっき鋼板の腐食を抑制することができる。また、水系フッ素樹脂の数平均分子量の下限が上記値であると、光エネルギーなどの作用により発生したラジカルがポリマー鎖の末端に作用しにくいため、水などの相乗作用により水系フッ素樹脂が加水分解されてしまうことによる、化成処理皮膜の劣化を抑制することもできる。水系フッ素樹脂の分子量を大きくすることにより、分子間力が強くなり、化成処理皮膜の凝集力が高まるため、化成処理皮膜の耐水性をより高めることができる。また、水系フッ素樹脂の分子量を大きくすることにより、水系フッ素樹脂の主鎖における原子間の結合を安定化して、水系フッ素樹脂の加水分解による化成処理皮膜の劣化も生じにくくなる。 When the lower limit of the number average molecular weight of the aqueous fluororesin is the above value, the water permeability and water resistance of the chemical conversion coating can be sufficiently increased, and the steel sheet or the steel sheet due to moisture, corrosive gas, etc. penetrating the chemical conversion coating. Corrosion of plated steel sheet can be suppressed. Further, when the lower limit of the number average molecular weight of the aqueous fluororesin is the above value, the radical generated by the action of light energy or the like does not easily act on the end of the polymer chain, so that the aqueous fluororesin is hydrolyzed by the synergistic action of water or the like. It is also possible to suppress the deterioration of the chemical conversion treatment film due to the fluorination. By increasing the molecular weight of the aqueous fluororesin, the intramolecular force becomes stronger and the cohesive force of the chemical conversion treatment film increases, so that the water resistance of the chemical conversion treatment film can be further improved. Further, by increasing the molecular weight of the aqueous fluororesin, the bonds between atoms in the main chain of the aqueous fluororesin are stabilized, and the deterioration of the chemical conversion treatment film due to the hydrolysis of the aqueous fluororesin is less likely to occur.

一方で、水系フッ素樹脂の数平均分子量は、２００万以下が好ましい。水系フッ素樹脂の数平均分子量の上限が２００万以下であれば、防錆処理液のゲル化などが生じにくく、防錆処理液の保存安定性がより高まる。 On the other hand, the number average molecular weight of the aqueous fluororesin is preferably 2 million or less. When the upper limit of the number average molecular weight of the aqueous fluororesin is 2 million or less, gelation of the rust preventive treatment liquid is unlikely to occur, and the storage stability of the rust preventive treatment liquid is further enhanced.

水系フッ素樹脂は、化成処理皮膜の耐候性および耐食性をより高める観点から、上記フッ素樹脂の全質量に対して６質量％以上のフッ素（Ｆ）原子を含むことが好ましく、８質量％以上のフッ素（Ｆ）原子を含むことがより好ましい。また、水系フッ素樹脂は、塗料化を容易にし、かつ、化成処理皮膜の密着性および乾燥性をより高める観点から、前記フッ素樹脂の全質量に対して２０質量％以下のフッ素（Ｆ）原子を含むことが好ましい。水系フッ素樹脂中のフッ素（Ｆ）原子の含有量は、蛍光Ｘ線分析装置を用いることで測定することができる。 From the viewpoint of further enhancing the weather resistance and corrosion resistance of the chemical conversion coating, the aqueous fluororesin preferably contains 6% by mass or more of fluorine (F) atoms with respect to the total mass of the fluororesin, and 8% by mass or more of fluorine. (F) It is more preferable to contain an atom. Further, the aqueous fluororesin contains 20% by mass or less of fluorine (F) atoms with respect to the total mass of the fluororesin from the viewpoint of facilitating the coating and further improving the adhesion and drying property of the chemical conversion treatment film. It is preferable to include it. The content of fluorine (F) atoms in the aqueous fluororesin can be measured by using a fluorescent X-ray analyzer.

水系フッ素樹脂としては、フッ素含有オレフィン樹脂であることが好ましい。フッ素含有オレフィン樹脂の例には、フルオロオレフィンと親水性官能基含有モノマーとの共重合体が含まれる。 The aqueous fluororesin is preferably a fluorine-containing olefin resin. Examples of fluorine-containing olefin resins include copolymers of fluoroolefins and hydrophilic functional group-containing monomers.

上記フルオロオレフィンの例には、テトラフルオロエチレン、トリフルオロエチレン、クロロトリフルオロエチレン、ヘキサフルオロプロピレン、フッ化ビニル、フッ化ビニリデン、ペンタフルオロプロピレン、２，２，３，３−テトラフルオロプロピレン、３，３，３−トリフルオロプロピレン、ブロモトリフルオロエチレン、１−クロロ−１，２−ジフルオロエチレン、および１，１−ジクロロ−２，２−ジフルオロエチレンなどが含まれる。これらのフルオロオレフィンは、単独で使用されてもよいし、２種類以上を組み合わせて使用されてもよい。耐紫外線性をより高める観点からは、これらのフルオロオレフィンの中でも、テトラフルオロエチレンおよびヘキサフルオロプロピレンなどを含むパーフルオロオレフィン、ならびにフッ化ビニリデンなどが好ましい。なお、塩素イオンによる腐食を抑制する観点からは、クロロトリフルオロエチレンなどの塩素を含むフルオロオレフィンの含有量は少ない（たとえば０．１モル％以下）ことが好ましい。 Examples of the above fluoroolefins include tetrafluoroethylene, trifluoroethylene, chlorotrifluoroethylene, hexafluoropropylene, vinyl fluoride, vinylidene fluoride, pentafluoropropylene, 2,2,3,3-tetrafluoropropylene, 3 , 3,3-Trifluoropropylene, bromotrifluoroethylene, 1-chloro-1,2-difluoroethylene, and 1,1-dichloro-2,2-difluoroethylene and the like. These fluoroolefins may be used alone or in combination of two or more. From the viewpoint of further enhancing the ultraviolet resistance, among these fluoroolefins, perfluoroolefins containing tetrafluoroethylene, hexafluoropropylene and the like, vinylidene fluoride and the like are preferable. From the viewpoint of suppressing corrosion due to chlorine ions, it is preferable that the content of fluoroolefin containing chlorine such as chlorotrifluoroethylene is small (for example, 0.1 mol% or less).

上記親水性官能基含有モノマーの例には、公知のカルボキシル基含有モノマーおよびスルホン酸基含有モノマーが含まれる。これらの親水性官能基含有モノマーは、単独で使用されてもよいし、２種類以上を組み合わせて使用されてもよい。 Examples of the hydrophilic functional group-containing monomer include known carboxyl group-containing monomers and sulfonic acid group-containing monomers. These hydrophilic functional group-containing monomers may be used alone or in combination of two or more.

上記カルボキシル基含有モノマーの一例としては、以下の式（１）に示される不飽和カルボン酸、およびこれらのエステルまたは酸無水物などを含む不飽和カルボン酸類が挙げられる。 Examples of the carboxyl group-containing monomer include unsaturated carboxylic acids represented by the following formula (1), and unsaturated carboxylic acids including esters or acid anhydrides thereof.

Figure 0006962216
（式中、Ｒ１、Ｒ２およびＲ３は、独立に、水素原子、アルキル基、カルボキシル基またはエステル基を示す。ｎは０〜２０の整数である。）
Figure 0006962216
 (In the formula, R 1 , R 2 and R 3 independently represent a hydrogen atom, an alkyl group, a carboxyl group or an ester group. N is an integer of 0 to 20.)

上記式（１）に示される不飽和カルボン酸の具体例には、アクリル酸、メタクリル酸、ビニル酢酸、クロトン酸、桂皮酸、イタコン酸、イタコン酸モノエステル、マレイン酸、マレイン酸モノエステル、フマル酸、フマル酸モノエステル、５−ヘキセン酸、５−ヘプテン酸、６−ヘプテン酸、７−オクテン酸、８−ノネン酸、９−デセン酸、１０−ウンデシレン酸、１１−ドデシレン酸、１７−オクタデシレン酸、およびオレイン酸などが含まれる。 Specific examples of the unsaturated carboxylic acid represented by the above formula (1) include acrylic acid, methacrylic acid, vinyl acetic acid, crotonic acid, cinnamic acid, itaconic acid, itaconic acid monoester, maleic acid, maleic acid monoester, and fumal. Acid, fumaric acid monoester, 5-hexenoic acid, 5-heptenoic acid, 6-heptenoic acid, 7-octenoic acid, 8-nonenic acid, 9-decenoic acid, 10-undecylene acid, 11-dodecylene acid, 17-octadecilene Acids, oleic acid and the like are included.

上記カルボキシル基含有モノマーの別の例としては、以下の式（２）に示されるカルボキシル基含有ビニルエーテルモノマーが挙げられる。 Another example of the above-mentioned carboxyl group-containing monomer is a carboxyl group-containing vinyl ether monomer represented by the following formula (2).

Figure 0006962216
（式中、Ｒ４およびＲ５は、独立に、飽和または不飽和の直鎖または環状アルキル基を示す。ｎは０または１である。ｍは０または１である。）
Figure 0006962216
 (In the formula, R 4 and R 5 independently represent saturated or unsaturated linear or cyclic alkyl groups; n is 0 or 1. m is 0 or 1.)

上記式（２）に示されるカルボキシル基含有ビニルエーテルモノマーの具体例には、３−（２−アリロキシエトキシカルボニル）プロピオン酸、３−（２−アリロキシブトキシカルボニル）プロピオン酸、３−（２−ビニロキシエトキシカルボニル）プロピオン酸、および３−（２−ビニロキシブトキシカルボニル）プロピオン酸などが含まれる。 Specific examples of the carboxyl group-containing vinyl ether monomer represented by the above formula (2) include 3- (2-aryloxyethoxycarbonyl) propionic acid, 3- (2-aryloxybutoxycarbonyl) propionic acid, and 3- (2-). Includes vinyloxyethoxycarbonyl) propionic acid, 3- (2-vinyloxybutoxycarbonyl) propionic acid, and the like.

上記スルホン酸基含有モノマーの具体例としては、ビニルスルホン酸、アリルスルホン酸、メタリルスルホン酸、スチレンスルホン酸、２−アクリルアミド−２−メチルプロパンスルホン酸、２−メタクリロイルオキシエタンスルホン酸、３−メタクリロイルオキシプロパンスルホン酸、４−メタクリロイルオキシブタンスルホン酸、３−メタクリロイルオキシ−２−ヒドロキシプロパンスルホン酸、３−アクリロイルオキシプロパンスルホン酸、アリルオキシベンゼンスルホイン酸、メタリルオキシベンゼンスルホン酸、イソプレンスルホン酸、および３−アリロキシ−２−ヒドロキシプロパンスルホン酸などが挙げられる。 Specific examples of the sulfonic acid group-containing monomer include vinyl sulfonic acid, allyl sulfonic acid, metharyl sulfonic acid, styrene sulfonic acid, 2-acrylamide-2-methylpropane sulfonic acid, 2-methacryloyloxyetane sulfonic acid, 3-. Methacryloyloxypropanesulfonic acid, 4-methacryloyloxybutanesulfonic acid, 3-methacryloyloxy-2-hydroxypropanesulfonic acid, 3-acryloyloxypropanesulfonic acid, allyloxybenzenesulfonic acid, metallicyloxybenzenesulfonic acid, isoprenesulfon Acids and 3-allyloxy-2-hydroxypropanesulfonic acid can be mentioned.

上記フルオロオレフィンと親水性官能基含有モノマーとの共重合体には、必要に応じて、共重合可能な他のモノマーがさらに共重合されていてもよい。上記共重合可能な他のモノマーとしては、カルボン酸ビニルエステル類、アルキルビニルエーテル類、および非フッ素系オレフィン類などが挙げられる。 If necessary, another copolymerizable monomer may be further copolymerized with the copolymer of the fluoroolefin and the hydrophilic functional group-containing monomer. Examples of the other copolymerizable monomer include carboxylic acid vinyl esters, alkyl vinyl ethers, and non-fluorinated olefins.

上記カルボン酸ビニルエステル類は、上記水系フッ素樹脂の相溶性および化成処理皮膜の光沢を向上させたり、ガラス転移温度を上昇させたりすることができる。上記カルボン酸ビニルエステル類の例には、酢酸ビニル、プロピオン酸ビニル、酪酸ビニル、イソ酪酸ビニル、ピバリン酸ビニル、カプロン酸ビニル、バーサチック酸ビニル、ラウリン酸ビニル、ステアリン酸ビニル、シクロヘキシルカルボン酸ビニル、安息香酸ビニル、およびパラ−ｔ−ブチル安息香酸ビニルなどが含まれる。 The carboxylic acid vinyl esters can improve the compatibility of the aqueous fluororesin and the gloss of the chemical conversion treatment film, and can raise the glass transition temperature. Examples of the above carboxylic acid vinyl esters include vinyl acetate, vinyl propionate, vinyl butyrate, vinyl isobutyrate, vinyl pivalate, vinyl caproate, vinyl versatic acid, vinyl laurate, vinyl stearate, vinyl cyclohexylcarboxylic acid, and the like. Includes vinyl benzoate, parat-butyl vinyl benzoate, and the like.

上記アルキルビニルエーテル類は、化成処理皮膜の光沢および柔軟性を向上させることができる。上記アルキルビニルエーテル類の例には、メチルビニルエーテル、エチルビニルエーテル、およびブチルビニルエーテルなどが含まれる。 The alkyl vinyl ethers can improve the gloss and flexibility of the chemical conversion coating. Examples of the alkyl vinyl ethers include methyl vinyl ether, ethyl vinyl ether, butyl vinyl ether and the like.

上記非フッ素系オレフィン類は、化成処理皮膜の可撓性を向上させることができる。上記非フッ素系オレフィン類の例には、エチレン、プロピレン、ｎ−ブテン、およびイソブテンなどが含まれる。 The non-fluorine-based olefins can improve the flexibility of the chemical conversion treatment film. Examples of the non-fluorinated olefins include ethylene, propylene, n-butene, isobutene and the like.

たとえば、上記モノマーを乳化重合法で共重合させることで、親水性官能基を有するフルオロオレフィン共重合体のエマルションを得ることができる。このとき、フルオロオレフィン共重合体が０.０５質量％以上５質量％以下の量の親水性官能基を有するように、原料モノマー組成物におけるフルオロオレフィンの量を調整することで、乳化剤をほとんど使用せずにフルオロオレフィン共重合体の水系エマルションを製造することができる。乳化剤をほとんど含有しない（１質量％以下）フルオロオレフィン共重合体のエマルションを用いて形成された化成処理皮膜は、乳化剤がほとんど含まれないため、乳化剤の残留による耐水性の劣化がほとんど見られず、優れた耐水性を発揮する。 For example, by copolymerizing the above-mentioned monomers by an emulsion polymerization method, an emulsion of a fluoroolefin copolymer having a hydrophilic functional group can be obtained. At this time, most of the emulsifiers are used by adjusting the amount of fluoroolefin in the raw material monomer composition so that the fluoroolefin copolymer has a hydrophilic functional group in an amount of 0.05% by mass or more and 5% by mass or less. An aqueous emulsion of a fluoroolefin copolymer can be produced without this. Since the chemical conversion-treated film formed by using an emulsion of a fluoroolefin copolymer containing almost no emulsifier (1% by mass or less) contains almost no emulsifier, almost no deterioration in water resistance due to residual emulsifier is observed. Demonstrates excellent water resistance.

上述のような方法で作製したフッ素樹脂は、防錆処理液中でも粒子状で存在すると考えられる。フッ素樹脂のエマルションの平均粒径は、５０ｎｍ以上３００ｎｍ以下であることが好ましい。エマルションの平均粒径を５０ｎｍ以上とすることで、防錆処理液の保存安定性を高めることができる。また、エマルションの平均粒径を３００ｎｍ以下とすることで、エマルションの表面積を増やして互いに融着しやすくさせ、低温（たとえば５５℃）で焼き付けたときの造膜をより容易にできる。たとえば、乳化重合法でエマルションを調製する際に、せん断速度や攪拌時間を最適化することで、エマルションの平均粒径を上記範囲内とすることができる。 It is considered that the fluororesin produced by the above method exists in the form of particles even in the rust preventive treatment liquid. The average particle size of the fluororesin emulsion is preferably 50 nm or more and 300 nm or less. By setting the average particle size of the emulsion to 50 nm or more, the storage stability of the rust preventive treatment liquid can be improved. Further, by setting the average particle size of the emulsion to 300 nm or less, the surface area of the emulsion is increased to facilitate fusion with each other, and film formation when baked at a low temperature (for example, 55 ° C.) can be facilitated. For example, when preparing an emulsion by an emulsion polymerization method, the average particle size of the emulsion can be kept within the above range by optimizing the shear rate and the stirring time.

防錆処理液中のフッ素樹脂の含有量は、水１００質量部に対して、１０質量部以上７０質量部以下であることが好ましい。フッ素樹脂の含有量が１０質量部以上であると、乾燥過程において多量の水の蒸発することによる、化成処理皮膜の成膜性および緻密性の低下がより生じにくい。一方、フッ素樹脂の含有量が７０質量部以下であると、防錆処理液の保存安定性がより高まる。 The content of the fluororesin in the rust preventive treatment liquid is preferably 10 parts by mass or more and 70 parts by mass or less with respect to 100 parts by mass of water. When the content of the fluororesin is 10 parts by mass or more, the film-forming property and the denseness of the chemical conversion coating film are less likely to be deteriorated due to the evaporation of a large amount of water in the drying process. On the other hand, when the content of the fluororesin is 70 parts by mass or less, the storage stability of the rust preventive treatment liquid is further enhanced.

また、防錆処理液中のフッ素樹脂の含有量は、固形分（水その他の溶媒を除いた成分）の合計量に対して、７０質量％以上９９質量％以下であることが好ましい。 The content of the fluororesin in the rust preventive treatment liquid is preferably 70% by mass or more and 99% by mass or less with respect to the total amount of solid content (components excluding water and other solvents).

１−２．第４族元素を含む化合物または第４族元素のイオン
第４族元素を含む化合物または第４族元素のイオンは、フッ素樹脂、特には水系フッ素樹脂中のカルボキシル基やスルホン酸基などの官能基と反応しやすく、水系フッ素樹脂の硬化または架橋反応を促進する。そのため、第４族元素を含む化合物または第４族元素のイオンは、フッ素樹脂の密着性を高め、かつ、低温乾燥でも化成処理皮膜の耐水性を向上させることができる。 1-2. Compounds containing Group 4 elements or ions of Group 4 elements Ions of compounds containing Group 4 elements or Group 4 elements are functional groups such as carboxyl groups and sulfonic acid groups in fluororesins, especially aqueous fluororesins. It easily reacts with and promotes the curing or cross-linking reaction of the aqueous fluororesin. Therefore, the compound containing the Group 4 element or the ion of the Group 4 element can enhance the adhesion of the fluororesin and improve the water resistance of the chemical conversion coating even when dried at low temperature.

第４族元素を含む化合物は、４Ａ族金属の酸素酸塩、フッ化物、水酸化物、有機酸塩、炭酸塩、過酸化塩、アンモニウム塩、アルカリ金属塩、およびアルカリ土類金属塩などとすることができる。なお、酸素酸塩は、酸素と別の元素とを有する酸（炭酸や硫酸など）との塩を意味する。酸素酸塩の例には、水素酸塩、炭酸塩、硫酸塩などが含まれる。第４族元素のイオンの例には、上記化合物に由来する、第４族元素のイオンが含まれる。 Compounds containing Group 4 elements include group 4A metal oxidates, fluorides, hydroxides, organic acid salts, carbonates, peroxides, ammonium salts, alkali metal salts, alkaline earth metal salts and the like. can do. The oxygen salt means a salt of oxygen and an acid (carbonic acid, sulfuric acid, etc.) having another element. Examples of oxidates include hydrides, carbonates, sulfates and the like. Examples of Group 4 element ions include Group 4 element ions derived from the above compounds.

上記第４族元素を含む化合物または第４族元素のイオンの例には、チタン（Ｔｉ）化合物、ジルコニウム（Ｚｒ）化合物およびハフニウム（Ｈｆ）化合物が含まれる。これらのうち、後述する光触媒による耐候性の低下を抑制する観点からは、ジルコニウム化合物が好ましい。 Examples of the compound containing the Group 4 element or the ion of the Group 4 element include a titanium (Ti) compound, a zirconium (Zr) compound and a hafnium (Hf) compound. Of these, a zirconium compound is preferable from the viewpoint of suppressing a decrease in weather resistance due to a photocatalyst described later.

第４族元素を含む化合物または第４族元素のイオンは、メラミン樹脂とは異なり、エステル結合やホルムエーテル結合などが酸化および加水分解などすることによる化成処理皮膜の耐候劣化を生じにくい。また、第４族元素を含む化合物または第４族元素のイオンは、メラミン樹脂とは異なり、酸性雨に含まれる硫酸イオンや硝酸イオンなどの酸性物質によって架橋構造が切断されることによる化成処理皮膜の耐候劣化も生じにくい。 Unlike melamine resins, compounds containing Group 4 elements or ions of Group 4 elements are less likely to cause weather resistance deterioration of the chemical conversion-treated film due to oxidation and hydrolysis of ester bonds and form ether bonds. Further, unlike the melamine resin, the compound containing the Group 4 element or the ion of the Group 4 element is a chemical conversion film formed by cutting the crosslinked structure by an acidic substance such as sulfate ion or nitrate ion contained in acid rain. Weather resistance deterioration is also unlikely to occur.

また、第４族元素を含む化合物または第４族元素のイオンは、イソシアネート樹脂を用いた架橋部分に形成されるウレタン結合よりも強い結合力でフッ素樹脂を架橋させるため、架橋構造の切断による耐候劣化の進行もより生じにくい。 Further, since the compound containing the Group 4 element or the ion of the Group 4 element crosslinks the fluororesin with a stronger bonding force than the urethane bond formed in the crosslinked portion using the isocyanate resin, the weather resistance due to the cutting of the crosslinked structure The progress of deterioration is less likely to occur.

また、第４族元素を含む化合物または第４族元素のイオンは、化成処理皮膜の皮膜密着性、耐水性および耐変色性も向上させる。たとえば、Ａｌ含有Ｚｎ系合金めっき鋼板の表面に第４族元素を含む化合物または第４族元素のイオンを含む防錆処理液で化成処理皮膜を形成させると、めっき鋼板の表面に存在する強固なＡｌ酸化物による皮膜密着性の低下を抑制することができる。また、Ａｌ含有Ｚｎ系合金めっき鋼板の表面に第４族元素を含む化合物または第４族元素のイオンを含む防錆処理液で化成処理皮膜を形成させると、エッチング反応などにより溶出したＡｌイオンと第４族元素を含む化合物または第４族元素のイオンとが反応して生成した反応生成物が、めっき層と化成処理皮膜の界面に濃化して、めっき鋼板の初期の耐食性および耐変色性を向上させる。 Further, the compound containing the Group 4 element or the ion of the Group 4 element also improves the film adhesion, water resistance and discoloration resistance of the chemical conversion treatment film. For example, when a chemical conversion treatment film is formed on the surface of an Al-containing Zn-based alloy-plated steel sheet with a compound containing a Group 4 element or a rust-preventive treatment liquid containing ions of a Group 4 element, the surface of the plated steel sheet is strong. It is possible to suppress a decrease in film adhesion due to Al oxide. Further, when a chemical conversion treatment film is formed on the surface of an Al-containing Zn-based alloy plated steel sheet with a compound containing a Group 4 element or a rust-preventive treatment liquid containing ions of a Group 4 element, Al ions eluted by an etching reaction or the like are formed. The reaction product generated by the reaction of the compound containing the Group 4 element or the ion of the Group 4 element is concentrated at the interface between the plating layer and the chemical conversion coating, and the initial corrosion resistance and discoloration resistance of the plated steel sheet are improved. Improve.

防錆処理液中の第４族元素を含む化合物または第４族元素のイオンの金属換算での含有量は、０．５ｇ／Ｌ以上６．０ｇ／Ｌ以下である。水系フッ素樹脂を十分に架橋させて化成処理皮膜の密着性をより高める観点からは、第４族元素を含む化合物または第４族元素のイオンの含有量は、０．５ｇ／Ｌ以上であればよいが、１ｇ／Ｌ以上であることがより好ましく、２．０ｇ／Ｌ以上であることがさらに好ましい。なお、溶接鋼管を表面処理するときは、防錆処理液の乾燥性を高めるために塗布前の板温を高くしたり、塗布後に乾燥設備によって防錆処理液を乾燥させたりする。これらによっても水系フッ素樹脂の硬化または架橋反応は促進されるため、防錆処理液中の第４族元素を含む化合物または第４族元素のイオンの含有量は、６．０ｇ／Ｌ以下であっても十分である。防錆処理液中の第４族元素を含む化合物または第４族元素のイオンの金属換算での含有量は、蛍光Ｘ線分析装置を用いて測定することができる。 The metal-equivalent content of the compound containing the Group 4 element or the ion of the Group 4 element in the rust preventive treatment liquid is 0.5 g / L or more and 6.0 g / L or less. From the viewpoint of sufficiently cross-linking the aqueous fluororesin to further enhance the adhesion of the chemical conversion treatment film, if the compound containing the Group 4 element or the ion content of the Group 4 element is 0.5 g / L or more. It is preferable, but it is more preferably 1 g / L or more, and further preferably 2.0 g / L or more. When surface-treating a welded steel pipe, the plate temperature before coating is raised in order to improve the drying property of the rust-preventing liquid, or the rust-preventing liquid is dried by a drying facility after coating. Since the curing or cross-linking reaction of the aqueous fluororesin is also promoted by these, the ion content of the compound containing the Group 4 element or the Group 4 element in the rust preventive treatment liquid is 6.0 g / L or less. Is enough. The metal-equivalent content of the compound containing the Group 4 element or the ion of the Group 4 element in the rust preventive treatment liquid can be measured using a fluorescent X-ray analyzer.

１−３．結合促進剤
結合促進剤は、防錆処理液中に存在するフッ素樹脂を軟質化することができる。上記結合促進剤によって軟質化したフッ素樹脂は、エマルションを構成する粒子同士がより密に融着しやすくなり、より水を浸透しにくい化成処理皮膜を形成する。そのため、結合促進剤を含む上記防錆処理液から形成された化成処理皮膜は赤錆を発生させにくくなり、化成処理皮膜の耐食性がより高まると考えられる。また、結合促進剤は、フッ素樹脂を軟質化してエマルションを構成する粒子同士をより密に融着しやすくすることにより、より紫外線などの光によって分解しにくい化成処理皮膜を形成する。そのため、結合促進剤を含む上記防錆処理液から形成された化成処理皮膜は、耐候性もより高まると考えられる。 1-3. Bonding accelerator The binding accelerator can soften the fluororesin existing in the rust preventive treatment liquid. The fluororesin softened by the bond accelerator forms a chemical conversion-treated film in which the particles constituting the emulsion are more likely to be fused more densely and water is less likely to permeate. Therefore, it is considered that the chemical conversion treatment film formed from the rust preventive treatment liquid containing the bond accelerator is less likely to generate red rust, and the corrosion resistance of the chemical conversion treatment film is further enhanced. Further, the bond accelerator softens the fluororesin to make it easier for the particles constituting the emulsion to be fused more closely, thereby forming a chemical conversion treatment film that is less likely to be decomposed by light such as ultraviolet rays. Therefore, it is considered that the chemical conversion treatment film formed from the rust preventive treatment liquid containing the bond accelerator has higher weather resistance.

また、上記結合促進剤は、上述した作用により、常温程度でもフッ素樹脂をよく融着させることができる。そのため、上記結合促進剤を含む防錆処理液は、鋼板またはめっき鋼板の溶接部などの基材鋼板の露出部位などに、加工現場で加熱せずにより容易に化成処理皮膜を形成することができる。 In addition, the above-mentioned bond accelerator can fuse the fluororesin well even at about room temperature due to the above-mentioned action. Therefore, the rust preventive treatment liquid containing the above-mentioned bond accelerator can easily form a chemical conversion treatment film on an exposed portion of a base steel plate such as a welded portion of a steel plate or a plated steel plate without heating at a processing site. ..

結合促進剤は、アジピン酸またはフタル酸と炭素数１以上３以下のアルコールとのエステル化合物およびｎ−メチル−２−ピロリドンから適宜選択して用いることができる。このような結合促進剤の例には、ジメチルアジペート、ジエチルアジペート、ジ（イソ）プロピルアジペート、ジ（イソ）ブチルアジペート、ジメチルフタレート、ジエチルフタレート、ジ（イソ）プロピルフタレート、ジ（イソ）ブチルフタレート、およびｎ−メチル−２−ピロリドンが含まれる。これらの結合促進剤のうち、耐食性、処理外観の観点からは、ジメチルアジペート、ジエチルアジペート、ジ（イソ）プロピルアジペートおよびジ（イソ）ブチルアジペートが好ましい。なお、本発明において、（イソ）プロピルとは、プロピルおよびイソプロピルを意味し、（イソ）ブチルとは、ブチルおよびイソブチルを意味する。 The bond promoter can be appropriately selected from an ester compound of adipic acid or phthalic acid and an alcohol having 1 to 3 carbon atoms and n-methyl-2-pyrrolidone. Examples of such bond promoters include dimethyl adipate, diethyl adipate, di (iso) propyl adipate, di (iso) butyl adipate, dimethyl phthalate, diethyl phthalate, di (iso) propyl phthalate, di (iso) butyl phthalate. , And n-methyl-2-pyrrolidone. Among these bond promoters, dimethyl adipate, diethyl adipate, di (iso) propyl adipate and di (iso) butyl adipate are preferable from the viewpoint of corrosion resistance and treated appearance. In the present invention, (iso) propyl means propyl and isopropyl, and (iso) butyl means butyl and isobutyl.

防錆処理液中の結合促進剤の含有量は、たとえば０．１ｇ／Ｌ以上１９．５ｇ／Ｌ以下とすることができるが、上述した作用によりフッ素樹脂をより融着しやすくして、化成処理皮膜の耐食性をより高める観点からは、０．５ｇ／Ｌ以上１９．５ｇ／Ｌ以下であることが好ましく、０．７ｇ／Ｌ以上１９．５ｇ／Ｌ以下であることがより好ましく、１ｇ／Ｌ以上１５ｇ／Ｌ以下であることがさらに好ましい。 The content of the bond accelerator in the rust preventive treatment liquid can be, for example, 0.1 g / L or more and 19.5 g / L or less. From the viewpoint of further enhancing the corrosion resistance of the treated film, it is preferably 0.5 g / L or more and 19.5 g / L or less, more preferably 0.7 g / L or more and 19.5 g / L or less, and 1 g / L. It is more preferably L or more and 15 g / L or less.

１−４．エッチング剤
エッチング剤は、基材鋼板の表面を均一化および活性化して、化成処理皮膜の密着性をより高め、化成処理皮膜から鋼板またはめっき鋼板への水の浸透を抑制する。そのため、結合促進剤を含む上記防錆処理液から形成された化成処理皮膜は赤錆を発生させにくくなり、化成処理皮膜の耐食性がより高まると考えられる。 1-4. Etching agent The etching agent homogenizes and activates the surface of the base steel sheet, further enhances the adhesion of the chemical conversion treatment film, and suppresses the permeation of water from the chemical conversion treatment film into the steel sheet or the plated steel sheet. Therefore, it is considered that the chemical conversion treatment film formed from the rust preventive treatment liquid containing the bond accelerator is less likely to generate red rust, and the corrosion resistance of the chemical conversion treatment film is further enhanced.

具体的には、エッチング剤は、めっき層に含まれるＺｎおよびＡｌおよび基材鋼板に含まれるＦｅなどの金属成分を溶解し、溶解した金属成分を化成処理皮膜中に取り込むことによって、化成処理皮膜が形成された鋼板またはめっき鋼板の耐食性を高める。このとき、本発明では、上記取り込まれた金属成分が、上述した結合促進剤によってエマルション状のフッ素樹脂のより内部にまで取り込まれて、化成処理皮膜の密着性もより高める結果、化成処理皮膜が形成された鋼板またはめっき鋼板の耐食性をより高めると考えられる。 Specifically, the etching agent dissolves metal components such as Zn and Al contained in the plating layer and Fe contained in the base steel sheet, and incorporates the dissolved metal components into the chemical conversion treatment film. Improves the corrosion resistance of the steel sheet or plated steel sheet on which is formed. At this time, in the present invention, the incorporated metal component is incorporated into the emulsion-like fluororesin by the above-mentioned bond accelerator, and the adhesion of the chemical conversion-treated film is further enhanced. As a result, the chemical conversion-treated film is formed. It is considered that the corrosion resistance of the formed steel sheet or plated steel sheet is further enhanced.

特に、エッチング剤は、基材鋼板の露出部位を活性化する観点からは、リン酸またはリン酸塩、およびアンモニアまたはアンモニウム塩が好ましい。 In particular, the etching agent is preferably phosphoric acid or phosphate, and ammonia or ammonium salt from the viewpoint of activating the exposed portion of the base steel plate.

リン酸またはリン酸塩は、基材鋼板の露出部位における鉄（Ｆｅ）や、Ｚｎ系めっきに含まれる亜鉛（Ｚｎ）を均一化および活性化する。そのため、リン酸またはリン酸塩は、鋼板およびＺｎ系めっき鋼板に特に有用である。 Phosphoric acid or phosphate homogenizes and activates iron (Fe) in the exposed portion of the base steel sheet and zinc (Zn) contained in Zn-based plating. Therefore, phosphoric acid or phosphate is particularly useful for steel sheets and Zn-based galvanized steel sheets.

リン酸またはリン酸塩は、リン酸アニオン（ＰＯ４ ３−）を有する水溶性の化合物であればよい。リン酸塩の例には、リン酸ナトリウム、リン酸アンモニウム、リン酸水素アンモニウム、リン酸二水素アンモニウム、リン酸マグネシウム、リン酸カリウム、リン酸マンガン、リン酸亜鉛、オルトリン酸、メタリン酸、ピロリン酸、三リン酸、および四リン酸などが含まれる。これらのリン酸またはリン酸塩は、単独で使用されてもよいし、２種類以上を組み合わせて使用されてもよい。 Phosphoric acid or a phosphate may be any water soluble compound having a phosphate anion (PO 4 3-). Examples of phosphates include sodium phosphate, ammonium phosphate, ammonium hydrogen phosphate, ammonium dihydrogen phosphate, magnesium phosphate, potassium phosphate, manganese phosphate, zinc phosphate, orthophosphoric acid, metaphosphoric acid, and pyrophosphoric acid. Includes acids, triphosphoric acid, and tetraphosphoric acid. These phosphoric acids or phosphates may be used alone or in combination of two or more.

アンモニア酸またはアンモニウム塩は、基材鋼板の露出部位における鉄（Ｆｅ）や、Ａｌ系めっきやＺｎ−Ａｌ系めっきに含まれるアルミニウム（Ａｌ）を均一化および活性化する。そのため、リン酸またはリン酸塩は、鋼板およびＺｎ−Ａｌ系めっき鋼板に特に有用である。 Ammonia acid or ammonium salt homogenizes and activates iron (Fe) in the exposed portion of the base steel sheet and aluminum (Al) contained in Al-based plating and Zn-Al-based plating. Therefore, phosphoric acid or phosphate is particularly useful for steel sheets and Zn—Al plated steel sheets.

アンモニウム塩の例には、第四級アンモニウムカチオン（ＮＨ４ ＋）のリン酸塩、フッ化物および金属塩などが含まれる。これらのうち、第四級アンモニウムカチオンのリン酸塩を含むことが好ましく、リン酸アンモニウム、リン酸水素アンモニウムおよびリン酸二水素アンモニウムを含むことがより好ましい。 Examples of ammonium salts, phosphates, quaternary ammonium cation (NH 4 +), and the like fluorides and metal salts. Of these, it is preferable to contain a quaternary ammonium cation phosphate, and more preferably to contain ammonium phosphate, ammonium hydrogen phosphate and ammonium dihydrogen phosphate.

なお、単一の防錆処理液で様々な鋼板やめっき鋼板（Ｚｎ系、Ａｌ系、Ｚｎ−Ａｌ系、およびＺｎ−Ａｌ−Ｍｇ系など）に適用可能にする観点からは、防錆処理液は、リン酸またはリン酸塩と、アンモニアまたはアンモニウム塩と、の双方を含むことが好ましい。また、基材鋼板の表面を均一化および活性化する効果をより高め、化成処理皮膜の耐候性をより高める観点からも、防錆処理液は、リン酸またはリン酸塩と、アンモニアまたはアンモニウム塩と、の双方を含むことが好ましい。これらの観点からは、エッチング剤は、第四級アンモニウムカチオンのリン酸塩が好ましく、リン酸アンモニウム、リン酸水素アンモニウムおよびリン酸二水素アンモニウムがより好ましい。 From the viewpoint of making it applicable to various steel sheets and plated steel sheets (Zn-based, Al-based, Zn-Al-based, Zn-Al-Mg-based, etc.) with a single rust-preventing liquid, the rust-preventing liquid Preferably contains both phosphoric acid or phosphate and ammonia or ammonium salt. Further, from the viewpoint of further enhancing the effect of homogenizing and activating the surface of the base steel plate and further enhancing the weather resistance of the chemical conversion treatment film, the rust preventive treatment liquid contains phosphoric acid or phosphate and ammonia or ammonium salt. And, it is preferable to include both. From these viewpoints, the etching agent is preferably a quaternary ammonium cation phosphate, more preferably ammonium phosphate, ammonium hydrogen phosphate and ammonium dihydrogen phosphate.

防錆処理液中のエッチング剤の含有量は、リン酸アニオン（ＰＯ４ ３−）の含有量が、リン酸アニオン換算で、１ｇ／Ｌ以上であることが好ましく、２ｇ／Ｌ以上であることがさらに好ましい。あるいは、防錆処理液中のエッチング剤の含有量は、第四級アンモニウムカチオン（ＮＨ４ ＋）の含有量が、第四級アンモニウムカチオン換算で、１ｇ／Ｌ以上であることが好ましく、２ｇ／Ｌ以上であることがさらに好ましい。 The content of the etchant rustproofing liquid is the content of phosphate anion (PO 4 3-) is a phosphate anion terms is preferably 1 g / L or more and 2 g / L or more Is even more preferable. Alternatively, regarding the content of the etching agent in the rust preventive treatment liquid, the content of the quaternary ammonium cation (NH 4 + ) is preferably 1 g / L or more in terms of the quaternary ammonium cation, and is 2 g / L. It is more preferably L or more.

防錆処理液中のエッチング剤の含有量は、エッチング剤がリン酸またはリン酸塩とアンモニアまたはアンモニウム塩との双方を含むときは、リン酸アニオン（ＰＯ４ ３−）および第四級アンモニウムカチオン（ＮＨ４ ＋）の含有量が、それぞれリン酸アニオン換算および第四級アンモニウムカチオン換算で、いずれも１ｇ／Ｌ以上であることが好ましく、２ｇ／Ｌ以上であることがさらに好ましい。 The content of the etchant rustproofing liquid, when the etching agent comprises both a phosphoric acid or phosphate salt with ammonia or an ammonium salt, phosphoric acid anion (PO 4 3-) and quaternary ammonium cations The content of (NH 4 + ) is preferably 1 g / L or more, and more preferably 2 g / L or more, in terms of anion phosphate and quaternary ammonium cation, respectively.

１−５．顔料
顔料は、化成処理鋼管の光沢および経時的な変色の抑制に寄与する。顔料は、一種でもそれ以上でもよい。顔料は、無機顔料および有機顔料のいずれでもよい。無機顔料の例には、カーボンブラック、シリカ、チタニアおよびアルミナが含まれる。有機顔料の例には、アクリルなどの樹脂粒子が含まれる。なお、「チタニア」は、４Ａ金属であるチタンを含むが、変色抑制効果に優れていることから、本明細書では顔料に分類される。 1-5. Pigments Pigments contribute to the suppression of gloss and discoloration of chemical conversion steel pipes over time. The pigment may be one kind or more. The pigment may be either an inorganic pigment or an organic pigment. Examples of inorganic pigments include carbon black, silica, titania and alumina. Examples of organic pigments include resin particles such as acrylic. Although "titania" contains titanium, which is a 4A metal, it is classified as a pigment in the present specification because it has an excellent discoloration suppressing effect.

１−６．ワックス
ワックスは、化成処理鋼管の加工性の向上に寄与する。所期の加工性を得る観点から、ワックスの融点は、８０〜１５０℃であることが好ましい。当該ワックスの例には、フッ素系ワックス、ポリエチレン系ワックスおよびスチレン系ワックスが含まれる。 1-6. Wax Wax contributes to the improvement of workability of chemical conversion treated steel pipes. From the viewpoint of obtaining the desired processability, the melting point of the wax is preferably 80 to 150 ° C. Examples of such waxes include fluorine-based waxes, polyethylene-based waxes and styrene-based waxes.

防錆処理液中のワックスの含有量は、０．５〜５質量％であることが、上記加工性の向上の観点から好ましい。当該含有量が０．５質量％以上であると、上記加工性の向上効果が十分に奏され、５質量％以下だと、パイリング時の荷崩れが生じにくい。化成処理皮膜中のワックスの含有量は、ガスクロマトグラフィーや高速液体クロマトグラフィー、質量分析法などの公知の定量分析法を利用して測定することが可能である。 The content of wax in the rust preventive treatment liquid is preferably 0.5 to 5% by mass from the viewpoint of improving the workability. When the content is 0.5% by mass or more, the effect of improving the workability is sufficiently exhibited, and when the content is 5% by mass or less, the load collapse during pileing is unlikely to occur. The wax content in the chemical conversion coating can be measured by using a known quantitative analysis method such as gas chromatography, high performance liquid chromatography, or mass spectrometry.

１−７．その他の成分
防錆処理液は、その他の成分として、上述以外の無機化合物、シランカップリング剤などの有機潤滑剤、無機潤滑剤、無機顔料、有機顔料、および染料などを必要に応じて添加してもよい。Ｍｇ、Ｃａ、Ｓｒ、Ｖ、Ｗ、Ｍｎ、Ｂ、Ｓｉ、Ｓｎなどの無機化合物（酸化物、リン酸塩など）は、化成処理皮膜を緻密化して耐水性を向上させる。フッ素系、ポリエチレン系、およびスチレン系などの有機潤滑剤、ならびに二硫化モリブデンおよびタルクなどの無機潤滑剤は、化成処理皮膜の潤滑性を向上させる。また、無機顔料、有機顔料、および染料などを配合することで、化成処理皮膜に所定の色調を付与することができる。 1-7. Other components In the rust preventive treatment liquid, as other components, inorganic compounds other than the above, organic lubricants such as silane coupling agents, inorganic lubricants, inorganic pigments, organic pigments, dyes, etc. are added as necessary. You may. Inorganic compounds (oxides, phosphates, etc.) such as Mg, Ca, Sr, V, W, Mn, B, Si, and Sn densify the chemical conversion coating to improve water resistance. Organic lubricants such as fluorine-based, polyethylene-based, and styrene-based, and inorganic lubricants such as molybdenum disulfide and talc improve the lubricity of the chemical conversion coating. Further, by blending an inorganic pigment, an organic pigment, a dye or the like, a predetermined color tone can be imparted to the chemical conversion treatment film.

なお、防錆処理液は、バナジウム（Ｖ）イオンおよびチタン（Ｔｉ）イオンの含有量が、金属換算で５００ｐｐｍ以下であることが好ましい。ＶやＴｉを含む化合物は、防錆剤として用いられることがあるが、これらのイオンの含有量をより少なくすることで、ＶやＴｉの光触媒作用による化成処理皮膜の耐候性の低下を抑制することができる。 The rust preventive treatment liquid preferably contains vanadium (V) ions and titanium (Ti) ions of 500 ppm or less in terms of metal. Compounds containing V and Ti are sometimes used as rust preventives, but by reducing the content of these ions, the decrease in weather resistance of the chemical conversion coating due to the photocatalytic action of V and Ti is suppressed. be able to.

また、防錆処理液は、クロム（Ｃｒ）、特には６価クロム、の含有量が、金属換算で１００ｐｐｍ以下であることが好ましい。Ｃｒ（６価クロム）の含有量をより少なくすることで、人体への影響が少なく、安全性の高い化成処理皮膜を形成することができる。 Further, the rust preventive treatment liquid preferably has a content of chromium (Cr), particularly hexavalent chromium, of 100 ppm or less in terms of metal. By reducing the content of Cr (hexavalent chromium), it is possible to form a highly safe chemical conversion treatment film with less influence on the human body.

また、防錆処理液は、クリアな皮膜を形成する観点から、無機顔料、有機顔料、および染料などを実質的に含まないことが好ましい。防錆処理液は、フッ素樹脂を主成分とするため、リン酸のマンガンまたは鉄などの塩によりリン酸塩皮膜を形成するリン酸塩処理（パーカライジング）や、多量の亜鉛粉末により犠牲防食層を形成するジンクリッチペイントとは異なり、クリアな皮膜を形成することができる。 Further, from the viewpoint of forming a clear film, the rust preventive treatment liquid preferably contains substantially no inorganic pigment, organic pigment, dye or the like. Since the rust preventive treatment liquid contains fluororesin as the main component, the sacrificial anticorrosion layer is formed by phosphate treatment (parking) that forms a phosphate film with a salt such as manganese or iron of phosphoric acid, and a large amount of zinc powder. Unlike the zinc rich paint that is formed, a clear film can be formed.

また、防錆処理液にシランカップリング剤を添加する場合、防錆処理液中のシランカップリング剤の含有量は、フッ素樹脂１００質量部に対して、０.５質量部以上５質量部以下であることが好ましい。シランカップリング剤の含有量が０.５質量部以上であると、化成処理皮膜の密着性をより高めることができる。一方、シランカップリング剤の含有量が５質量部以下であると、防錆処理液の保存安定性の低下を抑制できる。 When a silane coupling agent is added to the rust preventive treatment liquid, the content of the silane coupling agent in the rust preventive treatment liquid is 0.5 parts by mass or more and 5 parts by mass or less with respect to 100 parts by mass of the fluororesin. Is preferable. When the content of the silane coupling agent is 0.5 parts by mass or more, the adhesion of the chemical conversion treatment film can be further enhanced. On the other hand, when the content of the silane coupling agent is 5 parts by mass or less, the deterioration of the storage stability of the rust preventive treatment liquid can be suppressed.

１−８．防錆処理液の性状
防錆処理液は、水などの溶媒を除く固形分の含有量（固形分濃度）が、防錆処理液の全質量に対して２０質量％以上であることが好ましい。固形分の含有量が２０質量％以上であると、十分な膜厚を有し、十分な耐候性を有する化成処理皮膜を形成できる。なお、固形分の含有量の上限は処理液安定性の面から、４０質量％以下であることが好ましい。 1-8. Properties of the rust preventive treatment liquid The rust preventive treatment liquid preferably has a solid content (solid content concentration) excluding a solvent such as water of 20% by mass or more with respect to the total mass of the rust preventive treatment liquid. When the solid content is 20% by mass or more, a chemical conversion-treated film having a sufficient film thickness and sufficient weather resistance can be formed. The upper limit of the solid content is preferably 40% by mass or less from the viewpoint of the stability of the treatment liquid.

防錆処理液は、ｐＨが７．０以上９．５以下であることが好ましい。ｐＨが７．０以上であると、Ｚｎのエッチング量を適度に調整でき、ｐＨが９．５以下であると、Ａｌのエッチング量を適度に調整できる。そのため、ｐＨが７．０以上９．５以下であると、過剰なエッチングによる外観不良または耐食性の低下を抑制できる。 The rust preventive treatment liquid preferably has a pH of 7.0 or more and 9.5 or less. When the pH is 7.0 or more, the etching amount of Zn can be appropriately adjusted, and when the pH is 9.5 or less, the etching amount of Al can be appropriately adjusted. Therefore, when the pH is 7.0 or more and 9.5 or less, poor appearance or deterioration of corrosion resistance due to excessive etching can be suppressed.

防錆処理液は、１液型でもよいし、フッ素樹脂のエマルションと結合促進剤を含む溶液（または分散液）とを使用時に混合する２液混合型でもよい。 The rust preventive treatment liquid may be a one-component type or a two-component mixed type in which a fluororesin emulsion and a solution (or dispersion) containing a bond accelerator are mixed at the time of use.

２．溶接鋼管の化成処理方法
上述した防錆処理液は、溶接鋼管の化成処理に用いることができる。具体的には、上述した防錆処理液を、溶接鋼管の溶接部の表面またはめっきされた溶接鋼管の溶接部の表面に付与し、乾燥させて、化成処理皮膜を形成することができる。 2. Method for chemical conversion treatment of welded steel pipe The above-mentioned rust preventive treatment liquid can be used for chemical conversion treatment of welded steel pipe. Specifically, the above-mentioned rust preventive treatment liquid can be applied to the surface of the welded portion of the welded steel pipe or the surface of the welded portion of the plated welded steel pipe and dried to form a chemical conversion treatment film.

２−１．溶接鋼管
２−１−１．下地鋼
溶接鋼管の下地鋼の種類は、特に限定されない。たとえば、下地鋼は、低炭素鋼、中炭素鋼および高炭素鋼などを含む炭素鋼でもよいし、Ｍｎ、Ｃｒ、Ｓｉ、Ｎｉなどを含有する合金鋼でもよい。また、下地鋼は、Ａｌキルド鋼などを含むキルド鋼でもよいし、リムド鋼でもよい。良好なプレス成形性が必要とされる場合は、低炭素Ｔｉ添加鋼および低炭素Ｎｂ添加鋼などを含む深絞り用鋼板が下地鋼として好ましい。また、Ｐ、Ｓｉ、Ｍｎなどの量を特定の値に調整した高強度鋼板を下地鋼として用いてもよい。下地板の板厚は、特に限定されないが、０.８〜３.５ｍｍの範囲内が好ましい。 2-1. Welded steel pipe 2-1-1. Base steel The type of base steel for welded steel pipes is not particularly limited. For example, the base steel may be a carbon steel containing low carbon steel, medium carbon steel, high carbon steel, or the like, or an alloy steel containing Mn, Cr, Si, Ni, or the like. Further, the base steel may be a killed steel including Al killed steel or the like, or may be a rimmed steel. When good press formability is required, a steel plate for deep drawing containing low carbon Ti-added steel, low-carbon Nb-added steel, and the like is preferable as the base steel. Further, a high-strength steel plate in which the amounts of P, Si, Mn and the like are adjusted to specific values may be used as the base steel. The thickness of the base plate is not particularly limited, but is preferably in the range of 0.8 to 3.5 mm.

下地鋼は、上記鋼板を基材鋼板とし、公知のめっきを施したものであってもよい。めっきは、溶融めっきでも蒸着めっきでもよい。めっきの種類は、特に限定されず、Ｚｎ系めっき（Ｚｎめっき、Ｚｎ−Ａｌめっき、およびＺｎ−Ａｌ−Ｍｇめっきなど）、Ａｌ系めっき、ならびにＮｉ系めっきなどを使用することができる。これらのうち、Ｚｎ系めっきおよびＡｌ系めっきが好ましく、Ｚｎ系めっきがより好ましい。めっきの付着量は、特に限定されないが、９０〜１９０ｇ／ｍ２の範囲内が好ましい。 The base steel may be one in which the above-mentioned steel plate is used as a base steel plate and is plated with known material. The plating may be hot-dip plating or thin-film deposition plating. The type of plating is not particularly limited, and Zn-based plating (Zn plating, Zn-Al plating, Zn-Al-Mg plating, etc.), Al-based plating, Ni-based plating, and the like can be used. Of these, Zn-based plating and Al-based plating are preferable, and Zn-based plating is more preferable. The amount of plating adhered is not particularly limited, but is preferably in the range of 90 to 190 g / m 2.

本明細書において、「溶接鋼管の表面」というときは、下地鋼の最表面を意味し、たとえば、下地鋼の表面のうちめっきされていない領域については鋼板の表面を意味し、下地鋼の表面のうちめっきされた領域についてはめっき層の表面を意味する。また、後述する下地化成処理皮膜が形成されている領域については、「溶接鋼管の表面」は下地化成処理皮膜の表面を意味する。 In the present specification, the term "surface of welded steel pipe" means the outermost surface of the base steel, for example, the unplated region of the surface of the base steel means the surface of the steel plate, and the surface of the base steel. Of these, the plated region means the surface of the plating layer. Further, with respect to the region where the base chemical conversion treatment film described later is formed, the “surface of the welded steel pipe” means the surface of the base chemical conversion treatment film.

２−１−２．下地化成処理皮膜
下地鋼が溶接された溶接鋼管の、溶接部の表面には、耐食性および密着性を向上させる下地化成処理皮膜が形成されていてもよい。下地化成処理皮膜を形成することで、下地鋼またはめっきされた下地鋼の耐食性および密着性を向上させることができる。たとえば、下地鋼またはめっきされた下地鋼を製造してから造管するまでの間に輸送または保存しなければならない場合、下地鋼またはめっきされた下地鋼の表面に腐食が発生するおそれがある。このような場合、下地鋼またはめっきされた下地鋼の表面に予め下地化成処理皮膜を形成しておくと、下地鋼またはめっきされた下地鋼の表面における腐食の発生を防止することができる。 2-1-2. Base chemical conversion treatment film A base chemical conversion treatment film that improves corrosion resistance and adhesion may be formed on the surface of the welded portion of the welded steel pipe to which the base steel is welded. By forming the base chemical conversion treatment film, the corrosion resistance and adhesion of the base steel or the plated base steel can be improved. For example, if the base steel or plated base steel must be transported or stored between production and pipe making, corrosion may occur on the surface of the base steel or plated base steel. In such a case, if a base chemical conversion treatment film is formed in advance on the surface of the base steel or the plated base steel, it is possible to prevent the occurrence of corrosion on the surface of the base steel or the plated base steel.

耐候性の観点からは、下地化成処理皮膜は、ウレタン樹脂やエポキシ樹脂などをベースとする有機系皮膜よりも、無機系皮膜が好ましい。具体的には、無機系の下地化成処理皮膜としては、バルブメタルの酸化物または水酸化物と、バルブメタルのフッ化物とを含有するものが好ましい（特許文献１参照）。ここで「バルブメタル」とは、その酸化物が高い絶縁抵抗を示す金属をいう。バルブメタル元素としては、Ｔｉ、Ｚｒ、Ｈｆ、Ｖ、Ｎｂ、Ｔａ、ＭｏおよびＷから選ばれる１種または２種以上の元素が好ましい。 From the viewpoint of weather resistance, the base chemical conversion treatment film is preferably an inorganic film rather than an organic film based on a urethane resin, an epoxy resin, or the like. Specifically, as the inorganic base chemical conversion treatment film, one containing an oxide or hydroxide of a valve metal and a fluoride of the valve metal is preferable (see Patent Document 1). Here, the "valve metal" refers to a metal whose oxide exhibits high insulation resistance. As the valve metal element, one or more elements selected from Ti, Zr, Hf, V, Nb, Ta, Mo and W are preferable.

バルブメタルの酸化物または水酸化物を配合することで、環境負荷を小さくしつつ（クロムフリー）、優れた腐食抑制作用を付与することができる。下地化成処理皮膜にバルブメタルの酸化物または水酸化物を含ませるには、下地化成処理液にバルブメタル塩を添加すればよい。バルブメタル塩を含む下地化成処理液を乾燥させることで、バルブメタル塩がバルブメタルの酸化物または水酸化物になる。バルブメタル塩は、例えばバルブメタルのハロゲン化物や酸素酸塩などである。たとえば、チタン塩の例には、ＫｎＴｉＦ６（Ｋ：アルカリ金属またはアルカリ土類金属、ｎ：１または２）やＫ２［ＴｉＯ（ＣＯＯ）２］、（ＮＨ４）２ＴｉＦ６、ＴｉＣｌ４、ＴｉＯＳＯ４、Ｔｉ（ＳＯ４）２、Ｔｉ（ＯＨ）４などが含まれる。 By blending the oxide or hydroxide of the valve metal, it is possible to impart an excellent corrosion suppressing effect while reducing the environmental load (chrome-free). In order to include the oxide or hydroxide of the valve metal in the base chemical conversion treatment film, the valve metal salt may be added to the base chemical conversion treatment liquid. By drying the base chemical conversion treatment liquid containing the valve metal salt, the valve metal salt becomes an oxide or hydroxide of the valve metal. The valve metal salt is, for example, a halide of valve metal or an oxygen acid salt. For example, examples of titanium salts include K n TiF 6 (K: alkali metal or alkaline earth metal, n: 1 or 2), K 2 [TiO (COO) 2 ], (NH 4 ) 2 TiF 6 , TiCl. 4 , TIOSO 4 , Ti (SO 4 ) 2 , Ti (OH) 4, and the like are included.

また、バルブメタルのフッ化物を配合することで、優れた自己修復作用を付与することができる。バルブメタルのフッ化物は、雰囲気中の水分に溶け出した後、皮膜欠陥部において露出している基材（下地鋼またはめっきされた下地鋼）の表面に難溶性の酸化物または水酸化物となって再析出し、皮膜欠陥部を埋める。下地化成処理皮膜にバルブメタルの可溶性フッ化物を含ませるには、下地化成処理液にバルブメタルの可溶性フッ化物を添加してもよいし、バルブメタル塩と可溶性フッ化物（例えば（ＮＨ４）Ｆなど）とを組み合わせて添加してもよい。 Further, by blending the fluoride of the valve metal, an excellent self-healing action can be imparted. The fluoride of the valve metal dissolves in the moisture in the atmosphere, and then forms a poorly soluble oxide or hydroxide on the surface of the base material (base steel or plated base steel) exposed at the film defect portion. It re-precipitates and fills the defective part of the film. In order to include the soluble fluoride of valve metal in the base chemical conversion treatment film, the soluble fluoride of valve metal may be added to the base chemical conversion treatment liquid, or the valve metal salt and the soluble fluoride (for example, (NH 4 ) F) F. Etc.) may be added in combination with.

下地化成処理皮膜は、可溶性または難溶性の金属リン酸塩または複合リン酸塩を含んでいてもよい。可溶性のリン酸塩は、下地化成処理皮膜から皮膜欠陥部に溶出し、基材（下地鋼またはめっきされた下地鋼）のめっき成分（ＺｎやＡｌなど）と反応して不溶性リン酸塩となることで、バルブメタルの可溶性フッ化物による自己修復作用を補完する。また、難溶性のリン酸塩は、下地化成処理皮膜中に分散して皮膜強度を向上させる。可溶性の金属リン酸塩または複合リン酸塩に含まれる金属の例には、アルカリ金属、アルカリ土類金属、Ｍｎが含まれる。難溶性の金属リン酸塩または複合リン酸塩に含まれる金属の例には、Ａｌ、Ｔｉ、Ｚｒ、Ｈｆ、Ｚｎが含まれる。下地化成処理皮膜に可溶性または難溶性の金属リン酸塩または複合リン酸塩を含ませるには、下地化成処理液に各種金属リン酸塩を添加してもよいし、各種金属塩とリン酸、ポリリン酸またはリン酸塩とを組み合わせて添加してもよい。 The base chemical conversion coating may contain a soluble or sparingly soluble metal phosphate or composite phosphate. Soluble phosphate elutes from the base chemical conversion coating to the defective part of the film and reacts with the plating components (Zn, Al, etc.) of the base material (base steel or plated base steel) to become insoluble phosphate. This complements the self-healing action of the soluble fluoride of the valve metal. Further, the poorly soluble phosphate is dispersed in the base chemical conversion treatment film to improve the film strength. Examples of metals contained in soluble metal phosphates or composite phosphates include alkali metals, alkaline earth metals, and Mn. Examples of metals contained in sparingly soluble metal phosphates or composite phosphates include Al, Ti, Zr, Hf, Zn. In order to include a soluble or sparingly soluble metal phosphate or composite phosphate in the base chemical treatment film, various metal phosphates may be added to the base chemical treatment liquid, or various metal salts and phosphoric acid, It may be added in combination with polyphosphoric acid or phosphate.

また、下地化成処理皮膜は、フッ素系、ポリエチレン系、スチレン系などの有機ワックスや、シリカ、二硫化モリブデン、タルクなどの無機質潤滑剤などを含んでいてもよい。有機ワックスまたは無機質潤滑剤は、下地化成処理皮膜の潤滑性を向上させる。低融点の有機ワックスは、下地化成処理液を乾燥させるときに皮膜表面にブリードし、潤滑性を発現する。一方、高融点の有機ワックスおよび無機系潤滑剤は、下地化成処理皮膜の内部では分散して存在するが、最表層では島状に分布することによって潤滑性を発現する。 Further, the base chemical conversion treatment film may contain organic waxes such as fluorine-based, polyethylene-based and styrene-based, and inorganic lubricants such as silica, molybdenum disulfide and talc. Organic waxes or inorganic lubricants improve the lubricity of the base chemical conversion coating. The low melting point organic wax bleeds on the film surface when the base chemical conversion treatment liquid is dried, and exhibits lubricity. On the other hand, the high melting point organic wax and the inorganic lubricant are dispersed inside the base chemical conversion treatment film, but exhibit lubricity by being distributed in an island shape on the outermost layer.

下地化成処理皮膜の膜厚は、３〜１０００ｎｍの範囲内であることが好ましい。また、バルブメタルの付着量は、１ｍｇ／ｍ２以上であることが好ましい。下地化成処理皮膜の膜厚が３ｎｍ未満の場合、またはバルブメタルの付着量が１ｍｇ／ｍ２未満の場合、耐食性を十分に向上させることができないおそれがある。一方、下地化成処理皮膜の膜厚が１０００ｎｍを超える場合、下地鋼またはめっきされた下地鋼を成形加工する際にクラックが発生するおそれがある。 The film thickness of the base chemical conversion treatment film is preferably in the range of 3 to 1000 nm. The amount of the valve metal adhered is preferably 1 mg / m 2 or more. If the film thickness of the base chemical conversion treatment film is less than 3 nm, or if the amount of the valve metal adhered is less than 1 mg / m 2 , the corrosion resistance may not be sufficiently improved. On the other hand, if the film thickness of the base chemical conversion treatment film exceeds 1000 nm, cracks may occur when the base steel or the plated base steel is formed.

下地化成処理皮膜を蛍光Ｘ線やＥＳＣＡなどで元素分析すると、下地化成処理皮膜中のＯ濃度およびＦ濃度を測定することができる。これらの測定値から算出される元素濃度比Ｆ／Ｏ（原子比率）は、耐食性の観点から１／１００以上であることが好ましい。元素濃度比Ｆ／Ｏ（原子比率）が１／１００以上の場合、皮膜欠陥部を起点とする腐食の発生が顕著に抑制される。これは、十分な量のバルブメタルのフッ化物が下地化成処理皮膜中に含まれており、自己修復作用を発揮しているためと考えられる。 Elemental analysis of the base chemical conversion treatment film with fluorescent X-rays, ESCA, or the like can measure the O concentration and the F concentration in the base chemical conversion treatment film. The element concentration ratio F / O (atomic ratio) calculated from these measured values is preferably 1/100 or more from the viewpoint of corrosion resistance. When the element concentration ratio F / O (atomic ratio) is 1/100 or more, the occurrence of corrosion starting from the film defect portion is remarkably suppressed. It is considered that this is because a sufficient amount of fluoride of the valve metal is contained in the base chemical conversion treatment film and exerts a self-repairing action.

２−１−３．溶射補修層
めっきされた下地鋼板から製造された溶接鋼管（以下、単に「溶接めっき鋼管」ともいう。）の溶接部およびその近傍には、溶射補修層が形成されていることが好ましい。溶接めっき鋼管の製造工程では、多くの場合、溶接部から突出したビード突出部が切削され、溶接めっき鋼管の外周面が平滑化される（ビードカット）。ビードカットをする際には、ビード突出部だけでなく、その周囲のめっき層も除去されるため、下地鋼が露出してしまい、耐食性の低下の原因となる。そこで、溶接部およびその近傍の耐食性を回復させるため、下地鋼が露出した部位に溶射補修層を形成することが好ましい。 2-1-3. Thermal spray repair layer It is preferable that a thermal spray repair layer is formed at the welded portion of a welded steel pipe (hereinafter, also simply referred to as “welded plated steel pipe”) manufactured from a plated base steel plate and its vicinity. In the manufacturing process of a weld-plated steel pipe, in many cases, the bead protrusion protruding from the weld is cut to smooth the outer peripheral surface of the weld-plated steel pipe (bead cut). When the bead is cut, not only the protruding portion of the bead but also the plating layer around it is removed, so that the base steel is exposed, which causes a decrease in corrosion resistance. Therefore, in order to restore the corrosion resistance of the welded portion and its vicinity, it is preferable to form a thermal spray repair layer at the portion where the base steel is exposed.

図１は、本発明の一実施の形態に係る、Ａｌ含有Ｚｎ系合金めっき層が形成された溶接めっき鋼管１００の溶接部周辺の拡大断面図である。図１に示されるように、下地鋼板１１０の表面にＡｌ含有Ｚｎ系合金めっき層１２０が形成されたＡｌ含有Ｚｎ系合金めっき鋼板（原板）の表面には、バルブメタルの酸化物などを含む下地化成処理皮膜１３０が形成されている。この下地化成処理皮膜１３０が形成されたＡｌ含有Ｚｎ系合金めっき鋼板は、溶接金属１４０により溶接されている。溶接部およびその周辺は、ビードカットされており、溶接金属１４０だけでなく、Ａｌ含有Ｚｎ系合金めっき層１２０および下地化成処理皮膜１３０も除去されている。その結果、ビードカット部１５０では、下地鋼板１１０が露出している。溶射補修層１６０は、このビードカット部１５０に形成されており、下地鋼板１１０の露出している部分を被覆している。 FIG. 1 is an enlarged cross-sectional view of a welded portion of a welded plated steel pipe 100 on which an Al-containing Zn-based alloy plating layer is formed according to an embodiment of the present invention. As shown in FIG. 1, the surface of the Al-containing Zn-based alloy-plated steel sheet (original plate) in which the Al-containing Zn-based alloy plating layer 120 is formed on the surface of the base steel sheet 110 is a base containing an oxide of valve metal or the like. A chemical conversion treatment film 130 is formed. The Al-containing Zn-based alloy-plated steel sheet on which the base chemical conversion treatment film 130 is formed is welded with a weld metal 140. The welded portion and its surroundings are bead-cut, and not only the weld metal 140 but also the Al-containing Zn-based alloy plating layer 120 and the base chemical conversion treatment film 130 are removed. As a result, the base steel plate 110 is exposed in the bead cut portion 150. The thermal spray repair layer 160 is formed on the bead cut portion 150 and covers the exposed portion of the base steel plate 110.

図１に示されるように、本実施形態では、化成処理皮膜１７０は、溶射補修層１６０の表面のみならず、Ａｌ含有Ｚｎ系合金めっき鋼板の表面（より正確には、下地化成処理皮膜１３０の上）にも連続して形成されている。 As shown in FIG. 1, in the present embodiment, the chemical conversion coating 170 is not only the surface of the thermal spray repair layer 160, but also the surface of the Al-containing Zn-based alloy-plated steel sheet (more accurately, the base chemical conversion coating 130. It is also continuously formed in the above).

このように溶射補修層を形成する場合、溶射方法および溶射材の種類は特に限定されないが、溶射補修層の最表層にＡｌが０.０５原子％以上含まれるようにすることが好ましい。溶射補修層の表面にＡｌが含まれていると、溶射補修層から溶出したＡｌイオンと水性処理液に含まれる第４族元素のイオンとが反応することなどにより、化成処理皮膜の密着性などが向上するからである。たとえば、Ａｌ、ＺｎおよびＡｌの三連溶射とすることで、溶射補修層の最表層のＡｌ濃度を約１００原子％とすることができる。溶射補修層の最表層のＡｌ濃度は、ＸＰＳ装置による元素分析で測定することができる。 When the thermal spraying repair layer is formed in this way, the thermal spraying method and the type of the thermal spraying material are not particularly limited, but it is preferable that the outermost layer of the thermal spraying repair layer contains 0.05 atomic% or more of Al. When Al is contained on the surface of the thermal spray repair layer, the Al ions eluted from the thermal spray repair layer react with the ions of Group 4 elements contained in the aqueous treatment liquid, resulting in adhesion of the chemical conversion treatment film, etc. Is improved. For example, the Al concentration of the outermost layer of the thermal spray repair layer can be set to about 100 atomic% by performing triple thermal spraying of Al, Zn and Al. The Al concentration of the outermost layer of the thermal spray repair layer can be measured by elemental analysis using an XPS device.

溶射補修層の最表層のＡｌ濃度が０.０５原子％以上であれば、Ａｌ以外の溶射成分は特に限定されない。Ａｌ以外の溶射成分としては、ＭｇやＺｎなどが挙げられる。Ｍｇを含有させる場合（Ａｌ−Ｍｇ）、溶接めっき鋼管の加工性を確保する観点から、Ｍｇの含有量は５〜２０質量％の範囲内が好ましい。また、Ｚｎを含有させる場合（Ａｌ−Ｚｎ）、ピンホール部における犠牲防食効果を発揮させる観点および溶接めっき鋼管の加工性を確保する観点から、Ｚｎの含有量は０.０５〜３０質量％の範囲内が好ましい。 As long as the Al concentration of the outermost layer of the thermal spray repair layer is 0.05 atomic% or more, the thermal spray components other than Al are not particularly limited. Examples of the thermal spraying component other than Al include Mg and Zn. When Mg is contained (Al-Mg), the content of Mg is preferably in the range of 5 to 20% by mass from the viewpoint of ensuring the workability of the weld-plated steel pipe. When Zn is contained (Al-Zn), the Zn content is 0.05 to 30% by mass from the viewpoint of exerting a sacrificial anticorrosion effect in the pinhole portion and from the viewpoint of ensuring the workability of the welded plated steel pipe. Within the range is preferable.

溶射補修層の最表層のＡｌ濃度が０.０５原子％以上であれば、溶射方法は、単発溶射、二連溶射および三連溶射のいずれの方法でもよいが、Ａｌ−Ｚｎ−Ａｌの三連溶射が好ましい。Ａｌは溶接部の露出下地鋼やめっき層表面にある酸化皮膜に対する親和性が高いことから、一層目のＡｌは、溶接部に対する溶射補修層の密着性を向上させる。また、二層目のＺｎは、鉄に対する犠牲防食作用により下地鋼の腐食を抑制する効果を発揮する。さらに、三層目のＡｌは、白錆の発生も抑制して、溶射補修層のバリア機能をさらに向上させる。 As long as the Al concentration of the outermost layer of the thermal spray repair layer is 0.05 atomic% or more, the thermal spraying method may be any of single-shot spraying, double-spraying, and triple-spraying, but the Al-Zn-Al triplet. Thermal spraying is preferred. Since Al has a high affinity for the exposed base steel of the welded portion and the oxide film on the surface of the plating layer, Al of the first layer improves the adhesion of the thermal spray repair layer to the welded portion. Further, the Zn of the second layer exerts an effect of suppressing corrosion of the base steel by a sacrificial anticorrosion action against iron. Further, Al in the third layer also suppresses the generation of white rust and further improves the barrier function of the thermal spray repair layer.

溶射補修層の膜厚は、特に限定されないが、１０〜３０μｍの範囲内が好ましい。膜厚が１０μｍ未満の場合、溶接部の耐食性を十分に回復させることができないおそれがある。一方、膜厚が３０μｍ超の場合、製造コストの観点から好ましくないだけでなく、下地鋼に対する溶射補修層の密着性に悪影響が出るおそれがある。 The film thickness of the thermal spray repair layer is not particularly limited, but is preferably in the range of 10 to 30 μm. If the film thickness is less than 10 μm, the corrosion resistance of the welded portion may not be sufficiently restored. On the other hand, when the film thickness exceeds 30 μm, not only is it unfavorable from the viewpoint of manufacturing cost, but also the adhesion of the thermal spray repair layer to the base steel may be adversely affected.

２−２．化成処理皮膜の形成
上述した防錆処理液は、下地鋼、各種めっき層、下地化成処理皮膜および溶射補修層のいずれにも密着性が高い化成処理皮膜を形成できるため、溶接鋼管のうち、成形加工などにより基材鋼板が露出した部位、または溶射補修層が形成された部位に付与し、乾燥させて、化成処理皮膜を形成させることができる。具体的には、上記防錆処理液は、溶接鋼管の表面と、溶接部または溶接部を覆う溶射補修層と、の両方の上に付与される。さらには、上記防錆処理液は、溶接部の溶射補修層の表面のみならず、鋼板またはめっき鋼板の表面または下地化成処理皮膜の上と、その周囲の下地鋼、めっき層または下地化成処理皮膜と、の双方に接するように付与されることが好ましい。化成処理皮膜の形成を容易にし、かつ形成される化成処理皮膜の密着性をより高める観点からは、上述した防錆処理液は、溶接鋼管の溶接部を含む全周に付与されることが好ましい。 2-2. Formation of chemical conversion treatment film Since the above-mentioned rust prevention treatment liquid can form a chemical conversion treatment film having high adhesion to any of the base steel, various plating layers, the base chemical conversion treatment film and the spray repair layer, it is formed among the welded steel pipes. It can be applied to a portion where the base steel plate is exposed by processing or the like or a portion where a spray repair layer is formed and dried to form a chemical conversion treatment film. Specifically, the rust preventive treatment liquid is applied on both the surface of the welded steel pipe and the thermal spray repair layer covering the welded portion or the welded portion. Further, the rust preventive treatment liquid is applied not only to the surface of the thermal spray repair layer of the welded portion, but also to the surface of the steel plate or the plated steel plate or the base chemical conversion treatment film and the base steel, the plating layer or the base chemical conversion treatment film around the surface. And, it is preferable that it is given so as to be in contact with both. From the viewpoint of facilitating the formation of the chemical conversion treatment film and further enhancing the adhesion of the formed chemical conversion treatment film, it is preferable that the above-mentioned rust preventive treatment liquid is applied to the entire circumference including the welded portion of the welded steel pipe. ..

上記成形加工の例には、絞り加工、曲げ加工、ロールフォーミング加工、せん断加工、溶接加工、および溶射加工などが含まれる。 Examples of the molding process include drawing process, bending process, roll forming process, shearing process, welding process, thermal spraying process and the like.

たとえば、溶接鋼管を製造する場合は、めっき鋼板をロールフォーミング加工によりオープンパイプ状に成形した後、めっき鋼板の幅方向の端部を溶接する。次いで、溶接鋼管から突出したビード突出部を切削した後、ビードカットされた溶接部に溶射補修層を形成すればよい。 For example, in the case of manufacturing a welded steel pipe, the plated steel sheet is formed into an open pipe by roll forming, and then the end portion of the plated steel sheet in the width direction is welded. Next, after cutting the bead protruding portion protruding from the welded steel pipe, a thermal spray repair layer may be formed on the bead-cut welded portion.

めっき層を溶かして溶接加工した溶接部では、比較的広い範囲で基材鋼板が露出して、めっき層による犠牲防食作用が低下して耐食性が低下しやすい。しかし、このような溶接部に上述した防錆処理液を付与、乾燥させて化成処理皮膜を形成すると、耐食性が顕著に向上する。 In the welded portion where the plating layer is melted and welded, the base steel plate is exposed in a relatively wide range, the sacrificial anticorrosion action of the plating layer is lowered, and the corrosion resistance is likely to be lowered. However, when the above-mentioned rust preventive treatment liquid is applied to such a welded portion and dried to form a chemical conversion treatment film, the corrosion resistance is remarkably improved.

防錆処理液の塗布方法は、特に限定されず、溶接鋼管の形状などに応じて適宜選択すればよい。塗布方法の例には、ロールコート法、カーテンフロー法、スピンコート法、スプレー法、浸漬引き上げ法、および滴下法などが含まれる。防錆処理液の液膜の厚さは、フェルト絞りやエアワイパーなどにより調整することができる。 The method of applying the rust preventive treatment liquid is not particularly limited, and may be appropriately selected depending on the shape of the welded steel pipe and the like. Examples of coating methods include a roll coating method, a curtain flow method, a spin coating method, a spray method, a dipping pulling method, a dropping method and the like. The thickness of the liquid film of the rust preventive treatment liquid can be adjusted with a felt squeezer, an air wiper, or the like.

防錆処理液の塗布量は、特に限定されないが、化成処理皮膜の膜厚が０.５μｍ以上１０μｍ以下となるように調整されることが好ましい。化成処理皮膜の膜厚が０.５μｍ以上であると、化成処理皮膜に耐候性、耐食性および耐変色性などを十分に付与することができる。一方、膜厚を１０μｍ超としても、膜厚の増加に伴う性能向上を期待することはできない。 The amount of the rust preventive treatment liquid applied is not particularly limited, but it is preferable that the film thickness of the chemical conversion treatment coating is adjusted to be 0.5 μm or more and 10 μm or less. When the film thickness of the chemical conversion-treated film is 0.5 μm or more, weather resistance, corrosion resistance, discoloration resistance, and the like can be sufficiently imparted to the chemical conversion-treated film. On the other hand, even if the film thickness exceeds 10 μm, it cannot be expected that the performance will be improved as the film thickness increases.

付与された防錆処理液は、常温で乾燥させて、化成処理皮膜とすることができる。なお、付与された防錆処理液を加熱（たとえば５０℃以上に加熱）して乾燥させてもよいが、このとき、有機成分の熱分解による化成処理皮膜の性能低下を抑制する観点からは、乾燥温度は３００℃以下であることが好ましい。なお、加工現場などにおいて、より容易に化成処理皮膜を形成する観点からは、常温で乾燥させることが好ましい。 The applied rust preventive treatment liquid can be dried at room temperature to form a chemical conversion treatment film. The applied rust preventive treatment liquid may be heated (for example, heated to 50 ° C. or higher) to be dried, but at this time, from the viewpoint of suppressing deterioration of the performance of the chemical conversion treatment film due to thermal decomposition of the organic component, it is possible to dry it. The drying temperature is preferably 300 ° C. or lower. From the viewpoint of more easily forming a chemical conversion treatment film at a processing site or the like, it is preferable to dry at room temperature.

３．溶接鋼管および溶接鋼管の成形加工品
上述の防錆処理液から形成された化成処理皮膜を有する溶接鋼管は、溶接鋼管と、上記溶接鋼管の表面に形成された上記化成処理皮膜と、を有する。上記溶接鋼管は、成形加工品であってもよい。成形加工の方法は特に限定されず、公知の方法から選択することができる。上記化成処理皮膜は、溶接鋼管の溶接部に形成される。上記化成処理皮膜は、溶接鋼管の表面と、溶接部または溶接部を覆う溶射補修層と、の両方の上に形成されることが好ましい。さらには、上記化成処理皮膜は、溶接部の溶射補修層の表面のみならず、鋼板またはめっき鋼板の表面または下地化成処理皮膜の上と、その周囲の下地鋼、めっき層または下地化成処理皮膜と、の双方に接するように形成されることが好ましい。化成処理皮膜の形成を容易にし、かつ形成される化成処理皮膜の密着性をより高める観点からは、上記化成処理皮膜は、溶接鋼管の溶接部を含む全周に形成されることが好ましい。 3. 3. Welded steel pipe and molded product of welded steel pipe A welded steel pipe having a chemical conversion treatment film formed from the above-mentioned rust preventive treatment liquid has a welded steel pipe and the above-mentioned chemical conversion treatment film formed on the surface of the welded steel pipe. The welded steel pipe may be a molded product. The molding process is not particularly limited and can be selected from known methods. The chemical conversion treatment film is formed on the welded portion of the welded steel pipe. The chemical conversion treatment film is preferably formed on both the surface of the welded steel pipe and the welded portion or the thermal spray repair layer covering the welded portion. Further, the chemical conversion treatment film is not only on the surface of the spray repair layer of the welded portion, but also on the surface of the steel plate or the plated steel sheet or the base chemical conversion treatment film, and the base steel, the plating layer or the base chemical conversion treatment film around the steel plate or the base chemical conversion treatment film. , Are preferably formed so as to be in contact with both of them. From the viewpoint of facilitating the formation of the chemical conversion treatment film and further enhancing the adhesion of the formed chemical conversion treatment film, it is preferable that the chemical conversion treatment film is formed on the entire circumference including the welded portion of the welded steel pipe.

より具体的には、上記化成処理皮膜は、上述のフッ素樹脂を含む有機樹脂と、上述の第４族元素を含む化合物または第４族元素のイオンと、アジピン酸またはフタル酸と炭素数１以上３以下のアルコールとのエステル化合物およびｎ−メチル−２−ピロリドンからなる群から選択される１以上の結合促進剤と、を含む。 More specifically, the chemical conversion coating comprises the above-mentioned organic resin containing a fluororesin, the above-mentioned compound containing a Group 4 element or an ion of a Group 4 element, adipic acid or phthalic acid, and 1 or more carbon atoms. Includes 3 or less ester compounds with alcohol and one or more binding promoters selected from the group consisting of n-methyl-2-pyrrolidone.

これらの成分の含有量比は、防錆処理液について上述した比率と同様である。 The content ratio of these components is the same as the ratio described above for the rust preventive treatment liquid.

化成処理皮膜の膜厚は、０.５μｍ以上１０μｍ以下であることが好ましい。膜厚が０.５μｍ以上であると、化成処理皮膜に耐候性、耐食性および耐変色性などを十分に付与することができる。一方、膜厚を１０μｍ超としても、膜厚の増加に伴う性能向上を期待することはできない。 The film thickness of the chemical conversion treatment film is preferably 0.5 μm or more and 10 μm or less. When the film thickness is 0.5 μm or more, weather resistance, corrosion resistance, discoloration resistance, and the like can be sufficiently imparted to the chemical conversion-treated film. On the other hand, even if the film thickness exceeds 10 μm, it cannot be expected that the performance will be improved as the film thickness increases.

この溶接鋼管は、耐候性、特には長期の耐候性に優れるほか、溶接部の耐食性が高まる。 This welded steel pipe is excellent in weather resistance, particularly long-term weather resistance, and also enhances the corrosion resistance of the welded portion.

以下、実施例を参照して本発明を詳細に説明するが、本発明はこれらの実施例により限定されない。 Hereinafter, the present invention will be described in detail with reference to Examples, but the present invention is not limited to these Examples.

１．防錆処理液の調製
各成分を混合して、表１に示す防錆処理液１〜防錆処理液２０を調製した。 1. 1. Preparation of rust preventive treatment liquid Each component was mixed to prepare rust preventive treatment liquid 1 to rust preventive treatment liquid 20 shown in Table 1.

なお、フッ素樹脂（ＦＲ）は、フッ素系樹脂（Ｔｇ：−３５〜２５℃、最低成膜温度（ＭＦＴ）：１０℃）の水系エマルションを使用した。上記フッ素樹脂エマルションの固形分濃度は３８質量％であり、フッ素樹脂中のフッ素原子の含有量は２５質量％であり、エマルションの平均粒径は１５０ｎｍであった。 As the fluororesin (FR), an aqueous emulsion of a fluororesin (Tg: 35 to 25 ° C., minimum film formation temperature (MFT): 10 ° C.) was used. The solid content concentration of the fluororesin emulsion was 38% by mass, the content of fluorine atoms in the fluororesin was 25% by mass, and the average particle size of the emulsion was 150 nm.

アクリル樹脂（ＡＲ）は、アクリル樹脂エマルションである、ＤＩＣ株式会社製の「パテラコール」（「パテラコール」は同社の登録商標）を用意した。「パテラコール」の固形分濃度は４０質量％であり、エマルションの平均粒径は１０〜１００ｎｍ程度と思われた。 As the acrylic resin (AR), "Patellacol" manufactured by DIC Corporation ("Patellacol" is a registered trademark of the company), which is an acrylic resin emulsion, was prepared. The solid content concentration of "Patellacol" was 40% by mass, and the average particle size of the emulsion was considered to be about 10 to 100 nm.

ウレタン樹脂（ＰＵ）は、ウレタン樹脂エマルションである、ＤＩＣ株式会社製の「ハイドラン」を使用した。「ハイドラン」の固形分濃度は３５質量％であり、エマルションの平均粒径は１０〜１００ｎｍ程度と思われた。 As the urethane resin (PU), "Hydran" manufactured by DIC Corporation, which is a urethane resin emulsion, was used. The solid content concentration of "Hydran" was 35% by mass, and the average particle size of the emulsion was considered to be about 10 to 100 nm.

エッチング剤については、リン酸量は、リン酸、リン酸水素二アンモニウムおよびリン酸二水素アンモニウムの合計量で調整し、アンモニウム量は、アンモニア（水溶液）、炭酸ジルコニウムアンモニウム、フッ化ジルコニウムアンモニウム、リン酸水素二アンモニウム、リン酸二水素アンモニウムおよび炭酸アンモニウムの合計量で調整した。 For the etching agent, the amount of phosphoric acid is adjusted by the total amount of phosphoric acid, diammonium hydrogen phosphate and ammonium dihydrogen phosphate, and the amount of ammonium is ammonia (aqueous solution), ammonium zirconium carbonate, ammonium dihydrogen fluoride, phosphorus. The total amount of diammonium hydrogen acid, ammonium dihydrogen phosphate and ammonium carbonate was adjusted.

なお、表１の「Ｆ量」、「Ｚｒ量」、「添加量」、「リン酸量」および「アンモニウム量」は、それぞれ、フッ素原子の量（質量％）、第４族元素を含む化合物の金属換算での量（ｇ／Ｌ）、結合促進剤の添加量（ｇ／Ｌ）、リン酸またはリン酸塩のリン酸アニオン換算での含有量（ｇ／Ｌ）、およびアンモニアまたはアンモニウム塩の第四級アンモニウムカチオン換算での含有量（ｇ／Ｌ）を示す。 The "F amount", "Zr amount", "addition amount", "phosphoric acid amount" and "ammonium amount" in Table 1 are compounds containing a fluorine atom amount (mass%) and a Group 4 element, respectively. Metal equivalent (g / L), bond promoter addition amount (g / L), phosphate or phosphate anion equivalent content (g / L), and ammonia or ammonium salts The content (g / L) in terms of quaternary ammonium cation is shown.

また、表１の「有機樹脂」の「種類」に「ＦＲ／ＡＲ」と記載されているときは、上記フッ素樹脂と上記アクリル樹脂とをブレンドして、他の化合物とあわせた防錆処理液中の固形分量が「固形分量」に記載の数値になり、かつ、フッ素原子の量が「Ｆ量」に記載の数値になるように調整したことを示す。 When "FR / AR" is described in "Type" of "Organic resin" in Table 1, a rust preventive treatment liquid obtained by blending the above fluororesin and the above acrylic resin and combining them with other compounds. It is shown that the amount of solid content in the medium is adjusted to be the value described in "Amount of solid content" and the amount of fluorine atoms is adjusted to be the value described in "Amount of F".

Figure 0006962216
Figure 0006962216

２．溶接鋼管の形成
板厚１.２ｍｍの鋼板の表面に、表２に示すめっきを施して、めっき材Ａおよびめっき材Ｂとした。めっき材Ａおよびめっき材Ｂの表面に、表３に示す組成の下地水性処理液を塗布し、到達板温１４０℃で加熱乾燥して下地化成処理皮膜を形成した。形成された下地化成処理皮膜中のバルブメタルの付着量および下地化成処理皮膜の組成を表４に示す。 2. Formation of Welded Steel Pipe The surface of a steel plate having a plate thickness of 1.2 mm was plated as shown in Table 2 to obtain plating material A and plating material B. A base water-based treatment liquid having the composition shown in Table 3 was applied to the surfaces of the plating material A and the plating material B, and heat-dried at a reaching plate temperature of 140 ° C. to form a base chemical conversion treatment film. Table 4 shows the amount of valve metal adhered to the formed base chemical conversion treatment film and the composition of the base chemical conversion treatment film.

Figure 0006962216
Figure 0006962216

Figure 0006962216
Figure 0006962216

Figure 0006962216
Figure 0006962216

下地化成処理皮膜を形成しためっき鋼板をオープンパイプ状に成形した後、幅方向の両端部を高周波溶接して直径２５.４ｍｍの溶接めっき鋼管を作製した。次いで、溶接部をビードカットした後、表５に示す溶射条件で幅１０ｍｍの溶射補修層を形成した。 After forming a plated steel sheet on which a base chemical conversion treatment film was formed into an open pipe shape, both ends in the width direction were high-frequency welded to prepare a welded plated steel pipe having a diameter of 25.4 mm. Next, after bead-cutting the welded portion, a thermal spray repair layer having a width of 10 mm was formed under the thermal spraying conditions shown in Table 5.

Figure 0006962216
Figure 0006962216

作製した溶接めっき鋼管を温水で洗浄した後、表１に示す水性処理液１〜水性処理液２０のいずれかを溶接めっき鋼管の表面に滴下により塗布し、スポンジで扱いた後、ドライヤを用いて到達板温５５℃で加熱乾燥して、化成処理皮膜を形成した。 After washing the prepared weld-plated steel pipe with warm water, any of the water-based treatment liquid 1 to the water-based treatment liquid 20 shown in Table 1 is drip-applied to the surface of the weld-plated steel pipe, treated with a sponge, and then used with a dryer. A chemical conversion-treated film was formed by heating and drying at a plate temperature of 55 ° C.

３．評価
防錆処理液１〜防錆処理液２０から形成した皮膜の耐候性および溶射部耐食性を、以下の基準で評価した。 3. 3. Evaluation The weather resistance and the corrosion resistance of the sprayed portion of the film formed from the rust preventive treatment liquid 1 to the rust preventive treatment liquid 20 were evaluated according to the following criteria.

３−１．耐候性
ＪＩＳ Ｋ ５６００−７−７：２００８に準拠して促進耐候性試験（キセノンランプ法）を実施した。本試験法では、キセノンアーク灯の光を１２０分間照射する間に１８分間水を噴霧する工程を１サイクル（２時間）として２００ｃｙｃ試験行った。試験前後における化成処理皮膜の厚さ比（ＴＲ）に応じて、以下の基準にて皮膜の耐候性を評価した。
Ａ 化成処理皮膜の厚さ比ＴＲは８０％以上だった
Ｂ 化成処理皮膜の厚さ比ＴＲは６０％以上８０％未満だった
Ｃ 化成処理皮膜の厚さ比ＴＲは４０％以上６０％未満だった
Ｄ 化成処理皮膜の厚さ比ＴＲは２０％以上４０％未満だった
Ｅ 化成処理皮膜の厚さ比ＴＲは２０％未満だった 3-1. Weather resistance An accelerated weather resistance test (xenon lamp method) was carried out in accordance with JIS K 5600-7-7: 2008. In this test method, a 200 cyc test was carried out with one cycle (2 hours) of spraying water for 18 minutes while irradiating with light from a xenon arc lamp for 120 minutes. The weather resistance of the chemical conversion coating was evaluated according to the following criteria according to the thickness ratio (TR) of the chemical conversion coating before and after the test.
A The thickness ratio TR of the chemical conversion treatment film was 80% or more. B The thickness ratio TR of the chemical conversion treatment film was 60% or more and less than 80%. C The thickness ratio TR of the chemical conversion treatment film was 40% or more and less than 60%. D The thickness ratio TR of the chemical conversion treatment film was 20% or more and less than 40%. E The thickness ratio TR of the chemical conversion treatment film was less than 20%.

３−２．溶射部耐食性
試験片の端面をシールし、上記対候性の評価と同様の手順による促進耐候性試験を２００ｃｙｃ試験行った。その後、３５℃の環境下で５％ＮａＣｌ含有塩水を２時間噴射し、６０℃かつ相対湿度３０％の環境下で４時間かけて強制乾燥させ、その後、５０℃かつ相対湿度９５％の環境下で２時間湿潤処理を行う工程を１サイクル（８時間）とする複合サイクル腐食試験を３００ｃｙｃ行った。試験後に溶射部に発生した赤錆発生面積率（ＷＲ）に応じて、以下の基準にて皮膜の溶射部耐食性を評価した。
Ａ 赤錆発生面積率（ＷＲ）は１０％以下だった
Ｂ 赤錆発生面積率（ＷＲ）は１０％超２０％以下だった
Ｃ 赤錆発生面積率（ＷＲ）は２０％超５０％以下だった
Ｄ 赤錆発生面積率（ＷＲ）は５０超８０％以下だった
Ｅ 赤錆発生面積率（ＷＲ）は８０％超だった 3-2. The end face of the thermal sprayed portion corrosion resistance test piece was sealed, and an accelerated weather resistance test was carried out in a 200 cyc test by the same procedure as the above weather resistance evaluation. Then, 5% NaCl-containing salt water is sprayed in an environment of 35 ° C. for 2 hours, forcibly dried in an environment of 60 ° C. and a relative humidity of 30% for 4 hours, and then in an environment of 50 ° C. and a relative humidity of 95%. A combined cycle corrosion test was carried out in which the step of performing the wet treatment for 2 hours was one cycle (8 hours). The corrosion resistance of the sprayed portion of the film was evaluated according to the following criteria according to the red rust generation area ratio (WR) generated in the sprayed portion after the test.
A Red rust occurrence area ratio (WR) was 10% or less B Red rust occurrence area ratio (WR) was more than 10% and 20% or less C Red rust occurrence area ratio (WR) was more than 20% and 50% or less D Red rust Area ratio (WR) was more than 50 and 80% or less E Red rust area ratio (WR) was more than 80%

３−３．処理液安定性
各防錆処理液を密閉容器内で常温で１８０日間保管した。フォードカップ＃４からの流下時間を保管前後で比較し、増粘を評価した。
Ａ 保管後の流下時間の増加は４秒未満だった
Ｂ 保管後の流下時間の増加は４秒以上だった 3-3. Treatment liquid stability Each rust preventive treatment liquid was stored in a closed container at room temperature for 180 days. The flow time from Ford Cup # 4 was compared before and after storage to evaluate the thickening.
A The increase in flow time after storage was less than 4 seconds B The increase in flow time after storage was more than 4 seconds

各化成処理溶接めっき鋼管についての、使用した基材の種類、処理液の種類、乾燥温度、および形成された皮膜の膜厚、ならびに耐候性および溶射条件ごとの溶射部耐食性の評価結果を表６および表７に示す。 Table 6 shows the evaluation results of the type of base material used, the type of treatment liquid, the drying temperature, the film thickness of the formed film, and the weather resistance and the corrosion resistance of the sprayed part for each spraying condition for each chemical conversion welded plated steel pipe. And shown in Table 7.

Figure 0006962216
Figure 0006962216

Figure 0006962216
Figure 0006962216

フッ素樹脂を含む有機樹脂と、第４族元素を含む化合物または第４族元素のイオンと、結合促進剤と、を含む防錆処理液１〜防錆処理液１５を用いて化成処理皮膜を形成すると、化成処理皮膜の密着性、耐候性および耐食性がいずれも良好であった。 A chemical conversion treatment film is formed using an organic resin containing a fluororesin, a compound containing a Group 4 element or an ion of a Group 4 element, and a rust preventive treatment liquid 1 to a rust preventive treatment liquid 15 containing a bond accelerator. Then, the adhesion, weather resistance, and corrosion resistance of the chemical conversion coating were all good.

特に、フッ素樹脂の全質量に対して８質量％以上のフッ素（Ｆ）原子を含む防錆処理液３〜防錆処理液１５を用いて化成処理皮膜を形成すると、耐候性がより高くなり、耐食性がより高くなる傾向が見られた。 In particular, when a chemical conversion treatment film is formed using the rust preventive treatment liquid 3 to the rust preventive treatment liquid 15 containing 8% by mass or more of fluorine (F) atoms with respect to the total mass of the fluororesin, the weather resistance becomes higher. There was a tendency for higher corrosion resistance.

また、エッチング剤を含む防錆処理液６〜防錆処理液１５を用いて化成処理皮膜を形成すると、耐食性がより高くなる傾向が見られ、エッチング剤として、リン酸またはリン酸塩と、アンモニアまたはアンモニウム塩と、をいずれも含む防錆処理液９〜防錆処理液１５を用いて化成処理皮膜を形成すると、耐食性がさらに高くなった。 Further, when a chemical conversion film is formed by using the rust preventive treatment liquid 6 to the rust preventive treatment liquid 15 containing an etching agent, the corrosion resistance tends to be higher, and as the etching agent, phosphoric acid or phosphate and ammonia are observed. Alternatively, when the chemical conversion treatment film was formed by using the rust preventive treatment liquid 9 to the rust preventive treatment liquid 15 containing both ammonium salts, the corrosion resistance was further improved.

一方で、フッ素樹脂以外の樹脂を含む防錆処理液１６〜防錆処理液１８を用いて化成処理皮膜を形成すると、耐候性および耐食性が低かった。 On the other hand, when the chemical conversion treatment film was formed by using the rust preventive treatment liquid 16 to the rust preventive treatment liquid 18 containing a resin other than the fluororesin, the weather resistance and the corrosion resistance were low.

また、第４族元素を含む化合物または第４族元素のイオンを含まない防錆処理液１９を用いて化成処理皮膜を形成すると、密着性が低かった。 Further, when the chemical conversion treatment film was formed by using the compound containing the Group 4 element or the rust preventive treatment liquid 19 not containing the ion of the Group 4 element, the adhesion was low.

また、結合促進剤を含まない防錆処理液２０を用いて化成処理皮膜を形成すると、耐食性が低かった。 Further, when the chemical conversion treatment film was formed by using the rust preventive treatment liquid 20 containing no bond accelerator, the corrosion resistance was low.

本発明の防錆処理液により製造される化成処理皮膜は、溶接鋼管の耐食性、特には溶接鋼管の溶接部における耐食性をより高めることができる。たとえば、本発明の防錆処理液は、１）ビニールハウスまたは農業ハウス用の鋼管、形鋼、支柱、梁、搬送用部材、２）遮音壁、防音壁、吸音壁、防雪壁、ガードレール、高欄、防護柵、支柱、３）鉄道車両用部材、架線用部材、電気設備用部材、安全環境用部材、構造用部材、太陽光架台などの用途に使用する鋼板またはめっき鋼板へのポストコートによる化成処理皮膜の形成に好適に使用されうる。 The chemical conversion treatment film produced by the rust preventive treatment liquid of the present invention can further enhance the corrosion resistance of the welded steel pipe, particularly the corrosion resistance at the welded portion of the welded steel pipe. For example, the rust-preventive treatment liquid of the present invention includes 1) steel pipes, shaped steel, columns, beams, transport members, 2) sound-insulating walls, sound-proof walls, sound-absorbing walls, snow-proof walls, guardrails, balustrades, etc. Chemical treatment by post-coating on steel sheets or plated steel sheets used for applications such as protective fences, columns, 3) railroad vehicle members, overhead wire members, electrical equipment members, safety environment members, structural members, solar mounts, etc. It can be suitably used for forming a film.

１００ 溶接めっき鋼管
１１０ 下地鋼板
１２０ Ａｌ含有Ｚｎ系合金めっき層
１３０ 地化成処理皮膜
１４０ 溶接金属
１５０ ビードカット部
１６０ 溶射補修層
１７０ 化成処理皮膜 100 Welded plated steel pipe 110 Base steel plate 120 Al-containing Zn-based alloy plating layer 130 Geochemical conversion treatment film 140 Welded metal 150 Bead cut part 160 Thermal spray repair layer 170 Chemical conversion treatment film

Claims (16)

フッ素樹脂およびアクリル樹脂を含む有機樹脂と、
ジルコニウム化合物と、
ジエチルアジペート、ジブチルアジペート、ジメチルアジペートおよびｎ−メチル−２−ピロリドンからなる群から選択される１以上の結合促進剤を、を含み、
前記ジルコニウム化合物の含有量は、金属換算で０．５ｇ／Ｌ以上６ｇ／Ｌ以下であり、
前記ジルコニウム化合物の金属換算した含有量と前記結合促進剤の含有量の合計は、２０ｇ／Ｌ以下である、
溶接鋼管用防錆処理液。 Organic resins including fluororesins and acrylic resins,
With zirconium compounds
Containing one or more binding promoters selected from the group consisting of diethyl adipate, dibutyl adipate, dimethyl adipate and n-methyl-2-pyrrolidone.
The content of the zirconium compound is 0.5 g / L or more and 6 g / L or less in terms of metal.
The total of the metal-equivalent content of the zirconium compound and the content of the bond promoter is 20 g / L or less.
Rust preventive treatment liquid for welded steel pipes. 前記アクリル樹脂は、前記アクリル樹脂の全質量に対して６質量％以上のフッ素原子を含む、請求項１に記載の溶接鋼管用防錆処理液。 The acrylic resin comprises 6% by weight or more of fluorine atoms based on the total weight of the acrylic resin, welded steel pipe for rust prevention treatment solution according to claim 1. 前記ジルコニウム化合物の含有量は、金属換算で２ｇ／Ｌ以上である、請求項１または２に記載の溶接鋼管用防錆処理液。 The rust preventive treatment liquid for welded steel pipes according to claim 1 or 2, wherein the content of the zirconium compound is 2 g / L or more in terms of metal. 前記結合促進剤の含有量は０．５ｇ／Ｌ以上５０ｇ／Ｌ以下である、請求項１〜３のいずれか１項に記載の溶接鋼管用防錆処理液。 The rust preventive treatment liquid for welded steel pipes according to any one of claims 1 to 3, wherein the content of the bond accelerator is 0.5 g / L or more and 50 g / L or less. リン酸およびリン酸塩、ならびにアンモニアおよびアンモニウム塩、からなる群から選択されるエッチング剤をさらに含む、請求項１〜４のいずれか１項に記載の溶接鋼管用防錆処理液。 The rust preventive treatment liquid for welded steel pipes according to any one of claims 1 to 4, further comprising an etching agent selected from the group consisting of phosphoric acid and phosphate, and ammonia and ammonium salt. 前記エッチング剤は、リン酸またはリン酸塩と、アンモニアまたはアンモニウム塩と、をいずれも含む、請求項５に記載の溶接鋼管用防錆処理液。 The rust preventive treatment liquid for welded steel pipes according to claim 5, wherein the etching agent contains both phosphoric acid or phosphate and ammonia or ammonium salt. 前記リン酸またはリン酸塩の含有量は、リン酸アニオン（ＰＯ４ ３−）換算で１ｇ／Ｌ以上であり、かつ、前記アンモニアまたはアンモニウム塩の含有量は、第四級アンモニウムカチオン（ＮＨ４ ＋）換算で１ｇ／Ｌ以上である、請求項６に記載の溶接鋼管用防錆処理液。 The content of the phosphoric acid or phosphate is a phosphate anion (PO 4 3-) converted at 1 g / L or more, and the content of the ammonia or ammonium salt, quaternary ammonium cation (NH 4 + ) The rust preventive treatment liquid for welded steel pipes according to claim 6, which is 1 g / L or more in terms of conversion. 固形分の含有量は２０％以上である、請求項１〜７のいずれか１項に記載の溶接鋼管用防錆処理液。 The rust preventive treatment liquid for welded steel pipes according to any one of claims 1 to 7, wherein the solid content is 20% or more. ｐＨは７．０以上９．５以下である、請求項１〜８のいずれか１項に記載の溶接鋼管用防錆処理液。 The rust preventive treatment liquid for welded steel pipes according to any one of claims 1 to 8, wherein the pH is 7.0 or more and 9.5 or less. 顔料をさらに含有する、請求項１〜９のいずれか１項に記載の溶接鋼管用防錆処理液。 The rust preventive treatment liquid for welded steel pipes according to any one of claims 1 to 9, further containing a pigment. ワックスをさらに含有する、請求項１〜１０のいずれか１項に記載の溶接鋼管用防錆処理液。 The rust preventive treatment liquid for welded steel pipes according to any one of claims 1 to 10, further containing wax. 溶接鋼管の表面と、溶接部または溶接部を覆う溶射補修層と、の両方に、請求項１〜１１のいずれか１項に記載の溶接鋼管用防錆処理液を付与する工程を含む、
溶接鋼管の化成処理方法。 A step of applying the rust preventive treatment liquid for a welded steel pipe according to any one of claims 1 to 11 to both the surface of the welded steel pipe and the thermal spray repair layer covering the welded portion or the welded portion.
Chemical conversion treatment method for welded steel pipes. 前記溶接鋼管用防錆処理液は、溶接鋼管の全周に付与される、請求項１２に記載の溶接鋼管の化成処理方法。 The chemical conversion treatment method for a welded steel pipe according to claim 12, wherein the rust preventive treatment liquid for a welded steel pipe is applied to the entire circumference of the welded steel pipe. 前記溶接鋼管用防錆処理液は、膜厚０．５μｍ以上１０μｍ以下の膜厚で付与される、請求項１２または１３に記載の溶接鋼管の化成処理方法。 The chemical conversion treatment method for welded steel pipes according to claim 12 or 13, wherein the rust preventive treatment liquid for welded steel pipes is applied with a thickness of 0.5 μm or more and 10 μm or less. 溶接鋼管の表面と、溶接部または溶接部を覆う溶射補修層と、の両方の上に、化成処理皮膜を有する溶接鋼管であって、
前記化成処理皮膜は、
フッ素樹脂およびアクリル樹脂を含む有機樹脂と、
ジルコニウム化合物と、
ジエチルアジペート、ジブチルアジペート、ジメチルアジペートおよびｎ−メチル−２−ピロリドンからなる群から選択される１以上の結合促進剤と、
を含む、溶接鋼管。 A welded steel pipe having a chemical conversion coating on both the surface of the welded steel pipe and the welded portion or the thermal spray repair layer covering the welded portion.
The chemical conversion treatment film is
Organic resins including fluororesins and acrylic resins,
With zirconium compounds
With one or more binding promoters selected from the group consisting of diethyl adipate, dibutyl adipate, dimethyl adipate and n-methyl-2-pyrrolidone,
Including welded steel pipe. 溶接鋼管の成形加工によって作製された溶接鋼管の成形加工品であって、
前記溶接鋼管の成形加工品は、溶接鋼管の表面と、溶接部または溶接部を覆う溶射補修層と、の両方の上に化成処理皮膜を有し、
前記化成処理皮膜は、
フッ素樹脂およびアクリル樹脂を含む有機樹脂と、
ジルコニウム化合物と、
ジエチルアジペート、ジブチルアジペート、ジメチルアジペートおよびｎ−メチル−２−ピロリドンからなる群から選択される１以上の結合促進剤と、
を含む、溶接鋼管の成形加工品。 It is a molded product of a welded steel pipe produced by molding a welded steel pipe.
The molded product of the welded steel pipe has a chemical conversion treatment film on both the surface of the welded steel pipe and the thermal spray repair layer covering the welded portion or the welded portion.
The chemical conversion treatment film is
Organic resins including fluororesins and acrylic resins,
With zirconium compounds
With one or more binding promoters selected from the group consisting of diethyl adipate, dibutyl adipate, dimethyl adipate and n-methyl-2-pyrrolidone,
Formed products of welded steel pipes, including.
JP2018009508A 2018-01-24 2018-01-24 Anti-rust treatment liquid for welded steel pipes, chemical conversion treatment methods for welded steel pipes, molded products of welded steel pipes and welded steel pipes Active JP6962216B2 (en)

Priority Applications (5)

Application Number Priority Date Filing Date Title
JP2018009508A JP6962216B2 (en) 2018-01-24 2018-01-24 Anti-rust treatment liquid for welded steel pipes, chemical conversion treatment methods for welded steel pipes, molded products of welded steel pipes and welded steel pipes
CN201980009609.6A CN111630206B (en) 2018-01-24 2019-01-22 Antirust treatment liquid for welded steel pipe, chemical conversion treatment method for welded steel pipe, and welded steel pipe molded product
PCT/JP2019/001821 WO2019146584A1 (en) 2018-01-24 2019-01-22 Anti-rust treatment solution for welded steel pipes, chemical conversion treatment method for welded steel pipe, welded steel pipe and formed product of welded steel pipes
KR1020207021389A KR20200110750A (en) 2018-01-24 2019-01-22 Anti-corrosion treatment liquid for welded steel pipe, chemical treatment method of welded steel pipe, molded product of welded steel pipe and welded steel pipe
TW108102764A TWI791746B (en) 2018-01-24 2019-01-24 Antirust treatment liquid for welded steel pipes, chemical conversion treatment method for welded steel pipes, welded steel pipes and formed products of welded steel pipes

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
JP2018009508A JP6962216B2 (en) 2018-01-24 2018-01-24 Anti-rust treatment liquid for welded steel pipes, chemical conversion treatment methods for welded steel pipes, molded products of welded steel pipes and welded steel pipes

Publications (2)

Publication Number Publication Date
JP2019127618A JP2019127618A (en) 2019-08-01
JP6962216B2 true JP6962216B2 (en) 2021-11-05

Family

ID=67395440

Family Applications (1)

Application Number Title Priority Date Filing Date
JP2018009508A Active JP6962216B2 (en) 2018-01-24 2018-01-24 Anti-rust treatment liquid for welded steel pipes, chemical conversion treatment methods for welded steel pipes, molded products of welded steel pipes and welded steel pipes

Country Status (5)

Country Link
JP (1) JP6962216B2 (en)
KR (1) KR20200110750A (en)
CN (1) CN111630206B (en)
TW (1) TWI791746B (en)
WO (1) WO2019146584A1 (en)

Families Citing this family (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP7127628B2 (en) * 2019-09-10 2022-08-30 Ｊｆｅスチール株式会社 Surface treatment liquid, method for producing surface-treated steel sheet, and surface-treated steel sheet
JPWO2021060294A1 (en) * 2019-09-26 2021-04-01
CN115101862A (en) * 2022-06-10 2022-09-23 江苏睿捷新材料科技有限公司 Corrosion-resistant metal-plastic composite film

Family Cites Families (23)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
NL89112B (en) * 1937-08-04 1900-01-01
NL8001085A (en) * 1979-02-27 1980-08-29 Minnesota Mining & Mfg PHOTOSENSITIVE MATERIALS AND OBJECTS.
JP3376493B2 (en) 1992-01-29 2003-02-10 大日本インキ化学工業株式会社 Aqueous curable resin composition
WO2003074760A1 (en) * 2000-09-07 2003-09-12 Jfe Steel Corporation Surface treated steel sheet and method for production thereof
EP1394229B1 (en) * 2001-05-09 2015-04-08 Daikin Industries, Ltd. Fluorine-containing resin coating compositions, primers for etfe coating, and coated articles
JP2003105563A (en) * 2001-10-01 2003-04-09 Maruyasu Industries Co Ltd Surface treatment structure and surface treatment method of metallic pipe
JP2003201578A (en) * 2002-01-11 2003-07-18 Nippon Parkerizing Co Ltd Chromium-free surface-treated aluminum-zinc based alloy plated steel sheet
JP2003293165A (en) 2002-03-29 2003-10-15 Nisshin Steel Co Ltd Welded steel pipe having excellent corrosion resistance
JP2006010063A (en) * 2004-05-24 2006-01-12 Nippon Steel Corp Resin lined steel pipe with end corrosive protection core and its manufacturing method
TWI272135B (en) * 2005-01-31 2007-02-01 Kobe Steel Ltd Precoated metal sheet and process for producing the same
JP4104637B2 (en) * 2005-11-22 2008-06-18 古河スカイ株式会社 Pre-coated metal plate for slot-in drive case
CN101153196B (en) * 2006-09-27 2012-05-23 大日本油墨化学工业株式会社 Aqueous composition for single rust-proof treatment of metal panel and single rust-proof treatment metal panel
JP5328980B2 (en) 2010-06-18 2013-10-30 日新製鋼株式会社 Chemical conversion treated steel sheet and method for producing the same
JP5328981B2 (en) 2010-06-18 2013-10-30 日新製鋼株式会社 Chemical conversion treated steel sheet and method for producing the same
JP5469556B2 (en) 2010-07-16 2014-04-16 日新製鋼株式会社 Chemical conversion treated steel sheet and method for producing the same
JP5575009B2 (en) 2011-02-25 2014-08-20 日新製鋼株式会社 Formed product of plated steel sheet, method for producing the same, and chemical conversion treatment liquid
JP5595305B2 (en) 2011-02-25 2014-09-24 日新製鋼株式会社 Welded steel pipe
JP5674605B2 (en) * 2011-09-13 2015-02-25 日新製鋼株式会社 Chemical conversion treated steel sheet and method for producing the same
JP6526950B2 (en) * 2013-12-18 2019-06-05 日本パーカライジング株式会社 Water-based metal surface treatment agent, metal surface treatment film and metal material with metal surface treatment film
TW201538309A (en) * 2014-03-27 2015-10-16 Nisshin Steel Co Ltd Chemical conversion steel plate and method for producing the same and chemical conversion liquid
JP5837245B1 (en) * 2014-03-27 2015-12-24 日新製鋼株式会社 Chemical conversion treated steel sheet, method for producing the same, and chemical conversion treatment liquid
TWI725054B (en) * 2015-10-01 2021-04-21 日商三菱鉛筆股份有限公司 Non-aqueous dispersion of fluorine resin, thermosetting resin composition of fluorine resin and its cured product, and adhesive composition for circuit board
JP6271062B1 (en) * 2017-04-26 2018-01-31 日新製鋼株式会社 Water-based treatment liquid, chemical conversion treatment method, and chemical conversion treatment steel plate

Also Published As

Publication number Publication date
CN111630206A (en) 2020-09-04
CN111630206B (en) 2022-04-08
JP2019127618A (en) 2019-08-01
KR20200110750A (en) 2020-09-25
TWI791746B (en) 2023-02-11
WO2019146584A1 (en) 2019-08-01
TW201936991A (en) 2019-09-16

Similar Documents

Publication Publication Date Title
JP5328980B2 (en) Chemical conversion treated steel sheet and method for producing the same
JP5328981B2 (en) Chemical conversion treated steel sheet and method for producing the same
JP5595305B2 (en) Welded steel pipe
JP6962216B2 (en) Anti-rust treatment liquid for welded steel pipes, chemical conversion treatment methods for welded steel pipes, molded products of welded steel pipes and welded steel pipes
JP6271062B1 (en) Water-based treatment liquid, chemical conversion treatment method, and chemical conversion treatment steel plate
JP5674605B2 (en) Chemical conversion treated steel sheet and method for producing the same
JP5575009B2 (en) Formed product of plated steel sheet, method for producing the same, and chemical conversion treatment liquid
JP6962215B2 (en) End face rust preventive treatment liquid for plated steel sheet, chemical conversion treatment method for end face of plated steel sheet, chemical conversion treated steel sheet and molded products
JP5631231B2 (en) Chemical conversion Zn-plated steel sheet and method for producing the same
JP5674606B2 (en) Chemical conversion treated steel sheet and method for producing the same
JP5631239B2 (en) Chemical conversion Al-plated steel sheet and method for producing the same
JP2016079493A (en) Method for manufacturing chemical conversion treated molding

Legal Events

Date Code Title Description
RD02 Notification of acceptance of power of attorney

Free format text: JAPANESE INTERMEDIATE CODE: A7422

Effective date: 20190617

RD04 Notification of resignation of power of attorney

Free format text: JAPANESE INTERMEDIATE CODE: A7424

Effective date: 20191030

A711 Notification of change in applicant

Free format text: JAPANESE INTERMEDIATE CODE: A712

Effective date: 20200901

A621 Written request for application examination

Free format text: JAPANESE INTERMEDIATE CODE: A621

Effective date: 20200918

A131 Notification of reasons for refusal

Free format text: JAPANESE INTERMEDIATE CODE: A131

Effective date: 20210803

A521 Request for written amendment filed

Free format text: JAPANESE INTERMEDIATE CODE: A523

Effective date: 20210826

TRDD Decision of grant or rejection written
A01 Written decision to grant a patent or to grant a registration (utility model)

Free format text: JAPANESE INTERMEDIATE CODE: A01

Effective date: 20210914

A61 First payment of annual fees (during grant procedure)

Free format text: JAPANESE INTERMEDIATE CODE: A61

Effective date: 20210927

R151 Written notification of patent or utility model registration

Ref document number: 6962216

Country of ref document: JP

Free format text: JAPANESE INTERMEDIATE CODE: R151