JP2004010717A

JP2004010717A - Coating material and method of forming coating film using the same

Info

Publication number: JP2004010717A
Application number: JP2002164386A
Authority: JP
Inventors: Akira Setogawa; 瀬戸川　晃; Yasuaki Yamamoto; 山本　康彰
Original assignee: Hitachi Cable Ltd
Current assignee: Hitachi Cable Ltd
Priority date: 2002-06-05
Filing date: 2002-06-05
Publication date: 2004-01-15
Anticipated expiration: 2022-06-05
Also published as: JP3952865B2

Abstract

<P>PROBLEM TO BE SOLVED: To provide a coating material affording the surface of an object member with high abrasion resistance and smoothness when applied on the surface. <P>SOLUTION: The coating material is obtained by blending at least one fluororesin selected from a tetrafluoroethylene-perfluoroalkyl vinyl ether copolymer resin(PFA), an ethylene-tetrafluoroethylene copolymer resin(ETFE) and a tetrafluoroethylene-hexafluoropropylene copolymer resin(FEP) or a polyamide-imide as a coating resin with 5-50 wt.% of a modified fluororesin obtained by irradiating an FEP heated to 80-280°C lower than the melting point of the FEP with radiation under the conditions of ≤13 kPa in oxygen concentration and 1 kGy to 10 MGy in absorption dose. A coating film is formed by coating an object member with this coating material followed by baking the coating material. <P>COPYRIGHT: (C)2004,JPO

Description

【０００１】
【発明の属する技術分野】
本発明は、成形金型の表面塗装等に用いられる塗装材料および塗装材料を用いた塗装膜の形成方法に関する。
【０００２】
【従来の技術】
近年、耐摩耗性に優れた平滑な塗装膜が求められている。例えば、成形金型の表面塗装には、耐摩耗性に優れた平滑な塗装膜が求められている。これは、成形時に金型に成型品の材料を加熱して流し込むために塗装膜の耐摩耗性が必要であり、また成形品表面の凹凸を少なくするために、塗装膜の平滑性が求められるからである。
【０００３】
従来、塗装材料には、テトラフルオロエチレン−パーフルオロアルキルビニルエーテル共重合樹脂（ＰＦＡ）、エチレン−テトラフルオロエチレン共重合樹脂（ＥＴＦＥ）およびテトラフルオロエチレン−ヘキサフルオロプロピレン共重合樹脂（ＦＥＰ）から選ばれる少なくとも一つのふっ素樹脂や、ポリアミドイミドによる塗装用樹脂が使用されてきた。しかし、その塗装用樹脂は、平滑性は良いが耐摩耗性が劣るため摺動部に塗装したときの寿命が短いという欠点があった。
【０００４】
この欠点を解消するために、ＰＦＡ、ＥＴＦＥおよびＦＥＰから選ばれた少なくとも一つの母剤ふっ素樹脂と、融点以上に加熱された未改質ふっ素樹脂に電離性放射線を照射して得られる改質ふっ素樹脂との混合物を塗装し、焼成することにより塗装面の離型性がよく、摩耗量を少なくする（耐摩耗性を向上させる）ことにより、寿命を長くする方法がある。
【０００５】
【発明が解決しようとする課題】
しかし、上述した従来の塗装材料を用いた塗装膜の形成方法においては、塗装面の耐摩耗性が向上するものの、表面粗さが大きいという問題があった。このため例えば、成形金型用の表面塗装材料として用いる場合には、研磨によって塗装面を平滑にする必要があり、金型作製費用が高くなる。
【０００６】
本発明は、かかる点に鑑みてなされたものであり、被塗装部材の表面に塗装した際に優れた耐摩耗性と平滑性とを得ることができる塗装材料および塗装材料を用いた塗装膜の形成方法を提供することを目的とする。
【０００７】
【課題を解決するための手段】
上記課題を解決するために、本発明の塗装材料は、塗装用樹脂と、テトラフルオロエチレン−ヘキサフルオロプロピレン共重合樹脂（ＦＥＰ）を改質した改質ふっ素樹脂とを、５〜５０重量％の割合で混合したことを特徴としている。
【０００８】
また、前記塗装用樹脂は、テトラフルオロエチレン−パーフルオロアルキルビニルエーテル共重合樹脂（ＰＦＡ）、エチレン−テトラフルオロエチレン共重合樹脂（ＥＴＦＥ）およびテトラフルオロエチレン−ヘキサフルオロプロピレン共重合樹脂（ＦＥＰ）から選ばれる少なくとも一つのふっ素樹脂、あるいはポリアミドイミドであることを特徴としている。
【０００９】
また、前記改質ふっ素樹脂は、酸素濃度１３ｋＰａ以下、吸収線量１ｋＧｙ〜１０ＭＧｙの条件で、融点以下の８０〜２８０℃に加熱されたＦＥＰに放射線を照射して得られることを特徴としている。
【００１０】
また、本発明の塗装材料を用いた塗装膜の形成方法は、ＰＦＡ、ＥＴＦＥおよびＦＥＰから選ばれる少なくとも一つのふっ素樹脂、あるいはポリアミドイミドである塗装用樹脂と、酸素濃度１３ｋＰａ以下、吸収線量１ｋＧｙ〜１０ＭＧｙの条件で、融点以下の８０〜２８０℃に加熱されたＦＥＰに放射線を照射して得られる改質ふっ素樹脂とを、５〜５０重量％の割合で混合した塗装材料を、被塗装部材に塗装したのち焼成することを特徴としている。
【００１１】
【発明の実施の形態】
以下、本発明の実施の形態について、図面を参照して詳細に説明する。
【００１２】
（実施の形態）
図１は、本発明の実施の形態に係る塗装材料を平板に塗布した後に剥離した薄膜の一例を示す図である。図２は、本発明の実施の形態に係る塗装材料を円筒内部に塗布した後に剥離した薄膜の一例を示す図である。
【００１３】
図１に示す平板状の薄膜（塗装膜）１０または図２に示す円筒状の薄膜（塗装膜）２０を形成するに塗布した本実施の形態の塗装材料は、後述する塗装用樹脂と改質ふっ素樹脂とを、５〜５０重量％の割合で含有した混合物である。また、薄膜（塗装膜）は、本塗装材料を平板又は円筒の被塗装部材に塗装し、焼成することによって得たものである。
【００１４】
すなわち、本塗装材料は、ＰＦＡ、ＥＴＦＥおよびＦＥＰから選ばれた少なくとも一つのふっ素樹脂、あるいは、ポリアミドイミドの粉末、溶液または分散液に、酸素濃度１３ｋＰａ以下、吸収線量１ｋＧｙ〜１０ＭＧｙの条件で、８０〜２８０℃に加熱されたＦＥＰに放射線を照射して得られる改質ふっ素樹脂粉末を配合して得ることができる。
【００１５】
その放射線としては、未改質フッ素樹脂を架橋反応（高分子などの分子鎖間を化学結合により橋架けする反応）させることができる放射線、例えば電離作用をもつ電離性放射線が好ましい。具体的には、γ線、電子線、Ｘ線、中性子線、あるいは高エネルギーイオン等が挙げられる。
【００１６】
電離性放射線の照射を行なうに際しては、未改質ふっ素樹脂をその結晶融点以下に加熱しておくことが好ましい。すなわち、ＦＥＰの結晶融点である２７５℃よりも低い温度にＰＴＦＥを加熱した状態で電離性放射線を照射することが好ましい。未改質ふっ素樹脂をその融点以上に加熱すると、樹脂が融着し粉砕により、平均粒径１０μｍ以下で最大粒径５０μｍ以下にすることが困難である。ＦＥＰは、他のふっ素樹脂と異なり結晶融点以下に加熱して電離性放射線を照射することで架橋反応が起こるため、平均粒径１０μｍ以下で最大粒径５０μｍ以下の粉砕が可能となる。
【００１７】
電離性放射線の照射条件は、酸素濃度１３ｋＰａ以下、好ましくは１．３ｋＰａ以下の不活性ガス雰囲気下で、未改質フッ素樹脂の吸収線量１ｋＧｙ〜１０ＭＧｙの条件である。酸素濃度１３ｋＰａを越えると放射線照射によって生じたラジカル等が消費され、架橋反応が進まなくなる。また吸収線量１ｋＧｙ以下であると、架橋反応が生じにくくなり、１０ＭＧｙをこえると伸び等の著しい低下をまねく。
【００１８】
上記の改質フッ素樹脂粉末が配合される塗装用樹脂の溶液または分散液は、ＰＦＡ、ＥＴＦＥおよびＦＥＰから選ばれる少なくとも一つのふっ素樹脂あるいは、ポリアミドイミドの単独または混合体を、溶液に溶解または分散させることにより得られる。
【００１９】
このような本実施の形態の塗装材料を実際に製造した場合の実施例と比較例を説明する。
【００２０】
アルミ板にＰＦＡ（ダイキンエ業株式会社製；ＡＣＸ−３１、粒径２５μｍ、融点３０５℃）と、本実施の形態の改質ふっ素樹脂粉末（日立電線社製；微粉化ＸＦＯ、最大粒径２０μｍ）を、樹脂全量に対して、各々１００〜３０容量％と０〜７０容量％配合したものをスプレー塗装し、３６０℃で５０分間焼成し、下記の表１に示す実施例１〜５および比較例１〜３の塗装膜を得た。
【００２１】
また、配合材をＥＴＦＥ（ダイキンエ業株式会社製；ＥＣ−６５２０、粒径５０μｍ、融点２２５℃）とＦＥＰ（ダイキンエ業株式会社製；ＮＣＸ−１、粒径２５μｍ、融点２５０℃）とＰＡＩ（日立化成工業株式会社製：ＨＰＣ−６０００Ａ、粘度１３００ｍＰａ・ｓ／２５℃）に変えて同様に、下記表２に示す実施例６〜１５および比較例４〜９の塗装膜を得た。なお、塗装膜の厚さは４０〜８０μｍであった。
【００２２】
得られた塗装膜の表面粗さを測定したあと、表面粗さをＲａ０．２μｍに研摩したＳＵＳ３０４製のリング表面に当て、リングオンディスク試験により相対摩耗量を評価した。試験条件は、速度が１０．８ｍ／ｍｉｎ、測定温度が２５℃、荷重が９８０Ｎ、測定時間が３０分である。測定結果を同表１、２に示す。
【００２３】
【表１】

【表２】

表１には塗装用樹脂をＰＦＡとした場合の検討結果を示した。実施例１から実施例５に示すように、微粉化ＸＦＯの配合割合は、塗膜全体に対して、５〜５０容量％の場合に表面粗さと相対摩耗量が良好になる。比較例１と比較例２に示したように、微粉化ＸＦＯの配合割合が５０容量％をこえると表面均一な塗膜が得られにくく、相対摩耗量が大きくなる。また、比較例３に示したように、微粉化ＸＦＯの配合割合が５容量％未満であると耐摩耗性、耐久性が向上しない。比較例４と比較例５に示したように、ＸＦＯを配合した場合には、相対摩耗量は微粉化ＸＦＯを配合した場合と同じであるが、研摩なしでは表面粗さが大きくなる。
【００２４】
表２には塗装用樹脂をＥＴＦＥ、ＦＥＰおよびＰＡＩとした場合の検討結果を示した。実施例６から実施例８に示したように、微粉化ＸＦＯを配合することによって、表面粗さと相対摩耗量が良好になる。配合割合は、塗膜全体に対して、５〜５０容量％が好ましい。比較例６から比較例８に示すように、微粉化ＸＦＯの配合割合が５０容量％を越えると表面均一な塗膜が得られにくく、相対摩耗量が大きくなる。
【００２５】
また、比較例９から比較例１１に示したように、微粉化ＸＦＯの配合割合が５容量％未満であると耐摩耗性、耐久性が向上しない。比較例１２から比較例１４に示したようにＸＦＯを配合した場合には、相対摩耗量は微粉化ＸＦＯを配合した場合と同じであるが、研摩なしでは表面粗さが大きくなる。
【００２６】
このように、本実施の形態の塗装材料および塗装材料を用いた塗装膜の形成方法によれば、まず、ＰＦＡ、ＥＴＦＥおよびＦＥＰから選ばれる少なくとも一つのふっ素樹脂、あるいはポリアミドイミドである塗装用樹脂と、酸素濃度１３ｋＰａ以下、吸収線量１ｋＧｙ〜１０ＭＧｙの条件で、融点以下の８０〜２８０℃に加熱されたＦＥＰに放射線を照射して得られる改質ふっ素樹脂とを、５〜５０重量％の割合で混合することで塗装材料を得た。
【００２７】
このようにして得られた塗装材料は、含まれる改質ふっ素樹脂が平均粒径１０μｍ以下で最大粒径５０μｍ以下の改質ふっ素樹脂粉末なので、塗装膜への分散性や樹脂塗膜との密着性に優れたものとなる。
【００２８】
従って、この塗装材料を、被塗装部材に塗装したのち焼成することにより得られる塗装膜は、耐摩耗性が高く、研磨することなく塗装膜の表面粗さを塗装用樹脂と同等以下にすることができる。例えば、成形金型用の表面塗装材料として用いた場合には、従来のような研磨による塗装面の平滑化が不要なので、金型作製費を安価にすることができる。
【００２９】
【発明の効果】
以上説明したように、本発明によれば、ＰＦＡ、ＥＴＦＥおよびＦＥＰから選ばれる少なくとも一つのふっ素樹脂、あるいはポリアミドイミドである塗装用樹脂と、酸素濃度１３ｋＰａ以下、吸収線量１ｋＧｙ〜１０ＭＧｙの条件で、融点以下の８０〜２８０℃に加熱されたＦＥＰに放射線を照射して得られる改質ふっ素樹脂とを、５〜５０重量％の割合で混合した塗装材料を得るようにした。この塗装材料は、含まれる改質ふっ素樹脂が平均粒径１０μｍ以下で最大粒径５０μｍ以下の改質ふっ素樹脂粉末なので、塗装膜への分散性や樹脂塗膜との密着性に優れたものとなる。従って、この塗装材料を、被塗装部材に塗装したのち焼成することにより塗装膜を形成すると、優れた耐摩耗性と平滑性とを有する塗装膜となる。
【図面の簡単な説明】
【図１】本発明の実施の形態に係る塗装材料を平板に塗布した後に剥離した薄膜の一例を示す図である。
【図２】本発明の実施の形態に係る塗装材料を円筒内部に塗布した後に剥離した薄膜の一例を示す図である。
【符号の説明】
１０　平板状の薄膜（塗装膜）
２０　円筒状の薄膜（塗装膜）[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a coating material used for surface coating of a molding die, and a method for forming a coating film using the coating material.
[0002]
[Prior art]
In recent years, a smooth coating film having excellent wear resistance has been demanded. For example, a surface coating of a molding die requires a smooth coating film having excellent wear resistance. This is because the coating material must have abrasion resistance in order to heat and pour the material of the molded product into the mold during molding, and the smoothness of the coating film is required in order to reduce unevenness on the molded product surface. Because.
[0003]
Conventionally, the coating material is selected from tetrafluoroethylene-perfluoroalkyl vinyl ether copolymer resin (PFA), ethylene-tetrafluoroethylene copolymer resin (ETFE), and tetrafluoroethylene-hexafluoropropylene copolymer resin (FEP). At least one fluororesin or a polyamide-imide coating resin has been used. However, the coating resin has a problem that the service life when coated on a sliding portion is short because the coating resin has good smoothness but poor abrasion resistance.
[0004]
In order to solve this drawback, at least one base fluororesin selected from PFA, ETFE and FEP, and a modified fluororesin obtained by irradiating an unmodified fluororesin heated to a melting point or higher with ionizing radiation. There is a method in which a mixture with a resin is applied and baked so that the releasability of the coated surface is good, and the life is prolonged by reducing the amount of wear (improving wear resistance).
[0005]
[Problems to be solved by the invention]
However, in the above-described conventional method of forming a coating film using a coating material, there is a problem that although the wear resistance of the coated surface is improved, the surface roughness is large. For this reason, for example, when used as a surface coating material for a molding die, it is necessary to smooth the painted surface by polishing, and the production cost of the die increases.
[0006]
The present invention has been made in view of such a point, a coating material that can obtain excellent wear resistance and smoothness when coated on the surface of a member to be coated, and a coating film using the coating material. An object is to provide a forming method.
[0007]
[Means for Solving the Problems]
In order to solve the above problems, a coating material of the present invention comprises a coating resin and a modified fluororesin obtained by modifying a tetrafluoroethylene-hexafluoropropylene copolymer resin (FEP) in an amount of 5 to 50% by weight. It is characterized by being mixed in proportions.
[0008]
The coating resin is selected from tetrafluoroethylene-perfluoroalkylvinyl ether copolymer resin (PFA), ethylene-tetrafluoroethylene copolymer resin (ETFE), and tetrafluoroethylene-hexafluoropropylene copolymer resin (FEP). At least one fluororesin or polyamideimide.
[0009]
Further, the modified fluororesin is obtained by irradiating FEP heated to 80 to 280 ° C. below the melting point under an oxygen concentration of 13 kPa or less and an absorbed dose of 1 kGy to 10 MGy.
[0010]
In addition, the method for forming a coating film using the coating material of the present invention includes a coating resin which is at least one fluororesin selected from PFA, ETFE and FEP, or a polyamideimide, an oxygen concentration of 13 kPa or less, and an absorbed dose of 1 kGy or less. A coating material obtained by irradiating FEP heated to 80 to 280 ° C. below the melting point with radiation under a condition of 10 MGy at a ratio of 5 to 50% by weight with a modified fluororesin is applied to a member to be coated. It is characterized by firing after painting.
[0011]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.
[0012]
(Embodiment)
FIG. 1 is a diagram illustrating an example of a thin film that is peeled after a coating material according to an embodiment of the present invention is applied to a flat plate. FIG. 2 is a diagram illustrating an example of a thin film that is peeled after the coating material according to the embodiment of the present invention is applied inside a cylinder.
[0013]
The coating material of the present embodiment applied to form the flat thin film (coating film) 10 shown in FIG. 1 or the cylindrical thin film (coating film) 20 shown in FIG. It is a mixture containing a fluororesin in a ratio of 5 to 50% by weight. The thin film (coating film) is obtained by applying the present coating material to a flat or cylindrical member to be coated and firing it.
[0014]
That is, the present coating material is added to at least one fluororesin selected from PFA, ETFE and FEP, or a polyamideimide powder, solution or dispersion under the conditions of an oxygen concentration of 13 kPa or less and an absorbed dose of 1 kGy to 10 MGy. It can be obtained by blending a modified fluororesin powder obtained by irradiating radiation to FEP heated to -280 ° C.
[0015]
The radiation is preferably a radiation capable of causing a cross-linking reaction (a reaction of bridging between molecular chains of a polymer or the like by a chemical bond) of an unmodified fluororesin, for example, an ionizing radiation having an ionizing action. Specific examples include γ-rays, electron beams, X-rays, neutron beams, and high energy ions.
[0016]
When irradiating with ionizing radiation, it is preferable to heat the unmodified fluororesin below its crystalline melting point. That is, it is preferable to irradiate ionizing radiation with PTFE heated to a temperature lower than the crystal melting point of FEP, 275 ° C. If the unmodified fluororesin is heated above its melting point, the resin will fuse and it is difficult to reduce the average particle diameter to 10 μm or less and the maximum particle diameter to 50 μm or less by pulverization. Unlike other fluororesins, FEP is heated to a temperature lower than the crystal melting point and irradiated with ionizing radiation to cause a cross-linking reaction, so that pulverization with an average particle size of 10 μm or less and a maximum particle size of 50 μm or less is possible.
[0017]
The ionizing radiation is irradiated under an inert gas atmosphere having an oxygen concentration of 13 kPa or less, preferably 1.3 kPa or less, under an absorbed dose of 1 kGy to 10 MGy of the unmodified fluororesin. If the oxygen concentration exceeds 13 kPa, radicals and the like generated by radiation irradiation are consumed, and the crosslinking reaction does not proceed. When the absorbed dose is 1 kGy or less, a crosslinking reaction hardly occurs. When the absorbed dose exceeds 10 MGy, elongation and the like are remarkably reduced.
[0018]
The solution or dispersion of the coating resin containing the modified fluororesin powder is at least one fluororesin selected from PFA, ETFE and FEP, or a single or mixture of polyamideimide dissolved or dispersed in the solution. It is obtained by doing.
[0019]
Examples and comparative examples in which the coating material of the present embodiment is actually manufactured will be described.
[0020]
Aluminum plate with PFA (manufactured by Daikin Industries, Ltd .; ACX-31, particle size 25 μm, melting point 305 ° C.) and modified fluororesin powder of the present embodiment (manufactured by Hitachi Cable, Ltd .; finely divided XFO, maximum particle size 20 μm) Was spray-coated with 100 to 30% by volume and 0 to 70% by volume, respectively, based on the total amount of the resin, and baked at 360 ° C. for 50 minutes. Examples 1 to 5 and Comparative Examples shown in Table 1 below 1 to 3 coating films were obtained.
[0021]
The compounding materials were ETFE (manufactured by Daikin Industries, Ltd .; EC-6520, particle size 50 μm, melting point 225 ° C.), FEP (manufactured by Daikin Industries, Ltd .; NCX-1, particle size 25 μm, melting point 250 ° C.) and PAI (Hitachi, Ltd.) Similarly, coating films of Examples 6 to 15 and Comparative Examples 4 to 9 shown in Table 2 below were obtained by changing to Kasei Kogyo Co., Ltd .: HPC-6000A, viscosity 1300 mPa · s / 25 ° C.). In addition, the thickness of the coating film was 40 to 80 μm.
[0022]
After measuring the surface roughness of the obtained coating film, it was applied to a SUS304 ring surface polished to a surface roughness of Ra 0.2 μm, and the relative wear amount was evaluated by a ring-on-disk test. The test conditions are a speed of 10.8 m / min, a measurement temperature of 25 ° C., a load of 980 N, and a measurement time of 30 minutes. Tables 1 and 2 show the measurement results.
[0023]
[Table 1]

[Table 2]

Table 1 shows the examination results when the coating resin was PFA. As shown in Examples 1 to 5, when the mixing ratio of the finely powdered XFO is 5 to 50% by volume with respect to the whole coating film, the surface roughness and the relative wear amount become good. As shown in Comparative Examples 1 and 2, when the mixing ratio of the finely divided XFO exceeds 50% by volume, it is difficult to obtain a coating film having a uniform surface, and the relative wear amount increases. Further, as shown in Comparative Example 3, when the mixing ratio of the finely divided XFO is less than 5% by volume, the wear resistance and the durability are not improved. As shown in Comparative Examples 4 and 5, when XFO is blended, the relative wear amount is the same as when finely powdered XFO is blended, but the surface roughness increases without polishing.
[0024]
Table 2 shows the results of studies when the coating resins were ETFE, FEP and PAI. As shown in Example 6 to Example 8, the surface roughness and the relative wear amount are improved by mixing the finely powdered XFO. The compounding ratio is preferably 5 to 50% by volume based on the entire coating film. As shown in Comparative Examples 6 to 8, when the mixing ratio of the finely powdered XFO exceeds 50% by volume, it is difficult to obtain a coating film having a uniform surface, and the relative wear amount increases.
[0025]
Further, as shown in Comparative Examples 9 to 11, when the mixing ratio of the finely divided XFO is less than 5% by volume, the wear resistance and the durability are not improved. When XFO is blended as shown in Comparative Examples 12 to 14, the relative wear amount is the same as when finely powdered XFO is blended, but the surface roughness increases without polishing.
[0026]
As described above, according to the coating material of the present embodiment and the method of forming a coating film using the coating material, first, at least one fluororesin selected from PFA, ETFE, and FEP, or a coating resin that is polyamideimide. And a modified fluororesin obtained by irradiating FEP heated to 80 to 280 ° C. below the melting point under the conditions of an oxygen concentration of 13 kPa or less and an absorbed dose of 1 kGy to 10 MGy in a proportion of 5 to 50% by weight. To obtain a coating material.
[0027]
In the coating material thus obtained, the modified fluororesin contained has a mean particle size of 10 μm or less and a maximum particle size of 50 μm or less. It will be excellent in property.
[0028]
Therefore, a coating film obtained by applying this coating material to a member to be coated and then firing the coating material has high abrasion resistance, and the surface roughness of the coating film must be equal to or less than that of the coating resin without polishing. Can be. For example, when it is used as a surface coating material for a molding die, it is not necessary to smooth the coated surface by polishing as in the conventional case, so that the die manufacturing cost can be reduced.
[0029]
【The invention's effect】
As described above, according to the present invention, at least one fluororesin selected from PFA, ETFE, and FEP, or a coating resin that is polyamideimide, an oxygen concentration of 13 kPa or less, and an absorbed dose of 1 kGy to 10 MGy, A coating material was obtained in which a modified fluororesin obtained by irradiating FEP heated to 80 to 280 ° C. below the melting point with radiation was mixed at a ratio of 5 to 50% by weight. Since this coating material contains modified fluororesin powder with an average particle size of 10 μm or less and a maximum particle size of 50 μm or less, the coating material has excellent dispersibility to the coating film and excellent adhesion to the resin coating film. Become. Therefore, when this coating material is applied to a member to be coated and then fired to form a coating film, the coating film has excellent wear resistance and smoothness.
[Brief description of the drawings]
FIG. 1 is a diagram showing an example of a thin film that is peeled after a coating material according to an embodiment of the present invention is applied to a flat plate.
FIG. 2 is a view showing an example of a thin film that is peeled after a coating material according to an embodiment of the present invention is applied inside a cylinder.
[Explanation of symbols]
10. Flat thin film (painted film)
20 Cylindrical thin film (painted film)

Claims

A coating material comprising a coating resin and a modified fluororesin obtained by modifying a tetrafluoroethylene-hexafluoropropylene copolymer resin (FEP) at a ratio of 5 to 50% by weight.

The coating resin is at least one selected from tetrafluoroethylene-perfluoroalkylvinyl ether copolymer resin (PFA), ethylene-tetrafluoroethylene copolymer resin (ETFE), and tetrafluoroethylene-hexafluoropropylene copolymer resin (FEP). The coating material according to claim 1, wherein the coating material is one fluororesin or a polyamideimide.

The modified fluororesin is obtained by irradiating FEP heated to 80 to 280 ° C. below the melting point under an oxygen concentration of 13 kPa or less and an absorbed dose of 1 kGy to 10 MGy, according to claim 1, wherein Coating material described.

At least one fluororesin selected from PFA, ETFE and FEP, or a coating resin which is a polyamideimide, and FEP heated to 80 to 280 ° C. below the melting point under conditions of an oxygen concentration of 13 kPa or less and an absorbed dose of 1 kGy to 10 MGy. A coating film using a coating material, characterized in that a coating material obtained by mixing a modified fluororesin obtained by irradiating a coating material at a ratio of 5 to 50% by weight is coated on a member to be coated and then fired. Formation method.