JP2010115902A - Coated steel sheet and case for electronic device manufactured by using the same - Google Patents
Coated steel sheet and case for electronic device manufactured by using the same Download PDFInfo
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- JP2010115902A JP2010115902A JP2008292366A JP2008292366A JP2010115902A JP 2010115902 A JP2010115902 A JP 2010115902A JP 2008292366 A JP2008292366 A JP 2008292366A JP 2008292366 A JP2008292366 A JP 2008292366A JP 2010115902 A JP2010115902 A JP 2010115902A
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- 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
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- 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
- B05D2202/00—Metallic substrate
- B05D2202/10—Metallic substrate based on Fe
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- 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
- B05D7/50—Multilayers
- B05D7/52—Two layers
- B05D7/54—No clear coat specified
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- Engineering & Computer Science (AREA)
- Wood Science & Technology (AREA)
- Casings For Electric Apparatus (AREA)
- Laminated Bodies (AREA)
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Abstract
Description
本発明は、2層以上の塗膜からなる塗膜層を備える塗装鋼板およびこれを用いてなる電子機器用筐体に関し、詳しくは、2層以上の塗膜からなり、総膜厚が10μm以下の塗膜層を備え、塗装面の耐食性が向上された塗装鋼板、およびこの耐食性が向上された塗膜層を備える側の塗装面を機器の外側とする電子機器用筐体、具体的には液晶テレビ、有機ELテレビ、プラズマテレビのような薄型テレビ用パネルで代表されるAV機器用筐体に関する。 The present invention relates to a coated steel sheet provided with a coating film layer comprising two or more coating films and an electronic device casing using the same, and more specifically, comprises two or more coating films and has a total film thickness of 10 μm or less. A coated steel sheet with improved coating surface corrosion resistance, and an electronic device casing having the coated surface on the side with the coating layer with improved corrosion resistance as the outside of the device, specifically, The present invention relates to a housing for AV equipment typified by a thin TV panel such as a liquid crystal TV, an organic EL TV and a plasma TV.
塗装鋼板(プレコート鋼板、PCMとも呼ばれる)は、基材鋼板に塗装および焼付けにより塗膜を形成した後、コイル状に巻き取られ、その状態でユーザーに納入される。ユーザーは、コイルを巻き戻して、打ち抜き、折り曲げ、絞り加工、またはこれらを組み合わせた加工を行って製品化する。作業環境を悪化させ、廃液処理が面倒な塗装作業をユーザーが行う必要がないことから、塗装鋼板の適用は多くの分野に普及している。 A coated steel plate (also referred to as pre-coated steel plate or PCM) is coated and baked on a base steel plate, wound up in a coil shape, and delivered to the user in that state. The user unwinds the coil and performs punching, bending, drawing, or a combination thereof to produce a product. The application of coated steel sheets is widespread in many fields because the user does not need to perform painting work that makes the working environment worse and waste liquid treatment is troublesome.
塗装鋼板の製造は、基材鋼板(典型的には亜鉛めっきと亜鉛合金めっきとを含む亜鉛系めっき鋼板)に、前処理として化成処理を施した後、下塗り塗料(プライマー)の塗布と焼付け、次に上塗り塗料の塗布と焼付けを順に行う2コート2ベーク方式が一般的である。ただし、最終製品の外側となる「おもて面」とは反対側の「裏面」側については、前処理後に裏面用に開発された塗料を用いて1コート1ベーク方式で塗装が行われることもある。 The production of the coated steel sheet is performed by subjecting a base steel sheet (typically a zinc-based plated steel sheet including zinc plating and zinc alloy plating) to a chemical conversion treatment as a pretreatment, and then applying and baking an undercoat paint (primer). Next, a two-coat two-bake method is generally performed in which a top coat is applied and baked in order. However, on the “back side” opposite to the “front side”, which is the outside of the final product, coating is performed in a 1-coat 1-bake method using the paint developed for the back side after the pretreatment. There is also.
塗装鋼板は、耐食性(塗膜の端部における白錆および/または赤錆発生の抑制)、加工性、塗膜硬度(耐傷つき性)、耐汚染性、耐薬品性、耐候性などの多くの性能をいずれについても高いレベルで達成することが要求されるが、近年は、コスト削減の観点に加え、環境対策の観点や塗装作業の合理化の観点からも、塗装鋼板における意匠性等が要求される品質保障面に形成される塗膜に関しても塗膜全体の膜厚(塗膜厚)を薄膜化することが求められてきており、具体的には、10μm以下とすることが一つの目標となってきている。塗膜厚が薄くなると、塗装焼き付け時に発生する有機溶剤を燃焼させるために使用しているインシネーターの負担を低減するとともに、そこから排出されるCO2の低減が可能となる。また、塗膜焼き付け時に排出される有機溶剤の量は、塗膜厚に依存していることから、塗膜厚が薄くなるとインシネーターの範囲内でラインスピードを高めることができ、塗装作業を合理化することが可能となる。 Painted steel sheet has many performances such as corrosion resistance (suppression of white rust and / or red rust at the edge of the coating), workability, coating hardness (scratch resistance), stain resistance, chemical resistance, weather resistance, etc. However, in recent years, in addition to cost reduction, environmental design and rationalization of painting work, the design of coated steel sheets is required. Regarding the coating film formed on the quality assurance side, it has been required to reduce the film thickness (coating film thickness) of the entire coating film, and specifically, one target is to make it 10 μm or less. It is coming. When the coating film thickness is reduced, it is possible to reduce the burden on the insulator used to burn the organic solvent generated during paint baking, and to reduce the CO 2 discharged therefrom. In addition, the amount of organic solvent discharged during coating baking depends on the coating thickness, so as the coating thickness decreases, the line speed can be increased within the range of the incinerator, and the painting work is streamlined. It becomes possible to do.
しかし、前述のように塗膜厚が薄くなると、上記のような多くの性能を高いレベルで、かつバランスよく達成することは困難となってくる。例えば、塗膜厚が薄くなると明度の安定性ならびに素地色および素地疵の隠蔽性を確保することが通常は困難となるため、この点を改善させることを目的とした発明が特許文献1に開示されている。
本発明者が従来技術に係る塗膜について評価したところ、塗膜厚が10μm以下の場合には、上記のような塗膜性能の確保が困難となるばかりでなく、塗膜自体を水分等が透過する現象が顕著となる場合があることが明らかとなった。具体的には、亜鉛系めっき鋼板(犠牲防食のために設けられた亜鉛を含むめっき層が形成された鋼板の総称であって、めっき方法やその組成、合金化処理の有無は問わない。)からなる素地基板上に従来技術に係る塗膜が10μm以下の厚さで形成された塗装鋼板について塩水噴霧試験を行うと、なんら疵がつけられていなくとも、240時間の塩水噴霧試験後の塗装面に白錆が発生する場合があることが明らかとなった。 When the inventor evaluated the coating film according to the prior art, when the coating film thickness is 10 μm or less, not only is it difficult to ensure the above-mentioned coating film performance, but the coating film itself has moisture or the like. It has become clear that the phenomenon of transmission may be noticeable. Specifically, a zinc-based plated steel sheet (a general term for steel sheets on which a plated layer containing zinc provided for sacrificial corrosion protection is formed, regardless of the plating method, its composition, and the presence or absence of alloying treatment). When a salt spray test is performed on a coated steel sheet in which a coating film according to the prior art is formed on a base substrate made of a material having a thickness of 10 μm or less, the coating after the salt spray test for 240 hours is performed without any wrinkles. It became clear that white rust may occur on the surface.
そこで、本発明は、塗膜厚が10μm以下の薄膜であっても、このような塗装面の耐食性(以下、塗膜の端部における耐食性と区別するために「平面部耐食性」という。)の低下をもたらすことなく、しかも加工性を維持することができ、好ましくは色調の安定性を高度に実現する塗装鋼板、およびそのような塗装鋼板を用いてなる電子機器用筐体を提供することを目的とする。 Therefore, the present invention has such a coating surface corrosion resistance (hereinafter referred to as “planar portion corrosion resistance” in order to distinguish it from the corrosion resistance at the end of the coating film) even for a thin film having a coating thickness of 10 μm or less. It is possible to provide a coated steel sheet that can maintain workability without causing deterioration, and preferably achieves high color tone stability, and a casing for an electronic device using such a coated steel sheet. Objective.
上記課題を解決すべく、本発明者が検討を行った結果、次のような知見が得られた。
(A)平面部耐食性が特に求められるのは使用時に外側をなす面、すなわちおもて面となる面の塗膜であり、おもて面の塗膜は一般に複数の塗膜が積層してなる層状の塗膜(以下「塗膜層」という。)で構成されるところ、このような塗膜層を有する塗装鋼板の平面部耐食性を向上させるための対策として、大きく二つの考え方がある。
As a result of studies conducted by the present inventors in order to solve the above problems, the following knowledge was obtained.
(A) The surface portion is particularly required to have corrosion resistance on the outside surface during use, that is, the coating film on the front surface, and the coating film on the front surface is generally formed by laminating a plurality of coating films. As a countermeasure for improving the flat surface corrosion resistance of a coated steel sheet having such a coating film layer, there are mainly two ways of thinking.
すなわち、(1)塗膜層のうち最外層をなす塗膜(以下、「最外層塗膜」という。)の硬度を高めて最外層塗膜のバリア性を高めること、および(2)塗膜層のうち最外層塗膜以外の塗膜(以下、この塗膜を「下層塗膜」と総称する。)を構成する塗膜のうち少なくとも一つの塗膜に用いる防錆顔料の防錆機能を特に高めることである。なお、本発明において、「最外層塗膜」は、いわゆる「クリア塗膜」や「オーバーコート」と呼ばれるような保護用途のみの塗膜を含まないものとして定義され、そのような塗膜はこの最外層塗膜の上に必要に応じてさらに形成される。また、「下層塗膜」は、化成処理により形成される化成皮膜のような塗装下地処理を含まないものとして定義される。 That is, (1) increasing the hardness of the outermost coating film (hereinafter referred to as “outermost coating film”) by increasing the hardness of the outermost coating film, and (2) the coating film. The antirust function of the anticorrosive pigment used for at least one of the coating films constituting the coating film other than the outermost coating film (hereinafter, this coating film is collectively referred to as “lower coating film”) among the layers. Especially to increase. In the present invention, the “outermost layer coating film” is defined as not including a coating film only for protective use, so-called “clear coating film” or “overcoat”. It is further formed on the outermost layer coating film as necessary. In addition, the “lower coating film” is defined as not including a coating ground treatment such as a chemical conversion film formed by chemical conversion treatment.
(B)これらの対策のうち、最外層塗膜のバリア性を高める対策では、最外層塗膜の硬度が高くなるためクラックが発生しやすくなり、塗膜としての加工性(プレス成形性など)が低下してしまう。 (B) Among these countermeasures, the countermeasure for increasing the barrier property of the outermost layer coating film is likely to generate cracks because the hardness of the outermost layer coating film is increased, and the workability as a coating film (press formability, etc.) Will fall.
(C)したがって、下層塗膜を構成する塗膜のうち少なくとも一つの塗膜に特に防錆機能に優れた防錆顔料を含有させることとし、一方、最外層塗膜は硬度を高めるのではなく、むしろ最表面のヤング率を抑えて加工性を確保することが、平面部耐食性の向上とともに加工性を両立しうる対策として好ましい。 (C) Therefore, at least one of the coatings constituting the lower layer coating should contain an anticorrosive pigment having an especially excellent antirust function, while the outermost layer coating does not increase the hardness. Rather, it is preferable to suppress the Young's modulus of the outermost surface and ensure the workability as a measure that can improve both the corrosion resistance of the flat surface and the workability.
(D)このように下層塗膜を構成する塗膜のうち少なくとも一つの塗膜に特に防錆機能に優れた防錆顔料を含有させることにより、下層塗膜の厚みを薄くすることが可能となる。そして、その結果最外層塗膜を相対的に厚くすることができる。最外層塗膜の膜厚が増加すればするほど下層塗膜の膜厚の変動は色調の変化として現れにくくなるため、塗膜層としての色調はより安定化する。 (D) In this way, it is possible to reduce the thickness of the lower coating film by including at least one of the coating films constituting the lower coating film with a rust-preventing pigment having an especially excellent anti-rust function. Become. As a result, the outermost layer coating film can be made relatively thick. As the film thickness of the outermost layer coating film increases, the change in film thickness of the lower layer coating film is less likely to appear as a change in color tone, so that the color tone as the coating layer becomes more stable.
以上の知見に基づき完成された本発明は次のとおりである。
(1)2層以上の塗膜からなる塗膜層を化成処理がなされた面上に備える塗装鋼板であって、前記塗膜層の厚さが10μm以下であり、前記2層以上の塗膜のうち最外層をなす塗膜である最外層塗膜が、塗料固形分に対して5質量%以上50質量%以下の着色顔料を含むとともに、膜厚が2μm以上かつ塗膜最表面のヤング率が5GPa以下であって、前記最外層塗膜以外の塗膜である下層塗膜が、塗料固形分に対して5質量%以上30質量%以下の顔料を含むとともに膜厚が2μm以上である塗膜を備え、当該塗膜に含有される顔料が、吸油量:100ml/100g以上1000ml/100g以下かつ比表面積:100m2/g以上1000m2/g以下を満たす防錆顔料としての多孔質シリカを、塗料固形分に対して5質量%以上30質量%以下含むことを特徴とする塗装鋼板。
The present invention completed based on the above knowledge is as follows.
(1) A coated steel sheet provided with a coating layer comprising two or more coating layers on a surface subjected to chemical conversion treatment, wherein the coating layer has a thickness of 10 μm or less, and the two or more coating layers The outermost coating film, which is the coating film forming the outermost layer, contains a coloring pigment of 5% by mass or more and 50% by mass or less with respect to the solid content of the paint, and has a film thickness of 2 μm or more and the Young's modulus of the outermost surface of the coating film 5 GPa or less, and the lower layer coating film other than the outermost layer coating film contains a pigment in an amount of 5% by mass to 30% by mass with respect to the solid content of the paint and has a film thickness of 2 μm or more. A porous silica as a rust preventive pigment provided with a film, wherein the pigment contained in the coating film satisfies the oil absorption amount: 100 ml / 100 g or more and 1000 ml / 100 g or less and the specific surface area: 100 m 2 / g or more and 1000 m 2 / g or less. , 5 mass% or more with respect to the solid content of the paint 30 Coated steel sheet, which comprises an amount percent.
ここで、「塗料固形分」とは塗料を焼き付けた際の固形分(塗膜)をいい、その質量は次のようにして計測される。すなわち、所定量の塗料または塗料原料(主樹脂等)をオーブンに入れ、その質量を計測しながらオーブン内を加熱して塗料または塗料原料を固化させる。オーブン内の質量変化がなくなるまで固化させたときの固化物の質量計測値を塗料固形分の質量と定義する。 Here, “paint solid content” refers to the solid content (coating film) when the paint is baked, and its mass is measured as follows. That is, a predetermined amount of paint or paint raw material (main resin or the like) is placed in an oven, and the inside of the oven is heated while measuring its mass to solidify the paint or paint raw material. The mass measurement value of the solidified product when solidified until there is no mass change in the oven is defined as the mass of the solid content of the paint.
(2)前記下層塗膜の一つに含有される顔料が、チタニアおよびカーボンブラックから選ばれる一種または二種からなる着色顔料を含む上記(1)記載の塗装鋼板。 (2) The coated steel sheet according to the above (1), wherein the pigment contained in one of the lower layer coating films contains one or two color pigments selected from titania and carbon black.
(3)前記最外層塗膜の膜厚が、前記下層塗膜の膜厚以上である上記(1)または(2)に記載の塗装鋼板。 (3) The coated steel sheet according to (1) or (2), wherein a film thickness of the outermost layer coating film is equal to or greater than a film thickness of the lower layer coating film.
(4)塗装基材が合金化溶融亜鉛めっき鋼板であり、前記塗膜層が形成された面の裏面からの熱放射率が40%以上である上記(1)から(3)のいずれかに記載の塗装鋼板。 (4) The coating substrate is an alloyed hot-dip galvanized steel sheet, and the thermal emissivity from the back surface of the surface on which the coating film layer is formed is 40% or more. The coated steel sheet described.
(5)前記裏面に無機被覆および無機有機複合被覆から選ばれる一種または二種を1層以上有する被覆層を備える上記(1)から(4)のいずれかに記載の塗装鋼板。 (5) The coated steel sheet according to any one of (1) to (4), wherein the back surface is provided with a coating layer having one or more selected from inorganic coating and inorganic-organic composite coating.
(6)前記被覆層の付着量の合計が10mg/m2以上1000mg/m2以下である上記(5に)記載の塗装鋼板。 (6) The coated steel sheet as described in (5) above, wherein the total amount of the coating layer adhered is 10 mg / m 2 or more and 1000 mg / m 2 or less.
(7)上記(1)から(6)のいずれかに記載の塗装鋼板を用いてなる電子機器用筐体であって、前記塗膜層が形成された面が当該筐体の外側をなす面であることを特徴とする電子機器用筐体。 (7) A casing for electronic equipment using the coated steel sheet according to any one of (1) to (6) above, wherein the surface on which the coating film layer is formed forms the outside of the casing A housing for electronic equipment, characterized by being
本発明に係る塗装鋼板は、10μm以下の膜厚でありながら、平面部耐食性および加工性に優れ、しかも色調の安定性に優れうる。したがって、かかる塗装鋼板を用いることで、すぐれた平面部耐食性と意匠性とを有しつつ、環境に配慮したものであって、しかも生産性が高い電子機器用筐体を提供することが可能となる。 Although the coated steel sheet according to the present invention has a film thickness of 10 μm or less, it can be excellent in flat surface corrosion resistance and workability, and can be excellent in color tone stability. Therefore, by using such a coated steel sheet, it is possible to provide a casing for an electronic device that is environmentally friendly and has high productivity while having excellent flat surface corrosion resistance and designability. Become.
以下、本発明に係る塗装鋼板およびこれを用いてなる電子機器用筐体について説明する。
1.基材鋼板
本発明の塗装鋼板に用いられる基材鋼板は特に制限されず、一般的に塗装鋼板に使用される亜鉛を含有するめっき層を有する亜鉛系めっき鋼板、すなわち、亜鉛めっき鋼板もしくは亜鉛合金めっき鋼板またはこれらのめっきを基板と合金化させた合金化めっき鋼板を用いてもよい。
Hereinafter, a coated steel sheet according to the present invention and a casing for an electronic device using the same will be described.
1. Base Steel Sheet The base steel sheet used in the coated steel sheet of the present invention is not particularly limited, and is generally a zinc-based plated steel sheet having a plating layer containing zinc, which is generally used in a coated steel sheet, that is, a galvanized steel sheet or a zinc alloy. A plated steel sheet or an alloyed plated steel sheet obtained by alloying these platings with a substrate may be used.
亜鉛系めっき鋼板は、電気めっき、溶融めっき、気相めっきのいずれで作製したものでもよい。亜鉛系めっき鋼板の例としては、溶融亜鉛めっき鋼板、電気亜鉛めっき鋼板、溶融5%Al−Zn合金めっき鋼板、溶融55%Al−Zn合金めっき鋼板、合金化溶融亜鉛めっき鋼板、電気Zn−Ni合金めっき鋼板などが挙げられる。ただし、後述するように熱放射率を高めるという観点から、合金化溶融亜鉛めっき鋼板とすることが好ましい。また、導電性を確保する観点からも、合金化溶融亜鉛めっき鋼板とすることが好ましい。 The zinc-based plated steel sheet may be produced by any of electroplating, hot dipping, and vapor phase plating. Examples of galvanized steel sheets include hot dip galvanized steel sheets, electrogalvanized steel sheets, molten 5% Al—Zn alloy plated steel sheets, molten 55% Al—Zn alloy plated steel sheets, alloyed hot dip galvanized steel sheets, electrical Zn—Ni. Examples include alloy plated steel sheets. However, from the viewpoint of increasing the thermal emissivity as described later, it is preferable to use an alloyed hot-dip galvanized steel sheet. Moreover, it is preferable to set it as an galvannealed steel plate also from a viewpoint of ensuring electroconductivity.
亜鉛系めっき鋼板のめっき付着量も特に限定されず、一般的な範囲内でよい。好ましくは、片面平均付着量で100g/m2以下である。この付着量は、より具体的には、電気めっきの場合には3g/m2以上50g/m2以下、溶融めっきの場合には30g/m2以上100g/m2以下とすることがより好ましい。
鋼板の厚さは、用途によって決定されるものではあるが、過度に厚い場合は加工性が低下することが懸念される。
The coating amount of the galvanized steel sheet is not particularly limited and may be within a general range. Preferably, the average adhesion amount on one side is 100 g / m 2 or less. More specifically, the adhesion amount is more preferably 3 g / m 2 or more and 50 g / m 2 or less in the case of electroplating, and 30 g / m 2 or more and 100 g / m 2 or less in the case of hot dipping. .
The thickness of the steel sheet is determined depending on the application, but if it is excessively thick, there is a concern that the workability is lowered.
2.塗装下地処理
塗装鋼板の製造では、塗膜密着性および耐食性を確保するため、塗装前に基材鋼板を前処理(塗装下地処理)するのが普通である。本発明に係る塗装鋼板も塗装下地処理としての化成処理を施し、塗膜厚の低下による一般的な意味での耐食性の低下を最小限に抑えることとしている。
2. Paint base treatment In the production of a coated steel sheet, it is common to pre-process the base steel sheet (paint base treatment) before coating in order to ensure adhesion and corrosion resistance of the coating film. The coated steel sheet according to the present invention is also subjected to a chemical conversion treatment as a coating ground treatment to minimize a decrease in corrosion resistance in a general sense due to a decrease in coating film thickness.
化成処理は、特に限定されないが、昨今の環境保護の観点から、クロムフリーの塗装鋼板とすることが好ましいため、クロメート処理ではなく、クロムを実質的に含有しない処理液を用いて行うことが好ましい。そのような化成処理液の代表例は、液相シリカ、気相シリカおよび/またはケイ酸塩などのケイ素化合物を主皮膜成分とし、場合により有機樹脂を共存させたシリカ系処理液である。 The chemical conversion treatment is not particularly limited, but from the viewpoint of environmental protection in recent years, it is preferable to use a chromium-free coated steel sheet, and therefore, it is preferable to use a treatment liquid that does not substantially contain chromium, not a chromate treatment. . A typical example of such a chemical conversion treatment liquid is a silica-based treatment liquid in which a silicon compound such as liquid phase silica, vapor phase silica and / or silicate is used as a main film component and optionally an organic resin is allowed to coexist.
化成処理は、シリカ系化成処理に限られるものではない。シリカ系以外にも、化成処理に使用するための各種のクロムフリー処理液が提案されており、また今後も提案されることが予想される。そのようなクロムフリー処理液を使用することもできる。形成される化成処理皮膜の付着量は、使用する化成処理に応じて、適当な付着量を選択すればよい。シリカ系化成処理液の場合、通常の付着量は、Si換算で1mg/m2以上20mg/m2以下の範囲内であろう。 The chemical conversion treatment is not limited to silica chemical conversion treatment. In addition to silica, various chromium-free treatment solutions for use in chemical conversion treatment have been proposed and are expected to be proposed in the future. Such a chromium-free processing solution can also be used. What is necessary is just to select the adhesion amount of the chemical conversion treatment film formed according to the chemical conversion treatment to be used. In the case of a silica-based chemical conversion treatment liquid, the normal adhesion amount will be in the range of 1 mg / m 2 or more and 20 mg / m 2 or less in terms of Si.
化成処理に先立って、Ni等の鉄族金属イオンを含む酸性もしくはアルカリ性水溶液による表面調整処理を施すことが多い。また、それ以前に、基材鋼板を清浄化するため、アルカリ脱脂などが通常は行われる。 Prior to the chemical conversion treatment, surface conditioning treatment with an acidic or alkaline aqueous solution containing an iron group metal ion such as Ni is often performed. Prior to that, alkaline degreasing or the like is usually performed to clean the base steel sheet.
3.おもて面
本発明に係る塗装鋼板は、その塗装鋼板を用いてなる筐体を有する製品においてその筐体の外側をなす面(以下、「おもて面」という。)に、上記の化成処理がなされ、その上に2層以上の塗膜からなる塗膜層を備える。この本発明に係る塗膜層の全体の厚さは10μm以下である。
3. Front surface The coated steel sheet according to the present invention has the above-mentioned chemical conversion formed on a surface (hereinafter referred to as “front surface”) that forms the outside of the housing in a product having a housing made of the coated steel plate. A treatment is performed, and a coating layer composed of two or more coating layers is provided thereon. The total thickness of the coating layer according to the present invention is 10 μm or less.
この2層以上の塗膜からなる塗膜層は、最外層をなす塗膜(最外層塗膜)と、最外層をなす塗膜以外の塗膜(下層塗膜)とに大別することができる。このうち、最外層塗膜は、塗料固形分に対して5質量%以上50質量%以下の着色顔料を含むとともに、膜厚が2μm以上かつ塗膜最表面のヤング率が5GPa以下である。 The coating layer composed of two or more coating layers can be broadly classified into a coating film forming the outermost layer (outermost layer coating film) and a coating film other than the coating film forming the outermost layer (lower layer coating film). it can. Among these, the outermost layer coating film contains a coloring pigment of 5% by mass or more and 50% by mass or less with respect to the solid content of the coating material, the film thickness is 2 μm or more, and the Young's modulus of the coating film outermost surface is 5 GPa or less.
一方、下層塗膜は、塗料固形分に対して5質量%以上30質量%以下の顔料を含むとともに膜厚が2μm以上である塗膜を備え、この塗膜に含有される顔料が、吸油量:100ml/100g以上1000ml/100g以下かつ比表面積:100m2/g以上1000m2/g以下を満たす防錆顔料としての多孔質シリカを、塗料固形分に対して5質量%以上30質量%以下含む。なお、下層塗膜は複数の塗膜から形成されていてもよく、その場合には、複数の塗膜からなる下層塗膜(層)の少なくとも一つが上記の構成を備えていればよい。 On the other hand, the lower layer coating film includes a coating film containing 5% by mass or more and 30% by mass or less of pigment with respect to the solid content of the coating material and has a film thickness of 2 μm or more. : 100 ml / 100 g or more and 1000 ml / 100 g or less and specific surface area: 100 m 2 / g or more and 1000 m 2 / g or less of porous silica as a rust preventive pigment is contained in an amount of 5% by mass to 30% by mass with respect to the solid content of the paint. . In addition, the lower layer coating film may be formed from a plurality of coating films, and in that case, at least one of the lower layer coating films (layers) composed of the plurality of coating films may have the above-described configuration.
ここで、「塗料固形分」とは塗料を焼き付けた際の固形分(塗膜)をいい、この「塗料」には塗装下地処理のための処理液は含まれない。塗料固形分の質量は次のようにして計測される。すなわち、所定量の塗料または塗料原料(主樹脂等)をオーブンに入れ、その質量を計測しながらオーブン内を加熱して塗料または塗料原料を固化させる。オーブン内の質量変化がなくなるまで固化させたときの固化物の質量計測値を塗料固形分の質量と定義する。したがって、「塗料固形分に対する質量%」とは、この重量計測値を100%としたときの質量割合をいう。 Here, the “paint solid content” refers to a solid content (coating film) when the paint is baked, and this “paint” does not include a treatment liquid for coating base treatment. The mass of the paint solids is measured as follows. That is, a predetermined amount of paint or paint raw material (main resin or the like) is placed in an oven, and the inside of the oven is heated while measuring its mass to solidify the paint or paint raw material. The mass measurement value of the solidified product when solidified until there is no mass change in the oven is defined as the mass of the solid content of the paint. Therefore, “mass% with respect to the solid content of the paint” refers to a mass ratio when the weight measurement value is 100%.
(1)最外層塗膜
まず、最外層塗膜について詳しく説明する。
A)バインダー成分
最外層塗膜を構成するバインダー成分は、バインダーの主成分であるバインダー樹脂、硬化剤、およびその他の成分から構成され、最外層塗装が後述する最表面のヤング率を実現できるのであれば、これらの種類は特に限定されない。バインダー樹脂としては、例えば、ポリエステル樹脂、アクリル樹脂、エポキシ樹脂、ポリウレタン樹脂、シリコーンポリエステル樹脂、ポリ塩化ビニル樹脂、フッ素樹脂などから選んだ1種または2種以上を使用することができる。また、硬化剤はメラミン樹脂、ポリイソシアネート化合物などが 例示され、架橋触媒の配合の可否を含め、目的に合わせて適宜設定すればよい。最表面のヤング率を後述するように5GPa以下とする観点からは、バインダー樹脂のTgはポリエステル樹脂では、10℃以上40℃以下の範囲とすることが好ましい。
(1) Outermost layer coating film First, the outermost layer coating film will be described in detail.
A) Binder component The binder component constituting the outermost layer coating film is composed of a binder resin, a curing agent, and other components, which are the main components of the binder, and the outermost layer coating can realize the Young's modulus of the outermost surface described later. If there are, these types are not particularly limited. As the binder resin, for example, one or more selected from polyester resins, acrylic resins, epoxy resins, polyurethane resins, silicone polyester resins, polyvinyl chloride resins, fluororesins, and the like can be used. Further, examples of the curing agent include melamine resin and polyisocyanate compound, and the curing agent may be appropriately set according to the purpose, including whether or not a crosslinking catalyst is blended. From the viewpoint of setting the Young's modulus of the outermost surface to 5 GPa or less as described later, the Tg of the binder resin is preferably in the range of 10 ° C. or more and 40 ° C. or less for the polyester resin.
バインダー成分の含有量は、塗料固形分に対して40質量%以上95質量%以下とすることが好ましい。バインダー成分の含有量が過度に多い場合には相対的に顔料の含有量が低下し、耐食性が低下したりする。一方、その含有量が過度に低い場合には、塗膜強度が低下して、耐疵付き性が低下したり、加工性が低下したり、所望の色調の着色が困難になったりする。特に好ましい含有量の範囲は、塗料固形分に対して50質量%以上90質量%以下である。 The content of the binder component is preferably 40% by mass to 95% by mass with respect to the solid content of the paint. When the content of the binder component is excessively large, the content of the pigment is relatively lowered and the corrosion resistance is lowered. On the other hand, when the content is excessively low, the strength of the coating film is lowered, the scratch resistance is lowered, the workability is lowered, or the coloring of a desired color tone is difficult. A particularly preferable range of the content is 50% by mass or more and 90% by mass or less based on the solid content of the paint.
B)顔料成分
「顔料」とは防錆や着色などを目的とした顔料全体をいい、本発明に係る最外層塗膜では顔料のうち着色顔料を含有する。その具体的な種類は特に限定されない。酸化亜鉛、酸化チタン、炭酸カルシウム、カオリンなどの無機顔料、銅フタロシアニン、トルイジンレッドなどの有機顔料、さらにはカーボンブラックなど所望の色調に合わせて適宜使用すればよい。また、所定の意匠を満足するために、着色顔料の一部または全部としてアルミフレーク、マイカ等の光輝顔料を必要に応じ用いてもよい。
B) Pigment component “Pigment” refers to the entire pigment for the purpose of rust prevention and coloring, and the outermost coating film according to the present invention contains a colored pigment among the pigments. The specific type is not particularly limited. What is necessary is just to use suitably according to desired color tone, such as inorganic pigments, such as a zinc oxide, a titanium oxide, a calcium carbonate, a kaolin, organic pigments, such as copper phthalocyanine and toluidine red, and also carbon black. Further, in order to satisfy a predetermined design, bright pigments such as aluminum flakes and mica may be used as necessary as part or all of the colored pigments.
着色顔料の含有量を、塗料固形分に対して5質量%以上50質量%以下とする。この範囲を外れて含有量が過度に少ない場合には所定の色調を安定的に発現させることが困難となり、過度に多い場合には塗膜強度が低下したり、平面部耐食性が著しく低下したりする。 The content of the color pigment is set to 5% by mass or more and 50% by mass or less based on the solid content of the paint. If the content is too small outside this range, it will be difficult to stably develop a predetermined color tone, and if it is too large, the coating film strength may be reduced, or the flat surface corrosion resistance may be significantly reduced. To do.
最外層塗膜は着色顔料以外に防錆顔料を含有してもよい。防錆顔料の例としては、トリポリリン酸アルミニウム、リン酸および亜リン酸のZn、Mg、Al、Ti、Zr、およびCe塩、Caイオン交換シリカ、ならびに吸油量100ml/100g以上1000ml/100g以下かつ比表面積100m2/g以上1000m2/g以下を満たす多孔質シリカ粒子(以下「多孔質シリカ顔料」と略記する。)が挙げられる。防錆顔料をも含有させる場合であっても、防錆顔料と着色顔料とを含む顔料全体の含有量を塗料固形分に対して5質量%以上50質量%以下とすることが特に好ましい。 The outermost layer coating film may contain a rust preventive pigment in addition to the color pigment. Examples of the antirust pigment include aluminum tripolyphosphate, phosphoric acid and phosphorous acid Zn, Mg, Al, Ti, Zr, and Ce salts, Ca ion exchange silica, and oil absorption of 100 ml / 100 g to 1000 ml / 100 g and Examples thereof include porous silica particles satisfying a specific surface area of 100 m 2 / g or more and 1000 m 2 / g or less (hereinafter abbreviated as “porous silica pigment”). Even when the rust preventive pigment is contained, it is particularly preferable that the content of the entire pigment including the rust preventive pigment and the color pigment is 5% by mass or more and 50% by mass or less based on the solid content of the paint.
上記の多孔質シリカ顔料の吸油量および比表面積の範囲について、吸油量100ml/100g未満または比表面積100m2/g未満の場合には十分な耐食性能を得ることが困難となってしまう。逆に、吸油量1000ml/100gを超えたり比表面積1000m2/gを超えたりする場合には、塗料中に添加した際の塗料安定性、塗装性を損なうため適していない。 When the oil absorption amount and the specific surface area of the porous silica pigment are less than 100 ml / 100 g or less than 100 m 2 / g, it is difficult to obtain sufficient corrosion resistance. Conversely, if the oil absorption exceeds 1000 ml / 100 g or exceeds a specific surface area of 1000 m 2 / g, it is not suitable because it impairs the stability and paintability of the paint when added to the paint.
顔料の形状は特に限定されないが、形状が過剰に大きい場合(具体例として顔料の平均一次粒径が本発明に係る塗膜層全体の厚さの最大値である10μmよりもはるかに大きい場合が挙げられる。)には、塗布工程において不都合を生じる可能性が高まる。例えば、ロールコーターを用いて塗布する場合には、顔料の形状が過剰に大きいとロールギャップを通過することが困難となり、調製時の塗料における顔料の含有量と塗布された塗料における顔料の含有量とが大きく異なってしまう。その結果、塗膜が所定の特性を得られなくなることが懸念される。また、顔料の形状が過剰に大きい場合には、乾燥により得られた塗膜層の厚さが不均一になるとともに、二次加工においてワレの起点となったりすることが懸念される。したがって、顔料の形状は、平均一次粒径として塗膜層全体の厚さの2倍以内であることが好ましい。また、最外層塗膜の塗布工程を安定的に行うという観点からは、顔料の平均一次粒径が最外層塗膜の厚さの3倍以内であることが好ましく、1倍以内であれば特に好ましい。 The shape of the pigment is not particularly limited, but when the shape is excessively large (as a specific example, the average primary particle size of the pigment may be much larger than 10 μm which is the maximum value of the entire thickness of the coating layer according to the present invention). The possibility of causing inconveniences in the coating process is increased. For example, when applying using a roll coater, if the shape of the pigment is excessively large, it becomes difficult to pass through the roll gap, and the pigment content in the paint at the time of preparation and the pigment content in the applied paint And will be very different. As a result, there is a concern that the coating film cannot obtain predetermined characteristics. Moreover, when the shape of the pigment is excessively large, the thickness of the coating layer obtained by drying is not uniform, and there is a concern that cracking may occur in the secondary processing. Accordingly, the shape of the pigment is preferably within twice the thickness of the entire coating layer as the average primary particle size. Further, from the viewpoint of stably performing the coating process of the outermost layer coating film, the average primary particle diameter of the pigment is preferably within 3 times the thickness of the outermost layer coating film, and particularly within 1 times preferable.
なお、「平均一次粒径」は、その測定方法によりある程度変動するが、いずれの方法を用いても、塗膜層からの顔料の脱落を防止して安定した塗装性および良好な塗膜加工性を実現する観点からは塗膜層全体の厚さの約2倍以内とすることが好ましく、生産の安定性の観点からは最外層塗膜の厚さの約3倍以内とすることが好ましいという基本的傾向は変わらない。 The “average primary particle size” varies to some extent depending on the measurement method, but any method can be used to prevent the pigment from falling off the coating layer and to provide stable coating properties and good coating film processability. From the viewpoint of realizing the above, it is preferable to be within about twice the thickness of the entire coating layer, and from the viewpoint of production stability, it is preferable to be within about three times the thickness of the outermost coating layer. The basic trend remains the same.
ここで、本発明に係る塗装鋼板を屋外用途等で用いる場合には、切断端面からの赤錆の発生を抑制するために、下記(i)および(ii)の要件を満たす少なくとも1種の非クロム化合物を含有してもよい。 Here, when the coated steel sheet according to the present invention is used for outdoor use or the like, in order to suppress the occurrence of red rust from the cut end face, at least one kind of non-chrome that satisfies the following requirements (i) and (ii): A compound may be contained.
(i)イオン交換水(電気伝導度:4μS/cm以下)に0.1質量%濃度で溶解させた時の水の電気伝導度が500μS/cm以上、
(ii)200℃までに熱分解を生じない。
(i) The electric conductivity of water when dissolved in ion exchange water (electric conductivity: 4 μS / cm or less) at a concentration of 0.1% by mass is 500 μS / cm or more,
(ii) No thermal decomposition occurs up to 200 ° C.
非クロム化合物については、アルカリ金属リン酸塩が好ましく、リン酸二水素カリウムや、リン酸水素二カリウム、トリポリリン酸ナトリウム等が例示される。
上記赤錆抑制添加化合物の添加量としては、塗料固形分に対して、1質量%以上10質量%以下含有することが好ましい。
As for the non-chromium compound, an alkali metal phosphate is preferable, and examples thereof include potassium dihydrogen phosphate, dipotassium hydrogen phosphate, and sodium tripolyphosphate.
The addition amount of the red rust inhibiting additive compound is preferably 1% by mass or more and 10% by mass or less based on the solid content of the paint.
C)その他の成分
最外層塗膜中に含まれる成分としては、上記のバインダー成分および顔料以外に、レベリング剤、外観の凹凸やプレス性の向上を得るためのアクリルビーズやPTFE等の樹脂ビーズ、溶接性や電磁波シールド性を向上させるための導電粉、潤滑性を向上させるためのワックス等が挙げられ、これらを必要に応じて適宜含有させてもよい。
C) Other components In addition to the binder component and pigment described above, the components contained in the outermost layer coating film include leveling agents, resin beads such as acrylic beads and PTFE for improving the appearance irregularities and pressability, Examples thereof include conductive powder for improving weldability and electromagnetic wave shielding properties, wax for improving lubricity, and the like, which may be appropriately contained as necessary.
但し、これらの成分の含有量が増えすぎると加工性が低下することが懸念されるため、これらの合計含有量は塗料固形分に対して30質量%以下とすることが好ましく、20質量%以下とすることが特に好ましい。 However, since it is feared that the processability is lowered when the content of these components is excessively increased, the total content thereof is preferably 30% by mass or less, and 20% by mass or less with respect to the solid content of the paint. It is particularly preferable that
D)膜厚
最外層塗膜の厚さを2μm以上とする。後述するように下層塗膜が防錆機能に特に優れた防錆顔料を含むため、最外層塗膜の膜厚が2μmあれば実用の範囲で十分な平面部耐食性を有しつつ、塗膜層としての色調が安定した塗膜を得ることが実現される。具体的には、2μm未満では塗膜層の色調が下層塗膜の色調の影響を受けやすく、例えば工程上の理由により下層塗膜の膜厚が変動したときに、その変動に起因する下層塗膜の色調の変動がそのまま塗膜層の色調の変動として現れやすくなる。
D) Film thickness The thickness of the outermost coating film is 2 μm or more. As will be described later, since the lower layer coating film contains a rust preventive pigment that is particularly excellent in rust prevention function, the coating layer has sufficient flat surface corrosion resistance within a practical range if the thickness of the outermost layer coating film is 2 μm. It is realized to obtain a coating film having a stable color tone. Specifically, if it is less than 2 μm, the color tone of the coating film layer is easily affected by the color tone of the lower layer coating film. For example, when the film thickness of the lower layer coating film changes due to a process reason, Variations in the color tone of the film tend to appear as variations in the color tone of the coating layer.
色調の安定性を高度に実現する観点からは最外層塗膜の厚さを3μm以上とすることが好ましい。この場合には、例えば工程上の理由により最外層塗膜の膜厚に変動が発生して仮に膜厚が1μm減少したとしても、最外層塗膜の膜厚は2μmを確保することができるため、下層塗膜の色調の影響が塗膜層の色調に現れにくい。したがって、最外層塗膜の膜厚の変動に起因する塗膜層の色調の変動が特に生じにくい。 From the viewpoint of highly realizing the stability of the color tone, the thickness of the outermost layer coating film is preferably 3 μm or more. In this case, for example, even if the film thickness of the outermost layer coating film fluctuates due to process reasons and the film thickness is reduced by 1 μm, the outermost layer coating film thickness of 2 μm can be secured. The influence of the color tone of the lower layer coating film hardly appears in the color tone of the coating layer. Therefore, the color tone of the coating film layer is hardly changed due to the change in the film thickness of the outermost layer coating film.
一方、最外層塗膜および下層塗膜の合計塗膜厚さが10μm以下であって、後述するように下層塗膜の最小膜厚が2μmであるから、最外層塗膜の上限は8μmとなる。色調の安定性の観点から、最外層塗膜の膜厚が下層塗膜の膜厚以上であることが好ましい。 On the other hand, since the total coating thickness of the outermost layer coating film and the lower layer coating film is 10 μm or less and the minimum film thickness of the lower layer coating film is 2 μm as will be described later, the upper limit of the outermost layer coating film is 8 μm. . From the viewpoint of color stability, it is preferable that the film thickness of the outermost layer coating film is equal to or greater than the film thickness of the lower layer coating film.
E)ヤング率
最外層塗膜の最表面のヤング率は5GPa以下とする。最表面のヤング率が5GPaを超えると、塗膜表面の硬度が高いため加工性が低下してしまう。好ましいヤング率の範囲は0.3GPa以上5GPa以下であり、0.5GPa以上2GPa以下であれば特に好ましい。
E) Young's modulus The Young's modulus of the outermost surface of the outermost layer coating film is 5 GPa or less. When the Young's modulus of the outermost surface exceeds 5 GPa, the workability deteriorates because the hardness of the coating film surface is high. The range of the preferred Young's modulus is 0.3 GPa or more and 5 GPa or less, and particularly preferably 0.5 GPa or more and 2 GPa or less.
なお、最外層塗膜の最表面のヤング率の測定方法は次のようにして行う。
市販の表面皮膜物性試験機(例えば(株)フィッシャー・インストルメンツ社製フィッシャースコープHM−2000)を用い、シャーリングなど任意の方法で切断された20mm×20mmの塗装サンプルを、試験機の測定ステージ上に塗装面を上にして設置する。
In addition, the measuring method of the Young's modulus of the outermost surface of an outermost layer coating film is performed as follows.
Using a commercially available surface film property testing machine (for example, Fisherscope HM-2000 manufactured by Fisher Instruments Co., Ltd.), a 20 mm × 20 mm coated sample cut by any method such as shearing is placed on the measurement stage of the testing machine. Install with the paint side facing up.
この固定された塗装サンプルに対して、四角錐からなるビッカース圧子を、押し込み最大荷重を2mN、荷重付加時のアプリケーション時間を20s、クリープ時間を5s、荷重減少時のアプリケーション時間を20s、荷重除去後のクリープ時間を5sとして押し込む。なお、測定温度は室温とする。 A Vickers indenter consisting of a quadrangular pyramid is pressed against this fixed coating sample, the maximum load is 2 mN, the application time when a load is applied is 20 s, the creep time is 5 s, the application time when the load is reduced is 20 s, after the load is removed Push in with a creep time of 5s. The measurement temperature is room temperature.
各塗装サンプルにつき30点ずつ圧子を押し込んでヤング率の測定を行い、得られた結果のうち、最大値から数値の大きい順に5点、最小値から数値の小さい順に5点を取り除き、残り20点の平均値を塗膜最表面のヤング率とする。 Measure the Young's modulus by pushing indenters 30 points for each paint sample, and remove 5 points from the maximum value in descending order of numerical values, 5 points from the minimum value in ascending order of numerical values, and the remaining 20 points. Is the Young's modulus of the outermost surface of the coating film.
F)製造方法
最外層塗膜の製造方法は特に限定されない。常法にしたがって、上記の構成成分を適切な媒体に溶解および/または分散させて塗膜形成用液状組成物とし、後述する下層塗膜の上に任意の方法でこの組成物を所定の厚さで塗布し、加熱などを行って媒体を揮発させるとともにバインダー成分を硬化させて、固体の塗膜とすればよい。
F) Manufacturing method The manufacturing method of an outermost layer coating film is not specifically limited. According to a conventional method, the above-described constituent components are dissolved and / or dispersed in an appropriate medium to form a liquid composition for forming a coating film. It is sufficient to apply the coating and heat to volatilize the medium and cure the binder component to form a solid coating.
(2)下層塗膜
続いて、下層塗膜について詳しく説明する。下層塗膜は、鋼板の化成処理がなされた面上に形成される塗膜層のうち、最外層をなす塗膜以外の層を意味する。したがって、下層塗膜は、一層である場合もあれば、二層以上である場合もある。以下の説明では、各項目において、一層である場合を先に説明し二層以上の場合について適宜続いて説明する。
(2) Lower layer coating film Subsequently, the lower layer coating film will be described in detail. A lower layer coating film means layers other than the coating film which makes the outermost layer among the coating film layers formed on the surface where the chemical conversion treatment of the steel plate was made. Therefore, the lower layer coating film may be a single layer or may be two or more layers. In the following description, in each item, the case of one layer will be described first, and the case of two or more layers will be described as appropriate.
A)バインダー成分
下層塗膜を構成するバインダー成分も、バインダーの主成分であるバインダー樹脂、硬化剤、およびその他の成分から構成され、これらの種類は特に限定されないが、耐食性と加工性とを両立する観点からは、ポリエステル樹脂、エポキシ樹脂、ポリウレタン樹脂からなる1種または2種以上のバインダー樹脂に硬化剤として、メラミン樹脂、ポリイソシアネート化合物を含む系が好ましい。下層塗膜が複数の塗膜から構成される場合には、各塗膜のバインダー成分は相違していてもよいし一部または全部が同一であってもよい。各塗膜間での密着性を確保する観点からは同一成分であることが好ましい。
A) Binder component The binder component that constitutes the lower layer coating film is also composed of a binder resin, a curing agent, and other components, which are the main components of the binder, and these types are not particularly limited, but both corrosion resistance and workability are compatible. From this viewpoint, a system containing a melamine resin and a polyisocyanate compound as a curing agent in one or more binder resins made of a polyester resin, an epoxy resin, and a polyurethane resin is preferable. When a lower layer coating film is comprised from several coating films, the binder component of each coating film may differ, and one part or all part may be the same. From the viewpoint of ensuring adhesion between the coating films, the same component is preferred.
B)顔料成分
本発明では、下層塗膜に含有される顔料は、塗料固形分に対して5質量%以上30質量%以下の顔料を含むとともに、吸油量:100ml/100g以上1000ml/100g以下、かつ比表面積:100m2/g以上1000m2/g以下を満たす多孔質シリカ粒子からなる多孔質シリカ顔料を防錆顔料として含む。かかる多孔質シリカ顔料を含む下層塗膜は平面部耐食性に特に優れるため、下層塗膜の厚さを2μm程度とすることができる。
B) Pigment component In the present invention, the pigment contained in the lower layer coating film contains 5% by mass or more and 30% by mass or less of pigment with respect to the solid content of the paint, and the oil absorption: 100 ml / 100 g or more and 1000 ml / 100 g or less, In addition, a porous silica pigment composed of porous silica particles satisfying a specific surface area of 100 m 2 / g or more and 1000 m 2 / g or less is included as a rust preventive pigment. Since the lower layer coating film containing such a porous silica pigment is particularly excellent in the corrosion resistance of the flat portion, the thickness of the lower layer coating film can be about 2 μm.
上記の多孔質シリカ顔料の吸油量、比表面積の範囲が好ましい理由は最外層塗膜に添加された場合と同じである。
また、多孔質シリカ顔料の形状についての好適範囲についても、最外層塗膜に含有される顔料の場合と同様に、多孔質シリカ顔料の平均一次粒径は、塗膜層全体の厚さの2倍以内および多孔質シリカ顔料が含まれる下層塗膜の厚さの3倍以内の少なくとも一方を満たすことが好ましく、両方を満たすことがより好ましい。下層塗膜が複数の層から形成される場合には、各塗膜について、多孔質シリカ顔料の平均一次粒径が塗膜厚さの3倍以内であることが好ましい。
The reason why the range of the oil absorption amount and the specific surface area of the porous silica pigment is preferable is the same as that when added to the outermost layer coating film.
Moreover, also about the suitable range about the shape of a porous silica pigment, the average primary particle diameter of a porous silica pigment is 2 of the thickness of the whole coating layer similarly to the case of the pigment contained in an outermost layer coating film. It is preferable to satisfy at least one of within 3 times and within 3 times the thickness of the lower layer coating film containing the porous silica pigment, and it is more preferable to satisfy both. When the lower layer coating film is formed from a plurality of layers, the average primary particle diameter of the porous silica pigment is preferably within 3 times the coating film thickness for each coating film.
この多孔質シリカ顔料の含有量を塗料固形分に対して5質量%以上30質量%以下とする。含有量が5質量%未満の場合には、下層塗膜の厚さを2μmとしたときに十分な平面部耐食性を実現することが困難となってしまう。一方、含有量が30質量%を超える場合には、加工性が低下し、成形したときに塗膜にクラックが発生しやすくなってしまう。 The content of the porous silica pigment is set to 5% by mass or more and 30% by mass or less with respect to the solid content of the paint. When the content is less than 5% by mass, it becomes difficult to realize sufficient planar portion corrosion resistance when the thickness of the lower layer coating film is 2 μm. On the other hand, when the content exceeds 30% by mass, workability is lowered, and cracks are likely to occur in the coating film when it is molded.
ここで、この多孔質シリカ顔料以外に、他の防錆顔料、例えばトリポリリン酸アルミニウムやカルシウム交換シリカを含有してもかまわない。ただし、平面部耐食性を確保する観点から多孔質シリカ顔料の含有量を塗料固形分に対して5質量%以上とするとともに、加工性を維持する観点から多孔質シリカ顔料と他の防錆顔料との合計含有量を塗料固形分に対して30質量%以下とする。 Here, in addition to the porous silica pigment, other rust preventive pigments such as aluminum tripolyphosphate and calcium exchange silica may be contained. However, the content of the porous silica pigment is set to 5% by mass or more based on the solid content of the paint from the viewpoint of ensuring the corrosion resistance of the flat portion, and the porous silica pigment and other rust preventive pigments from the viewpoint of maintaining the workability. The total content of is 30% by mass or less based on the solid content of the paint.
また、防錆顔料以外の顔料、具体例を挙げれば、チタニアおよびカーボンブラックから選ばれる一種または二種からなる着色顔料を含有させてもよい。このようにすることで、下層塗膜にも素地鋼板に対する隠蔽性が付与される。このため、塗膜全体としての色調の安定性がさらに高まり、好ましい。 In addition, pigments other than the rust preventive pigment, and specific examples may include one or two color pigments selected from titania and carbon black. By doing in this way, the concealability with respect to a base steel plate is provided also to a lower layer coating film. For this reason, the stability of the color tone as the whole coating film further increases, which is preferable.
ただし、着色顔料を含有させることによって、上記の多孔質シリカ顔料のバインダー成分と顔料成分との合計に対する含有量が相対的に低下して平面部耐食性が低下することは避けるべきである。したがって、多孔質シリカ顔料の含有量は、着色顔料を含有させない場合と同様に、塗料固形分に対して5質量%以上30質量%以下の範囲を維持しつつ、着色顔料の含有量は、多孔質シリカを含む他の顔料との合計含有量として、塗料固形分に対して30質量%以下とする。この含有量を維持していれば、着色顔料などを含有させる場合であっても下層塗膜の最低膜厚を下記のように2μmとすることが実現される。 However, it should be avoided that the content of the above-mentioned porous silica pigment relative to the total of the binder component and the pigment component is relatively decreased and the planar portion corrosion resistance is decreased due to the inclusion of the color pigment. Accordingly, the content of the porous silica pigment is maintained in the range of 5% by mass or more and 30% by mass or less with respect to the solid content of the paint as in the case where the color pigment is not contained, and the content of the color pigment is porous. The total content with other pigments containing porous silica is 30% by mass or less based on the solid content of the paint. If this content is maintained, even when a coloring pigment or the like is contained, it is realized that the minimum film thickness of the lower layer coating film is 2 μm as described below.
下層塗膜が、二層以上の塗膜から構成される場合には、下層塗膜を構成する塗膜のうち一層のみが多孔質シリカ顔料を5質量%以上30質量%以下の含有量で含んでもよいが、全ての塗膜が個別に多孔質シリカ顔料を上記の含有量で含むことが好ましい。 When the lower coating film is composed of two or more coating films, only one of the coating films constituting the lower coating film contains the porous silica pigment in a content of 5% by mass or more and 30% by mass or less. However, it is preferable that all the coating films individually contain the porous silica pigment in the above content.
C)その他の成分
下層塗膜についても、最外層塗膜と同様にバインダー成分および顔料成分以外の成分を含有させてもよいが、平面部耐食性確保の観点から、その他の成分の合計含有量は塗料固形分に対して10質量%以下とすることが好ましく、5質量%以下とすることが特に好ましい。
C) Other components Although the lower layer coating film may contain components other than the binder component and the pigment component in the same manner as the outermost layer coating film, the total content of the other components is from the viewpoint of ensuring the corrosion resistance of the plane portion. It is preferable to set it as 10 mass% or less with respect to coating-material solid content, and it is especially preferable to set it as 5 mass% or less.
D)膜厚
上記のように、10μmを膜厚の上限値とする塗膜層のうち最外層塗膜以外のものが「下層塗膜」であり、最外層塗膜の厚さは2μm以上であるから、下層塗膜が一層からなる場合にはその膜厚の上限値は8μmである。一方、この場合における下層塗膜の厚さの下限値は2μmである。下層塗膜の厚さを2μm未満とすると、所望の平面部耐食性を得ることが困難となる。
D) Thickness As described above, the coating layer other than the outermost coating layer among the coating layers having an upper limit of 10 μm is the “lower coating layer”, and the thickness of the outermost coating layer is 2 μm or more. Therefore, when the lower coating film is composed of one layer, the upper limit value of the film thickness is 8 μm. On the other hand, the lower limit of the thickness of the lower layer coating film in this case is 2 μm. When the thickness of the lower layer coating film is less than 2 μm, it becomes difficult to obtain desired plane portion corrosion resistance.
下層塗膜が二層以上の塗膜から構成される場合には、下層塗膜全体の厚さの上限値が8μmとなる。したがって、下層塗膜を構成する塗膜の個別の膜厚は8μm未満となる。一方、下層塗膜を構成する塗膜の厚さの下限については、下層塗膜を構成する塗膜のうち、多孔質シリカ顔料を5質量%以上30質量%以下の含有量で含む塗膜の少なくとも一つが2μm以上である。この塗膜の厚さを2μm未満とすると、所望の平面部耐食性を得ることが困難となる。なお、多孔質シリカ顔料を5質量%以上30質量%以下の含有量で含む塗膜が複数あり、これらが連続して積層されているときには、それらの塗膜の累積膜厚が2μm以上であればよい。 When the lower layer coating film is composed of two or more layers, the upper limit value of the thickness of the entire lower layer coating film is 8 μm. Therefore, the individual film thickness of the coating film constituting the lower layer coating film is less than 8 μm. On the other hand, about the minimum of the thickness of the coating film which comprises a lower layer coating film, among the coating films which comprise a lower layer coating film, the coating film which contains a porous silica pigment by 5 to 30 mass% content At least one is 2 μm or more. When the thickness of this coating film is less than 2 μm, it becomes difficult to obtain desired flat surface corrosion resistance. In addition, when there are a plurality of coating films containing a porous silica pigment in a content of 5% by mass or more and 30% by mass or less, and these are continuously laminated, the cumulative film thickness of those coatings should be 2 μm or more. That's fine.
E)製造方法
塗装塗膜の製造方法も特に限定されない。最外層塗膜の場合と同様に、適切な媒体に溶解および/または分散させて塗膜形成用液状組成物とし、適切な方法で素地鋼板上にこれを所定の厚さで塗布し、加熱などを適宜行って塗膜とすればよい。なお、上記の多孔質シリカ顔料を分散させやすくする観点からは、分散剤を添加することが好ましい。
E) Manufacturing method The manufacturing method of a coating film is not specifically limited, either. As in the case of the outermost layer coating film, it is dissolved and / or dispersed in an appropriate medium to form a liquid composition for coating film formation, and this is applied to the base steel sheet by a suitable method at a predetermined thickness, and heated. Is appropriately performed to form a coating film. In addition, it is preferable to add a dispersing agent from a viewpoint of making it easy to disperse | distribute said porous silica pigment.
4.裏面
本発明に係る塗装鋼板は、その塗装鋼板を用いてなる筐体を有する製品においてその筐体の内側をなす面(以下、「裏面」という。)における塗膜については、特に限定されない。上記のおもて面に形成された塗膜層を備えていてもよいし、この塗膜層とは異なる塗膜が形成されていてもよい。
4). Back surface The coated steel plate according to the present invention is not particularly limited with respect to the coating film on the surface (hereinafter referred to as “back surface”) that forms the inside of the housing in a product having a housing made of the coated steel plate. The coating layer formed in the said front surface may be provided, and the coating film different from this coating layer may be formed.
ただし、本発明に係る塗装鋼板が電子機器用の筐体に適用される場合には、裏面が所定の物理特性を有していることが好ましく、この物理特性を実現する観点から特定の被覆層を備えることが好ましい。以下にこれらの点について説明する。 However, when the coated steel sheet according to the present invention is applied to a housing for an electronic device, the back surface preferably has a predetermined physical property, and a specific coating layer is provided from the viewpoint of realizing this physical property. It is preferable to provide. These points will be described below.
(1)熱放射率
本発明に係る塗装鋼板の裏面からの熱放射率が40%以上であることが好ましい。このような高い熱放射率を有することで、電子機器内部から生じた熱を吸収(吸熱)する効率が高まり、電子機器の筐体として適用した場合に電子機器内部の部品の不具合発生率を低下させることが可能となる。
(1) Thermal emissivity It is preferable that the thermal emissivity from the back surface of the coated steel plate according to the present invention is 40% or more. By having such a high thermal emissivity, the efficiency of absorbing (absorbing heat) generated from the inside of the electronic device is increased, and the failure occurrence rate of components inside the electronic device is reduced when applied as a casing of the electronic device. It becomes possible to make it.
(2)被覆層
うら面には、無機被覆および無機有機複合被覆から選ばれる一種または二種を1層以上有する被覆層が設けられていることが好ましい。
このような被覆層を有することで、耐食性および導電性が実現される。
(2) Coating layer It is preferable that the back surface is provided with a coating layer having at least one kind selected from inorganic coating and inorganic-organic composite coating.
By having such a coating layer, corrosion resistance and electrical conductivity are realized.
無機被覆としては、クロメート処理や、リン酸塩系の処理、シリコンおよびシリケートを含む処理等をいい、「無機有機複合被覆」とは、前記の無機被覆において水溶性フェノール樹脂などの有機樹脂を配合させた処理をいう。環境保護の観点からは、Crを含まない化合物が好ましく、Si、P、V、Al、Mg、Mo、ZrおよびTiから選ばれる1種以上の元素を含む化合物が例示される。 Inorganic coating refers to chromate treatment, phosphate treatment, treatment containing silicon and silicate, etc. "Inorganic organic composite coating" refers to organic coating such as water-soluble phenolic resin in the inorganic coating. Refers to the processing that was performed. From the viewpoint of environmental protection, a compound containing no Cr is preferable, and examples include compounds containing one or more elements selected from Si, P, V, Al, Mg, Mo, Zr and Ti.
被覆層の付着量は、10mg/m2以上1000mg/m2以下とすることが好ましい。付着量が10mg/m2未満の場合には耐食性や耐疵付き性が低下することが懸念される。一方、付着量が1000mg/m2超の場合には加工性が低下したり次に説明する表面抵抗が高くなりすぎたりすることが懸念される。 The adhesion amount of the coating layer is preferably 10 mg / m 2 or more and 1000 mg / m 2 or less. When the amount of adhesion is less than 10 mg / m 2 , there is a concern that the corrosion resistance and wrinkle resistance will decrease. On the other hand, when the adhesion amount is more than 1000 mg / m 2 , there is a concern that the workability is lowered or the surface resistance described below becomes too high.
被覆層の付着方法は特に限定されず、被覆層を構成する無機材料および/もしくは有機無機複合材料ならびに/またはそれらの前駆体を適切な媒体に溶解および/または分散させて被覆層形成用液状組成物とし、これを公知の手法で素地鋼板の裏面に塗布し、加熱などを適宜行って媒体を揮発させるとともに無機材料および/または有機無機複合材料からなる被覆層へと硬化させればよい。 The method for attaching the coating layer is not particularly limited, and a liquid composition for forming the coating layer is prepared by dissolving and / or dispersing the inorganic material and / or the organic-inorganic composite material and / or their precursors constituting the coating layer in an appropriate medium. This may be applied to the back surface of the base steel plate by a known method, and the medium may be volatilized appropriately by heating or the like and cured to a coating layer made of an inorganic material and / or an organic-inorganic composite material.
(3)表面抵抗
本発明に係る塗装鋼板の裏面の表面抵抗値は5Ω以下であることが好ましい。このような低い表面抵抗値を有することで、電子機器の筐体として適用した場合に、その機器を設置することにより電子機器内部の部品の不具合発生率を低下させることが可能となる。
(3) Surface resistance It is preferable that the surface resistance value of the back surface of the coated steel plate which concerns on this invention is 5 ohms or less. By having such a low surface resistance value, when it is applied as a casing of an electronic device, it is possible to reduce the defect occurrence rate of components inside the electronic device by installing the device.
5.成形
本発明の塗装鋼板から、例えば、打ち抜き、プレス成形といった慣用の方法により製品において筐体をなす部材を形成することができる。この筐体は塗膜厚が10μm以下と薄いにもかかわらず平面部耐食性に優れているので、電子機器、例えば液晶テレビ、有機ELテレビ、プラズマテレビのような薄型テレビ用パネルで代表されるAV機器の筐体(ハウジング)として使用されることが好ましい。
5). Forming From the coated steel sheet of the present invention, for example, a member forming a casing in a product can be formed by a conventional method such as punching or press forming. This casing has excellent flat surface corrosion resistance despite its thin coating thickness of 10 μm or less. Therefore, AV equipment typified by thin panels for electronic devices such as liquid crystal televisions, organic EL televisions, and plasma televisions. It is preferable to be used as a housing (housing) for equipment.
(実施例1)
溶融亜鉛めっき鋼板(片面亜鉛付着量:45g/m2)に対して、市販の化成処理液(日本ペイント社製EC2330)をSi換算で5mg/m2となるように塗布し、板の到達温度が10秒で80℃になるように塗布後の鋼板を加熱し、おもて面の化成処理皮膜を形成した。
Example 1
A commercially available chemical conversion liquid (EC2330 manufactured by Nippon Paint Co., Ltd.) was applied to a hot-dip galvanized steel sheet (single-side zinc adhesion amount: 45 g / m 2 ) so as to be 5 mg / m 2 in terms of Si. Was heated to 80 ° C. in 10 seconds to form a chemical conversion coating on the front surface.
ベース塗料:主樹脂として、ポリエステル樹脂のバイロン63CS(東洋紡績株式会社社製)に対して、硬化剤(メラミン樹脂:サイメル303、三井化学株式会社製)および硬化触媒(キャタリスト4050、三井化学株式会社製)を、固形分換算で30:6:0.03の質量比率となるように添加し、これを混合して、ベース塗料を作製した。 Base paint: Byron 63CS (manufactured by Toyobo Co., Ltd.) as a main resin, a curing agent (melamine resin: Cymel 303, manufactured by Mitsui Chemicals) and a curing catalyst (catalyst 4050, Mitsui Chemicals, Inc.) (Made by company) was added so that it might become a mass ratio of 30: 6: 0.03 in conversion of solid content, this was mixed, and the base coating material was produced.
A)白系塗料の作製
上記ベース塗料を用い、塗料固形分に対して顔料成分であるチタニア(CR−90、石原産業株式会社製)を25%、多孔質シリカ(H−31、AGC 株式会社エスアイテック製)を5%加え、十分に顔料を分散させ白系塗料を作製した。
A) Preparation of white paint Using the above base paint, 25% titania (CR-90, manufactured by Ishihara Sangyo Co., Ltd.), which is a pigment component, and porous silica (H-31, AGC Corporation S) 5% of ITEC) was added, and the pigment was sufficiently dispersed to prepare a white paint.
B)黒系塗料の作製
上記ベース塗料を用い、塗料固形分に対して顔料成分であるカーボンブラック(M−100、三菱化学株式会社製)を5%、多孔質シリカ(H−31、AGC エスアイテック社製)を5%加え、十分に顔料を分散させ黒系塗料を作製した。
B) Preparation of black paint Using the above base paint, 5% of carbon black (M-100, manufactured by Mitsubishi Chemical Corporation), which is a pigment component, and porous silica (H-31, AGC S) 5% of ITEC) was added, and the pigment was sufficiently dispersed to prepare a black paint.
なお、白系、黒系のいずれの塗料についても、顔料の分散については、塗料100gに対してガラスビーズを20g混ぜ、ハイブリッドミキサーで20分間攪拌し、塗料に添加した顔料を塗料中に均一に分散させた。その後、ガラスビーズのみを濾過した。 For both white and black paints, the pigment is dispersed by mixing 20 g of glass beads with 100 g of paint and stirring for 20 minutes with a hybrid mixer to uniformly disperse the pigment added to the paint in the paint. I let you. Thereafter, only the glass beads were filtered.
上記白系、黒系塗料で用いた顔料の詳細については、表6中に示す。
次に、おもて面の化成処理皮膜上にバーコーターを用いて上記白系、黒系の塗料を塗布し、板の到達温度が40秒で210℃となるように加熱し、おもて面の下塗り塗膜を形成した。シンナー(シクロヘキサノンとソルベッソ150を1:1に混合した溶媒)の添加量、バーコーターの番手を変更することで膜厚調整を行い、1,2,3μmの各色3種類の膜厚の下塗り塗膜を得た。
Details of the pigments used in the white and black paints are shown in Table 6.
Next, the above-mentioned white and black paints are applied onto the chemical conversion coating on the front surface using a bar coater and heated so that the temperature reached by the plate is 210 ° C. in 40 seconds. An undercoat film was formed. Adjust the film thickness by changing the amount of thinner (a solvent in which cyclohexanone and Solvesso 150 are mixed 1: 1) and the number of the bar coater. Undercoat films of three different thicknesses of 1, 2, and 3 μm Got.
続いて、おもて面の下塗り塗膜上に上記の黒系塗料を塗布し、板の到達温度が50秒で230℃となるように加熱し、おもて面の上塗り塗膜を形成した。シンナーの添加、バーコーターの番手を変更することで膜厚調整を行い、1,2,3,4μmの各色4種類の膜厚の上塗り塗膜を得た。 Subsequently, the above black paint was applied onto the undercoat film on the front surface, and the plate was heated to reach 230 ° C. in 50 seconds to form an upper coat film on the front surface. . The film thickness was adjusted by adding thinner and changing the number of the bar coater to obtain top coat films of four types of film thicknesses of 1, 2, 3, and 4 μm.
こうして得られた24種類(下塗り塗料種2種類×下塗り塗膜厚さが3種類×上塗り塗膜厚さが4種類)の試験片について、次の方法で色調を測定した。
ミノルタ株式会社製の色彩色差計CR−300を用い、各塗装サンプルの色調(L*、a*、b*)を測定した。測定点は、各サンプル5点測定し、平均値を算出した。
With respect to the 24 types of test pieces thus obtained (2 types of undercoat paint types × 3 types of undercoat film thickness × 4 types of topcoat film thickness), the color tone was measured by the following method.
The color tone (L *, a *, b *) of each coating sample was measured using a color difference meter CR-300 manufactured by Minolta Co., Ltd. The measurement points were measured at 5 points for each sample, and the average value was calculated.
測定結果を表1〜4に示す。 The measurement results are shown in Tables 1 to 4.
表1および2は、最外層塗膜の膜厚を固定して下層塗膜の膜厚を変化させたときのL*値の変動を示すためのものであり、表1は下層塗膜が黒色の場合の結果を、表2は下層塗膜が白色の場合の結果を示している。 Tables 1 and 2 are for showing the variation of the L * value when the film thickness of the lower layer coating film is changed while fixing the film thickness of the outermost layer coating film. Table 1 shows that the lower layer coating film is black. Table 2 shows the results when the lower layer coating is white.
表1および2、特に最外層塗膜の色と下層塗膜の色とが異なる場合である表2において顕著に示されるように、最外層膜厚を2μm以上とすることで、下層塗膜の膜厚が変動したことに基づくL*値の変動を抑制することが実現される。 As shown in Tables 1 and 2, particularly in Table 2 where the color of the outermost layer coating film and the color of the lower layer coating film are different, by setting the outermost layer film thickness to 2 μm or more, It is possible to suppress the variation of the L * value based on the variation of the film thickness.
表3および4は、下層塗膜の膜厚を固定して最外層塗膜の膜厚を変化させたときのL*値の変動を示すためのものであり、表3は下層塗膜が黒色の場合の結果を、表4は下層塗膜が白色の場合の結果を示している。 Tables 3 and 4 are for showing the variation of the L * value when the film thickness of the outermost layer coating film is changed while fixing the film thickness of the lower layer coating film. Table 3 shows that the lower layer coating film is black. Table 4 shows the results when the lower layer coating is white.
表3および4に示されるように、最外層塗膜厚が3μmの場合には、最外層塗膜厚が±1μm変動したとしても、そのときのL*値の変動幅は比較的小さくなる。したがって、最外層塗膜厚を3μm以上とすることにより、最外層塗膜厚のばらつきに起因するL*値の変動が特に抑制されることを、これらの表から確認することができる。 As shown in Tables 3 and 4, when the outermost layer coating film thickness is 3 μm, even if the outermost layer coating film thickness varies by ± 1 μm, the fluctuation range of the L * value at that time is relatively small. Therefore, it can be confirmed from these tables that the variation of the L * value due to the variation in the thickness of the outermost layer coating film is particularly suppressed by setting the outermost layer coating film thickness to 3 μm or more.
(実施例2)
(1)試験片の作製
A)基材の準備
基材として、表5に示す合金化溶融亜鉛めっき鋼板(GA)、電気亜鉛めっき鋼板(EG)、溶融亜鉛めっき鋼板(GI)の3種類を使用した。鋼板はいずれも250×300mmのサイズであり、厚みは0.5mmであった。
(Example 2)
(1) Preparation of test piece A) Preparation of base material As the base material, three types of alloyed hot dip galvanized steel sheet (GA), electrogalvanized steel sheet (EG) and hot dip galvanized steel sheet (GI) shown in Table 5 were used. used. All the steel plates were 250 × 300 mm in size and 0.5 mm in thickness.
各基材めっき鋼板の両面に、常法に従ってアルカリ脱脂及び水洗を行った後、下記に示す工程を行い、塗装鋼板を作製した。 After performing alkali degreasing and water washing on both surfaces of each substrate-plated steel sheet according to a conventional method, the following steps were performed to prepare a coated steel sheet.
B)おもて面化成処理
市販の化成処理液(日本ペイント株式会社製EC2330)をSi換算で5mg/m2となるように塗布し、板の到達温度が10秒で80℃になるように加熱し、おもて面の化成処理皮膜を形成した。
B) Front surface chemical conversion treatment A commercially available chemical conversion treatment solution (EC2330 manufactured by Nippon Paint Co., Ltd.) is applied so as to be 5 mg / m 2 in terms of Si, so that the ultimate temperature of the plate is 80 ° C. in 10 seconds. Heating was performed to form a chemical conversion coating on the front surface.
C)うら面化成処理
市販の化成処理液(日本パーカライジング株式会社製CT−E300)を皮膜付着量として500mg/m2となるように塗布し、板の到達温度が10秒で80℃になるように加熱し、うら面の化成処理皮膜を形成した。
C) Back surface chemical conversion treatment A commercially available chemical conversion treatment solution (CT-E300 manufactured by Nihon Parkerizing Co., Ltd.) was applied so that the coating amount was 500 mg / m 2 , so that the ultimate temperature of the plate reached 80 ° C. in 10 seconds. To form a back-surface chemical conversion coating.
D)下塗り塗膜
おもて面下塗り塗料として日本ファインコーティングス株式会社製のポリエステル系塗料(FLC3900プライマーのクリアタイプ、主樹脂分子量10000以上、架橋剤:メラミン、主樹脂Tg約10℃)を用い、表6に示す種々の顔料をブレンドし、表7に記載の下塗り塗料を得た。顔料の分散に際しては、塗料重量100gに対して20gのガラスビーズを入れた容器をハイブリッドミキサーで20分間攪拌することにより、塗料に添加した顔料を塗料中に均一に分散させた。その後、ガラスビーズのみを濾過した。ここで表6に示す多孔質シリカ1、2、3は防錆顔料としての多孔質シリカである。また、表6における各顔料の吸油量、比表面積、および平均一次粒径は、いずれも各顔料のカタログ記載値である。
D) Undercoating film As a front surface undercoating material, a polyester-based coating material manufactured by Nippon Fine Coatings Co., Ltd. (FLC3900 primer clear type, main resin molecular weight of 10,000 or more, cross-linking agent: melamine, main resin Tg of about 10 ° C.) The various pigments shown in Table 6 were blended to obtain the undercoat paint shown in Table 7. In dispersing the pigment, a container containing 20 g of glass beads with respect to 100 g of the paint weight was stirred for 20 minutes with a hybrid mixer, so that the pigment added to the paint was uniformly dispersed in the paint. Thereafter, only the glass beads were filtered. Here, porous silicas 1, 2, and 3 shown in Table 6 are porous silicas as antirust pigments. In Table 6, the oil absorption amount, specific surface area, and average primary particle size of each pigment are values described in the catalog of each pigment.
表7に示す下塗り用塗料をおもて面の化成処理皮膜上に塗布し、板の到達温度が40秒で210℃となるように加熱し、おもて面の下塗り塗膜を形成した。シンナー(シクロヘキサノンとソルベッソ150を1:1に混合した溶媒)の添加量、バーコーターの番手を変更することで膜厚調整を行い、1μm以上2μm以下の下層膜厚を得た。なお、表中PWC(Pigment Weight Content)は塗料固形分に対する顔料濃度(単位:質量%)を意味する。 The undercoat paint shown in Table 7 was applied onto the chemical conversion coating on the front surface and heated so that the ultimate temperature of the plate was 210 ° C. in 40 seconds to form an undercoat coating on the front surface. The film thickness was adjusted by changing the amount of thinner (a solvent in which cyclohexanone and Solvesso 150 were mixed 1: 1) and the bar coater count, and a lower layer thickness of 1 μm or more and 2 μm or less was obtained. In the table, PWC (Pigment Weight Content) means the pigment concentration (unit: mass%) relative to the solid content of the paint.
E)上塗り塗膜
下記に示す上塗り用塗料をおもて面の下塗り塗膜上に塗布し、板の到達温度が50秒で230℃となるように加熱し、おもて面の上塗り塗膜を形成した。シンナー(シクロヘキサノンとソルベッソ150を1:1に混合した溶媒)の添加量、バーコーター番手変更をすることで膜厚調整を行い、2μm以上10μm以下の最外層塗膜を得た。
E) Top coat film The top coat film shown below is applied onto the undercoat film on the front surface and heated so that the temperature reached by the plate is 230 ° C in 50 seconds. Formed. The film thickness was adjusted by changing the amount of thinner (solvent in which cyclohexanone and Solvesso 150 were mixed 1: 1) and the bar coater number, and an outermost coating film of 2 μm or more and 10 μm or less was obtained.
上塗り塗料α:日本ファインコーティングス株式会社製の高分子ポリエステル塗料FLC5000クリアタイプ(硬化剤メラミン)を用い、塗料固形分に対して、カーボンブラックを5%添加した塗料。 Topcoat paint α: A paint in which 5% of carbon black is added to the solid content of the paint using a polymer polyester paint FLC5000 clear type (hardening agent melamine) manufactured by Nippon Fine Coatings Co., Ltd.
上塗り塗料β:日本ファインコーティングス株式会社製の高分子ポリエステル塗料FLC5000クリアタイプ(硬化剤メラミン)を用い、塗料固形分に対して、カーボンブラックを5%、アルミフレークを5%添加した塗料。 Top coating paint β: A paint in which 5% carbon black and 5% aluminum flakes are added to the solid content of the coating using a polymer polyester paint FLC5000 clear type (hardening agent melamine) manufactured by Nippon Fine Coatings Co., Ltd.
上塗り塗料γ:三井化学株式会社製の低分子ポリエステル樹脂P645に硬化剤として三井化学株式会社製のサイメル303をポリエステル樹脂100gに対して10g、硬化触媒として三井化学株式会社製のキャタリスト4050を塗料100gに対して0.1g添加したクリア塗料を作製し、このクリア塗料の固形分に対してカーボンブラックを5%添加した塗料。 Top coating γ: Low molecular weight polyester resin P645 manufactured by Mitsui Chemicals Co., Ltd. 10 g of Cymel 303 manufactured by Mitsui Chemicals, Ltd. as a curing agent for 100 g of polyester resin, and Catalyst 4050 manufactured by Mitsui Chemicals, Inc. as a curing catalyst A clear paint in which 0.1 g is added to 100 g, and 5% of carbon black is added to the solid content of the clear paint.
上塗り塗料δ:三菱レイヨン株式会社製アクリル樹脂ダイヤナールHR−2011に硬化剤として三井化学株式会社製のサイメル303をアクリル樹脂100gに対して40g、硬化触媒として三井化学株式会社製のキャタリスト4050を塗料100gに対して1g添加したクリア塗料を作製し、このクリア塗料の固形分に対してカーボンブラックを5%添加した塗料。 Top coating δ: Mitsubishi Rayon Co., Ltd. acrylic resin Dianal HR-2011 with 40 g of Mitsui Chemicals Co., Ltd. as a curing agent for 100 g of acrylic resin and Mitsui Chemicals Co., Ltd., Catalyst 4050 as a curing catalyst. A clear paint in which 1 g is added to 100 g of the paint, and 5% of carbon black is added to the solid content of the clear paint.
顔料を添加した塗料の分散については、塗料100gに対してガラスビーズを20g混ぜ、ハイブリッドミキサーで20分間攪拌し、塗料に添加した顔料を塗料中に均一に分散させた。その後、ガラスビーズのみを濾過した。 Regarding the dispersion of the paint to which the pigment was added, 20 g of glass beads were mixed with 100 g of the paint and stirred for 20 minutes with a hybrid mixer to uniformly disperse the pigment added to the paint in the paint. Thereafter, only the glass beads were filtered.
F)塗装鋼板の構成
上記手順により作製した塗装鋼板の構成を表8に示す。
F) Configuration of the coated steel plate Table 8 shows the configuration of the coated steel plate produced by the above procedure.
(2)おもて面の評価
A)平面部耐食性
塗装鋼板の各試験片から70mm×150mmのサイズの評価用試験片をシャーリングにより切り出し、切断端面にシールをした後、JIS Z2371に準拠した条件で240時間の塩水噴霧試験に供した。その後、シールをした端面部分を除く平面部分からの白錆、赤錆の発生状況(面積率)を測定した。評価基準は下記のとおりであり、○以上を合格とする:
◎:白錆発生無し
○:白錆、赤錆面積率5%未満、
△:白錆、赤錆面積率5%以上、20%未満
×:白錆、赤錆面積率20%以上。
(2) Evaluation of front surface A) Plane portion corrosion resistance Conditions for compliant with JIS Z2371 after cutting out a test piece of 70 mm × 150 mm size from each test piece of a coated steel plate by shearing and sealing the cut end face And subjected to a salt spray test for 240 hours. Thereafter, the occurrence state (area ratio) of white rust and red rust from the flat surface portion excluding the sealed end surface portion was measured. The evaluation criteria are as follows, with a pass of ○ or higher:
◎: No white rust occurrence ○: White rust, red rust area ratio less than 5%,
Δ: White rust, red rust area ratio 5% or more, less than 20% ×: White rust, red rust area ratio 20% or more.
B)塗膜加工性
試験片に対して0T折り曲げ試験(23℃)を行い、180°密着曲げ塗膜についてクラック発生有無を10倍ルーペを用いて調査した。評価基準は下記のとおりであり、○以上を合格とする:
◎:まったくクラックなし、
○:ごくわずかなクラックあり(ルーペでは確認できるが、目視では確認できないレベル)、
△:若干クラックあり(目視で5個以内)、
×:かなり多くのクラックあり(目視で5個より多い)。
B) Coating film processability A 0T bending test (23 ° C.) was performed on the test piece, and the presence or absence of cracks in the 180 ° adhesion bending coating film was investigated using a 10-fold loupe. The evaluation criteria are as follows, with a pass of ○ or higher:
A: No crack at all,
○: There are very few cracks (a level that can be confirmed with a magnifying glass but cannot be visually confirmed)
Δ: Slightly cracked (within 5 visually)
X: There are quite many cracks (more than 5 visually).
C)硬度試験
JIS K5600−5−4(引っかき硬度(鉛筆法))の方法に従って測定した。硬度がH以上の場合を良好とした。
C) Hardness test Measured according to the method of JIS K5600-5-4 (scratch hardness (pencil method)). The case where the hardness was H or higher was considered good.
D)塗膜最表層のヤング率測定
株式会社フィッシャー・インストルメンツ社製フィッシャースコープHM−2000を用い、下記方法にて塗膜最表面のヤング率を求めた。
D) Measurement of Young's modulus of outermost layer of coating film Using a Fisherscope HM-2000 manufactured by Fischer Instruments Co., Ltd., Young's modulus of the outermost surface of the coating film was determined by the following method.
サンプル設置方法:シャーリングで20mm×20mmの大きさに切断した塗装サンプルを、フィッシャースコープHM−2000の測定ステージ上に塗装面を上にして設置した。 Sample installation method: A painted sample cut to a size of 20 mm × 20 mm by shearing was placed on the measurement stage of the Fisherscope HM-2000 with the coating surface up.
測定条件:測定条件は次のとおりである。
押し込み最大荷重:2mN
荷重付加時のアプリケーション時間 : 20s
クリープ時間 : 5s
荷重減少時のアプリケーション時間 : 20s
圧子型 : 四角錐(ビッカース圧子)
測定温度:23℃
測定数:各サンプル30点ずつ測定し、ヤング率を求め、最大値から数値の大きい順に5点、最小値から数値の小さい順に5点を取り除き、残り20点の平均値を塗膜最表面のヤング率を求めた。
評価基準として、ヤング率が5GPaを超えるものを×、5GPa以内のものを○とした。
Measurement conditions: The measurement conditions are as follows.
Push-in maximum load: 2mN
Application time when load is applied: 20s
Creep time: 5s
Application time when load decreases: 20s
Indenter type: Square pyramid (Vickers indenter)
Measurement temperature: 23 ° C
Number of measurements: Measure 30 points for each sample, determine Young's modulus, remove 5 points from largest value to largest numerical value, remove 5 points from smallest value to smallest numerical value, and average the remaining 20 points on the outermost surface of the coating Young's modulus was determined.
As an evaluation standard, a sample having a Young's modulus exceeding 5 GPa was evaluated as x and a sample having a modulus within 5 GPa was evaluated as ◯.
E)熱放射率測定
熱放射率は、次のようにして求めた。バイオ・ラッド・ラボラトリーズ株式会社製の赤外吸収スペクトル測定装置を使用して、2.5μmから25μmの波長領域の分光反射スペクトル(R(λ))を測定した。この分光反射スペクトル(R(λ))を下記式(1)に代入し、積分範囲を2.5〜25μmとして、熱放射率を求めた。
E) Measurement of thermal emissivity The thermal emissivity was determined as follows. The spectral reflection spectrum (R (λ)) in the wavelength region of 2.5 μm to 25 μm was measured using an infrared absorption spectrum measuring apparatus manufactured by Bio-Rad Laboratories. This spectral reflection spectrum (R (λ)) was substituted into the following formula (1), and the thermal emissivity was determined by setting the integration range to 2.5 to 25 μm.
ここで、α:熱放射率(%)、G(λ):プランクの熱放射スペクトル分布において絶対温度293Kとした場合の相対値、R(λ):分光光度計により測定された分光反射率である。 Where α: thermal emissivity (%), G (λ): relative value when the absolute temperature is 293K in the Planck's thermal radiation spectrum distribution, R (λ): spectral reflectance measured by a spectrophotometer is there.
評価基準として、熱放射率が40%以上のものを○(良好)、40%未満のものを×(不良)とした。
上記の評価を行った結果を表8に示す。また、表4におけるNo.38,39,40,41および42の耐食性評価後の状態を図1〜5に示す。
As evaluation criteria, those having a thermal emissivity of 40% or more were evaluated as ◯ (good), and those having a thermal emissivity of less than 40% were evaluated as x (defective).
Table 8 shows the results of the above evaluation. In Table 4, No. The state after the corrosion resistance evaluation of 38, 39, 40, 41 and 42 is shown in FIGS.
Claims (7)
前記塗膜層の厚さが10μm以下であり、
前記2層以上の塗膜のうち最外層をなす塗膜である最外層塗膜が、塗料固形分に対して5質量%以上50質量%以下の着色顔料を含むとともに、膜厚が2μm以上かつ塗膜最表面のヤング率が5GPa以下であって、
前記最外層塗膜以外の塗膜である下層塗膜が、塗料固形分に対して5質量%以上30質量%以下の顔料を含むとともに膜厚が2μm以上である塗膜を備え、当該塗膜に含有される顔料が、吸油量:100ml/100g以上1000ml/100g以下かつ比表面積:100m2/g以上1000m2/g以下を満たす防錆顔料としての多孔質シリカを、塗料固形分に対して5質量%以上30質量%以下含むことを特徴とする塗装鋼板。 A coated steel sheet provided with a coating layer comprising two or more coating layers on the surface subjected to chemical conversion treatment,
The coating layer has a thickness of 10 μm or less,
The outermost coating film which is the coating film forming the outermost layer among the two or more coating films contains a coloring pigment of 5% by mass or more and 50% by mass or less with respect to the solid content of the paint, and has a film thickness of 2 μm or more and The Young's modulus of the outermost surface of the coating is 5 GPa or less,
A lower layer coating film which is a coating film other than the outermost layer coating film includes a coating film having a film thickness of 2 μm or more and containing a pigment of 5% by mass to 30% by mass with respect to the solid content of the coating, The porous silica as a rust-preventing pigment satisfying the paint solid content is the oil absorption amount: 100 ml / 100 g or more and 1000 ml / 100 g or less and the specific surface area: 100 m 2 / g or more and 1000 m 2 / g or less. A coated steel sheet comprising 5% by mass or more and 30% by mass or less.
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JP2013018192A (en) * | 2011-07-11 | 2013-01-31 | Nippon Steel & Sumitomo Metal Corp | Surface-treated steel plate and casing for home electric appliance |
JP2013108051A (en) * | 2011-10-25 | 2013-06-06 | Jfe Steel Corp | Coating agent, method for producing coated steel sheet and coated steel sheet |
JP2014015037A (en) * | 2012-06-11 | 2014-01-30 | Kobe Steel Ltd | Metal sheet coated with black thin film |
CN105682916A (en) * | 2013-10-29 | 2016-06-15 | 株式会社神户制钢所 | Black coated metal plate |
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JP2007289889A (en) * | 2006-04-26 | 2007-11-08 | Sumitomo Metal Ind Ltd | Coated steel sheet excellent in corrosion resistance |
JP2008238814A (en) * | 2007-02-28 | 2008-10-09 | Jfe Steel Kk | Coated steel sheet, processed article, and panel for flat screen television |
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WO2005105432A1 (en) * | 2004-04-28 | 2005-11-10 | Sumitomo Metal Industries, Ltd. | Coated steel sheet with excellent heat dissipation |
JP2007289889A (en) * | 2006-04-26 | 2007-11-08 | Sumitomo Metal Ind Ltd | Coated steel sheet excellent in corrosion resistance |
JP2008238814A (en) * | 2007-02-28 | 2008-10-09 | Jfe Steel Kk | Coated steel sheet, processed article, and panel for flat screen television |
Cited By (8)
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JP2013018192A (en) * | 2011-07-11 | 2013-01-31 | Nippon Steel & Sumitomo Metal Corp | Surface-treated steel plate and casing for home electric appliance |
JP2013108051A (en) * | 2011-10-25 | 2013-06-06 | Jfe Steel Corp | Coating agent, method for producing coated steel sheet and coated steel sheet |
JP2014015037A (en) * | 2012-06-11 | 2014-01-30 | Kobe Steel Ltd | Metal sheet coated with black thin film |
TWI618629B (en) * | 2012-06-11 | 2018-03-21 | 神戶製鋼所股份有限公司 | Thin-black-layer-coated metal sheet |
CN105682916A (en) * | 2013-10-29 | 2016-06-15 | 株式会社神户制钢所 | Black coated metal plate |
KR20160077126A (en) | 2013-10-29 | 2016-07-01 | 가부시키가이샤 고베 세이코쇼 | Black coated metal plate |
CN105682916B (en) * | 2013-10-29 | 2018-04-06 | 株式会社神户制钢所 | black coated metal plate |
CN116044915A (en) * | 2023-01-16 | 2023-05-02 | 泰尔重工股份有限公司 | Universal coupler fork end face tooth, manufacturing method thereof and universal coupler |
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