JP2975550B2 - Pre-coated fin material for heat exchanger - Google Patents
Pre-coated fin material for heat exchangerInfo
- Publication number
- JP2975550B2 JP2975550B2 JP16697695A JP16697695A JP2975550B2 JP 2975550 B2 JP2975550 B2 JP 2975550B2 JP 16697695 A JP16697695 A JP 16697695A JP 16697695 A JP16697695 A JP 16697695A JP 2975550 B2 JP2975550 B2 JP 2975550B2
- Authority
- JP
- Japan
- Prior art keywords
- resin
- hydrophilic
- fin material
- aluminum
- polyvinyl alcohol
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired - Lifetime
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Description
【0001】[0001]
【産業上の利用分野】本発明は、業務用、家庭用エアコ
ンのコンデンサー、エバポレーター等に用いる熱交換器
あるいは自動車用ラジエータ等の熱交換器に用いられる
アルミニウムもしくはアルミニウム合金(以下アルミニ
ウムまたはアルミニウム合金を単にアルミニウム等とい
う。)製熱交換器用プレコートフィン材に関し、特に表
面に親水性の優れた被覆層を形成し、熱交換器用プレコ
ートフィン材に関するものである。BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to aluminum or aluminum alloy (hereinafter referred to as aluminum or aluminum alloy) used for heat exchangers used for condensers and evaporators of commercial and home air conditioners and radiators for automobiles. The present invention relates to a precoated fin material for a heat exchanger, and more particularly to a precoated fin material for a heat exchanger having a coating layer having excellent hydrophilicity formed on the surface.
【0002】[0002]
【従来の技術】熱交換器用フィン材としては、軽量でか
つ加工性、熱伝導性に優れたアルミニウムが従来から広
く用いられている。近年、ルームエアコン等のコンパク
ト化、省エネルギーに対する要求から伝導効率をさらに
高める工夫がなされ、ルーバーを立ち起したり、フィン
とフィンの距離を短くする等を行うようになった。この
ため、フィン上に水が凝縮したときは水滴がフィン間に
ブリッジを形成し、そのため通風抵抗が増加したり、こ
の水滴が通風と共振を起して騒音を発生する、さらには
凝縮水によるフィン材の腐食といった不具合も同時に生
じ始めた。そこでこれを改善するべくフィン材を耐食性
処理をすると共に、親水化処理(水凝縮時の接触角を下
げ水滴とならないようにする)が施されるようになっ
た。また、生産性を高めるため、従来のフィン成形、組
立後、親水化処理するポストコートに代わり、アルミニ
ウム薄板にあらかじめ親水化処理し、それを成形するプ
レコート化が進んでいる。その結果、熱交換器用アルミ
ニウムフィン材に親水性と共に成形性が求められてい
る。2. Description of the Related Art As a fin material for a heat exchanger, aluminum, which is lightweight and excellent in workability and heat conductivity, has been widely used. In recent years, due to demands for downsizing and energy saving of room air conditioners and the like, measures have been devised to further increase the conduction efficiency, such as raising louvers and shortening the distance between fins. For this reason, when water condenses on the fins, the water droplets form a bridge between the fins, thereby increasing the ventilation resistance and causing the water droplets to resonate with the ventilation and generate noise. Problems such as corrosion of the fin material began to occur at the same time. Therefore, in order to improve this, the fin material is subjected to a corrosion resistance treatment and a hydrophilic treatment (a contact angle at the time of condensation of water is reduced to prevent water droplets). Further, in order to increase productivity, instead of the conventional fin molding, post-coating after assembling and post-assembly treatment, an aluminum sheet is preliminarily subjected to hydrophilization treatment and pre-coating to form the same. As a result, aluminum fin materials for heat exchangers are required to have moldability as well as hydrophilicity.
【0003】このような要求に対し、以下のような種々
の親水性樹脂組成物、親水性無機化合物組成物およびそ
れらを塗布したフィン材が提案されている。大別すると
有機樹脂を中心とした有機系とシリカ等の無機系を中心
とした無機系とに分けられる。有機系については、ナト
リウム、カリウム、アンモニウム等のカルボキシメチル
セルロース塩に架橋剤としてN−メチロールアミドを配
合した樹脂組成物(特開平3−252461)、スルホ
ン酸基またはその塩が導入された水溶性有機高分子化合
物に水溶性有機高分子化合物を加えた組成物(特開平6
−50690)などのように親水性樹脂または親水性物
質に架橋剤を添加し、塗布、焼き付けの際に高分子化
し、親水性を維持しながら耐水性(水中への溶出防止)
を両立させようとする考え方が一般的である。[0003] In response to such demands, various kinds of hydrophilic resin compositions, hydrophilic inorganic compound compositions, and fin materials coated with the following have been proposed. It can be broadly classified into an organic type mainly composed of an organic resin and an inorganic type mainly composed of an inorganic type such as silica. Regarding organic compounds, a resin composition (Japanese Patent Laid-Open No. 3-252461) in which N-methylolamide is blended as a crosslinking agent with a carboxymethylcellulose salt such as sodium, potassium, ammonium or the like, a water-soluble organic compound having a sulfonic acid group or a salt thereof introduced. Composition comprising a polymer compound and a water-soluble organic polymer compound
-50690), a cross-linking agent is added to a hydrophilic resin or a hydrophilic substance, polymerized during application and baking, and water resistant while maintaining hydrophilicity (prevention of elution into water)
The idea of trying to balance both is common.
【0004】しかし、このような樹脂組成物では、塗膜
形成直後は良好な親水性を発揮するものの、表面に水分
が長時間付着していると、架橋した結合が切れ、低分子
化した親水性物質が溶出するとともに、架橋剤成分は塗
布表面に残留するため、塗布表面の架橋剤成分濃度はし
だいに増加する。この結果、塗膜中に残った架橋剤は塗
膜中の別の親水基と架橋結合形成をするため、結果的に
樹脂組成物の架橋密度が高くなりすぎ、親水性がしだい
に低下し、親水性持続性の低下を引き起こす。一方、無
機系親水性組成物またはそれを塗布したフィン材につい
ても数々の提案がなされている。無機系親水性組成物
は、特開昭62−235477に開示されているような
アルカリケイ酸塩に、若干量の有機樹脂をバインダ−と
して添加した組成物またはそれを塗布したフィン材が基
本である。しかし、このような無機系親水性組成物には
固いシリカ粒子が多量に含まれているため、有機系親水
性樹脂組成物に比べ成形しにくく、金型の摩耗も大きい
ものであった。さらに現在においては、環境汚染の低減
のために従来使用されていた成形後に洗浄を必要とする
プレスオイルに代わり、成形後洗浄を必要としない揮発
性のプレスオイルが使用されるようになった。このよう
な揮発性プレスオイルを使用すると、成形の難しさおよ
び金型摩耗が助長されるため、無機系親水性組成物では
長期間安定した親水性と成形性の要求を同時に満たすこ
とは難しい問題であった。[0004] However, such a resin composition exhibits good hydrophilicity immediately after the formation of a coating film, but when moisture adheres to the surface for a long time, the crosslinked bond is broken and the low molecular weight hydrophilicity is reduced. Since the active substance elutes and the crosslinking agent component remains on the coating surface, the concentration of the crosslinking agent component on the coating surface gradually increases. As a result, the cross-linking agent remaining in the coating film forms a cross-linking bond with another hydrophilic group in the coating film.As a result, the cross-linking density of the resin composition becomes too high, and the hydrophilicity gradually decreases, Causes a reduction in hydrophilic persistence. On the other hand, various proposals have also been made regarding an inorganic hydrophilic composition or a fin material coated with the composition. The inorganic hydrophilic composition is basically a composition in which a small amount of an organic resin is added as a binder to an alkali silicate as disclosed in JP-A-62-235377, or a fin material coated with the composition. is there. However, since such an inorganic hydrophilic composition contains a large amount of hard silica particles, it is harder to mold than an organic hydrophilic resin composition, and abrasion of a mold is large. Further, at present, a volatile press oil which does not require cleaning after molding has been used instead of a press oil which requires cleaning after molding, which has been conventionally used to reduce environmental pollution. When such a volatile press oil is used, molding difficulty and mold wear are promoted, so that it is difficult to simultaneously satisfy long-term stable hydrophilicity and moldability requirements with an inorganic hydrophilic composition. Met.
【0005】[0005]
【発明が解決しようとする課題】本発明は、長期間の使
用においてもアルミニウムフィン上に水分が凝縮しても
粗大な水滴となってフィン表面上に止まらずに、薄い水
層となって流れ落ちる塗膜を有し、またこの塗膜は耐食
性に優れていて、水分、湿度による腐食を防止できると
共に、低沸点、低粘度の揮発性のプレスオイルを使用し
た場合においても良好な成形性を有する熱交換器用プレ
コートフィン材およびその製造方法の開発を目的とす
る。According to the present invention, even when water is condensed on aluminum fins even when used for a long time, the water does not stop as coarse water droplets on the fin surface but flows down as a thin water layer. It has a coating film, and this coating film has excellent corrosion resistance, can prevent corrosion due to moisture and humidity, and has good moldability even when a low boiling point, low viscosity volatile press oil is used. An object of the present invention is to develop a precoated fin material for a heat exchanger and a method for producing the same.
【0006】[0006]
【課題を解決するための手段】本発明は、アルミニウム
等の薄板上に、分子内架橋剤以外の架橋剤を含まないア
クリル系樹脂およびポリビニルアルコール系樹脂を主成
分とする親水性樹脂を塗装、焼き付けし、表面が高さ
0.05〜0.2μmのタイル状突起を敷きつめた構造
を有し、このタイル状突起が0.5〜1.5個/μm2
の割合で存在する熱交換器用プレコートフィン材を開発
することにより上記の課題を解決した。さらにこの熱交
換器用プレコートフィン材はアルミニウム等の薄板上
に、分子内架橋剤以外の架橋剤を含まないアクリル系樹
脂およびポリビニルアルコール系樹脂を主成分とする親
水性樹脂を塗装し、焼き付け温度150〜250℃、焼
き付け時間5秒以上行うことによる熱交換器用プレコー
トフィン材の製造方法によって得ることができる。According to the present invention, there is provided a thin plate of aluminum or the like coated with a hydrophilic resin mainly containing an acrylic resin and a polyvinyl alcohol resin not containing a crosslinking agent other than an intramolecular crosslinking agent. It is baked and has a structure in which tile-like protrusions having a surface of 0.05 to 0.2 μm are laid, and the number of such tile-like protrusions is 0.5 to 1.5 / μm 2.
The above-mentioned problem was solved by developing a pre-coated fin material for a heat exchanger which is present at a ratio of (1). Further, this pre-coated fin material for a heat exchanger is coated on a thin plate of aluminum or the like with a hydrophilic resin mainly composed of an acrylic resin and a polyvinyl alcohol-based resin not containing a crosslinking agent other than an intramolecular crosslinking agent. It can be obtained by a method for producing a precoated fin material for a heat exchanger by performing a baking time of 5 seconds or more at 250 ° C.
【0007】本発明の熱交換器用フィン材に用いられる
アルミニウム等薄板としては、JIS規格で、110
0、1050、1N30等の純アルミニウム板、201
7、2024等のAl−Cu系合金板、3003、30
04等のAl−Mn系合金板、5052、5083等の
Al−Mg系合金板、さらには6061等のAl−Mg
−Si系合金板等のいずれを用いても良く、またその形
状はシートおよびコイルのいずれでも良い。この発明の
熱交換器用フィン材を製造するにあたっては、上述のよ
うなアルミニウム等薄板に対して脱脂、水洗、乾燥を行
った後、架橋剤を含まないアクリル系樹脂およびポリビ
ニルアルコール系樹脂を主成分とする親水性樹脂を塗
装、焼き付けする。As a thin plate made of aluminum or the like used for the fin material for a heat exchanger of the present invention, 110
0, 1050, pure aluminum plate such as 1N30, 201
7, 2024, etc., Al-Cu alloy plates, 3003, 30
Al-Mn alloy plates such as 04, 5052, 5083, etc., and Al-Mg plates such as 6061
Any of a -Si alloy plate or the like may be used, and the shape may be any of a sheet and a coil. In producing the heat exchanger fin material of the present invention, the above-described thin plate such as aluminum is degreased, washed with water, and dried, and then mainly contains an acrylic resin and a polyvinyl alcohol resin containing no crosslinking agent. Is coated and baked.
【0008】この場合、親水性樹脂塗装に先立ち、耐食
性、塗膜密着性向上のための下地処理を施しても良い。
例えば、アルミニウム等薄板を、pH=9〜13、浴温
35〜85℃のアルカリ性水溶液中で、電流密度4〜5
0A/dm2 にて、電気量が80C/dm2 を越えるこ
ととなる時間、交流電解処理を行い、アルミニウム等薄
板表面に膜厚500〜5000Åの酸化皮膜を形成させ
る方法(特願平2−109341号)、あるいはアルミ
ニウム板材にポリアクリル酸、ポリメタクリル酸ポリア
クリル酸誘導体、ポリメタクリル酸誘導体、ウレタン樹
脂、ウレタン樹脂誘導体、エポキシ樹脂、エポキシ樹脂
誘導体、ポリアミド、ポリアミド誘導体等のいずれか、
またはこれらの内の2種以上の共重合体または混合物あ
るいはさらに3価クロム、6価クロム、SiO2 、ケイ
酸塩、ジルコニウム塩等を含む塗料を0.4〜5μmの
厚さに塗布し、焼き付けて耐食性皮膜を形成する方法
(特開昭61−107198号、特開平1−22579
5号)またはアルミニウム板材をスプレー、浸漬などの
方法でりん酸クロメートまたはクロム酸クロメート処理
を行い、クロム付着量5〜100mg/m2 の皮膜を形
成する方法(特開昭62−105629号)などの方法
があるが、これらの方法に限定されるわけではない。In this case, prior to the hydrophilic resin coating, a base treatment for improving corrosion resistance and coating film adhesion may be performed.
For example, a thin plate of aluminum or the like is subjected to a current density of 4 to 5 in an alkaline aqueous solution having a pH of 9 to 13 and a bath temperature of 35 to 85 ° C.
A method of forming an oxide film having a thickness of 500 to 5000 ° on a thin plate made of aluminum or the like by conducting an alternating current electrolytic treatment at 0 A / dm 2 for a time when the amount of electricity exceeds 80 C / dm 2 (Japanese Patent Application No. Hei. No. 109341) or polyacrylic acid, polymethacrylic acid polyacrylic acid derivative, polymethacrylic acid derivative, urethane resin, urethane resin derivative, epoxy resin, epoxy resin derivative, polyamide, polyamide derivative, etc.
Or a paint containing at least 0.4 or 5 μm of a copolymer or mixture of two or more of these, or a paint containing trivalent chromium, hexavalent chromium, SiO 2 , silicate, zirconium salt, etc., A method of forming a corrosion-resistant film by baking (JP-A-61-107198, JP-A-1-2579)
No. 5) or a method in which an aluminum plate material is subjected to phosphoric acid chromate or chromate chromate treatment by a method such as spraying or dipping to form a film having a chromium adhesion amount of 5 to 100 mg / m 2 (Japanese Patent Application Laid-Open No. 62-105629). However, the method is not limited to these methods.
【0009】本発明に使用する親水性樹脂は、メラミン
樹脂、尿素樹脂、エポキシ樹脂、イソシアネート系化合
物などの架橋剤成分を含んではならず、また界面活性剤
も含んでいないアクリル系樹脂およびポリビニルアルコ
ール系樹脂を主成分とした水、アルコールまたはそれら
の混合溶媒の溶液である。アクリル系樹脂としては、ア
クリル酸;アルカリ金属塩、アンモニウム塩あるいは低
級アルキルアミン塩などのアクリル酸塩類;アクリル酸
メチル、アクリル酸エチル、アクリル酸プロピル等の低
級アクリル酸エステル類;メタクリル酸;アルカリ金属
塩、アンモニウム塩あるいは低級アルキルアミン塩など
のメタクリル酸塩類、メタクリル酸メチル、メタクリル
酸エチル、メタクリル酸ブチル等の低級メタクリル酸エ
ステル類等の重合体または共重合体を挙げることができ
る。The hydrophilic resin used in the present invention does not contain a crosslinking agent component such as a melamine resin, a urea resin, an epoxy resin, an isocyanate compound, and an acrylic resin and a polyvinyl alcohol which do not contain a surfactant. This is a solution of water, alcohol, or a mixed solvent thereof containing a base resin as a main component. Acrylic resins include acrylic acid; acrylates such as alkali metal salts, ammonium salts and lower alkylamine salts; lower acrylates such as methyl acrylate, ethyl acrylate and propyl acrylate; methacrylic acid; Examples thereof include polymers or copolymers of methacrylates such as salts, ammonium salts and lower alkylamine salts, and lower methacrylates such as methyl methacrylate, ethyl methacrylate and butyl methacrylate.
【0010】ポリビニルアルコール系樹脂としては、ポ
リビニルアルコールまたはその水酸基の一部がアクリル
酸、メタクリル酸、マレイン酸、ビニルスルホン酸等の
カルボキシル基またはスルホン酸基を含有するエステル
化合物の共重合物、アクリル酸エステル重合体の加水分
解物のようなアニオン性置換基あるいは第1級〜第3級
アミノ基、第4級アンモニウム基などのカチオン性置換
基等により変性させた樹脂が好ましい。本発明の親水性
樹脂は、上記アクリル系樹脂およびポリビニルアルコー
ル系樹脂を混合した形で用いる。この混合割合は、アク
リル系樹脂として20重量%を超え70重量%未満、ポ
リビニルアルコール系樹脂として30重量%を超え、8
0重量%未満(合計100重量%)、好ましくはアクリ
ル系樹脂30〜60重量%、ポリビニルアルコール系樹
脂70〜40重量%に混合した親水性樹脂であり、水ま
たはアルコール等の溶解した溶液として取扱い易い粘
度、例えば5重量%位の濃度の溶剤としてアルミニウム
等薄板に塗装する。塗装方式は一般に使用されているロ
ールコート、スプレーコート等その方式は問わない。塗
膜厚さは、焼き付け後の突起高さが0.05〜0.2μ
mになるようであれば適宜で良いが、塗膜厚さとして少
なくとも0.1μm、好ましくは0.2〜2.0μmの
厚さに塗装する。この塗膜厚さが0.1μm未満では十
分な高さの凹凸が形成されない部分が生じる。また2.
0μmを越えても性能は変らず無駄である。Examples of the polyvinyl alcohol-based resin include polyvinyl alcohol or a copolymer of an ester compound having a carboxyl group or a sulfonic group such as acrylic acid, methacrylic acid, maleic acid, vinyl sulfonic acid or the like, a part of which has a hydroxyl group; A resin modified with an anionic substituent such as a hydrolyzate of an acid ester polymer or a cationic substituent such as a primary to tertiary amino group or a quaternary ammonium group is preferable. The hydrophilic resin of the present invention is used in the form of a mixture of the above acrylic resin and polyvinyl alcohol resin. This mixing ratio is more than 20% by weight and less than 70% by weight as the acrylic resin, more than 30% by weight as the polyvinyl alcohol-based resin, and
A hydrophilic resin mixed with less than 0% by weight (total 100% by weight), preferably 30 to 60% by weight of acrylic resin and 70 to 40% by weight of polyvinyl alcohol resin, and handled as a solution in which water or alcohol is dissolved. It is applied to a thin plate such as aluminum as a solvent having an easy viscosity, for example, a concentration of about 5% by weight. The coating method is not particularly limited, such as generally used roll coating and spray coating. As for the coating thickness, the projection height after baking is 0.05-0.2μ
m, but the coating is applied to a thickness of at least 0.1 μm, preferably 0.2 to 2.0 μm. If the thickness of the coating film is less than 0.1 μm, there will be portions where irregularities of sufficient height are not formed. Also 2.
Even if it exceeds 0 μm, the performance does not change and is useless.
【0011】アルミニウム等薄板に塗装した後焼き付け
を行うが、親水性樹脂は焼き付けの際に相分離を起こ
し、表面が凹凸を形成する。この場合、表面はタイル状
の突起で、高さ0.05〜0.2μm、サイズ0.5〜
1.5個/μm2 (サイズとしては径が0.5〜1.5
μm位の不定形のもの)のものであることが好ましい。
焼き付け温度は塗膜の自己架橋が促進され、かつ熱分解
を起こさない温度であれば良い。150〜250℃程度
が良く、特に170〜230℃程度が好ましい。焼き付
け時間は生産性を考慮して決定され、5秒以上あれば良
い。5秒未満では塗膜の自己架橋が十分でない部分が生
じる。アルミニウム等薄板上の塗膜は、このような条件
で焼き付けを行うと、その表面は適切なサイズのタイル
状の突起が形成される。尚、凹凸のサイズ、形状などは
簡単なテストにより好適条件を求めることができる。After baking is performed after coating on a thin plate such as aluminum, the hydrophilic resin undergoes phase separation at the time of baking to form irregularities on the surface. In this case, the surface is a tile-shaped protrusion, height 0.05-0.2 μm, size 0.5-
1.5 pieces / μm 2 (the diameter is 0.5 to 1.5
(inhomogeneous one having an order of μm).
The baking temperature may be a temperature at which self-crosslinking of the coating film is promoted and thermal decomposition does not occur. The temperature is preferably about 150 to 250 ° C, particularly preferably about 170 to 230 ° C. The baking time is determined in consideration of productivity, and may be 5 seconds or more. If the time is less than 5 seconds, a portion where the self-crosslinking of the coating film is not sufficient occurs. When a coating film on a thin plate of aluminum or the like is baked under such conditions, tile-like projections of an appropriate size are formed on the surface. It should be noted that suitable conditions for the size and shape of the unevenness can be determined by a simple test.
【0012】本発明の親水性樹脂は、架橋剤としての他
の化合物を含まない自己架橋型親水性樹脂であるため、
架橋結合の一部が切れ、低分子量の親水性樹脂部分が溶
出したとしても、常に表面が更新再生されるだけでしか
ない。このため架橋剤官能基濃度が高くなり、架橋密度
が高くなり親水性が低下することもない。本発明の親水
性樹脂に用いるアクリル樹脂、ポリビニルアルコール樹
脂、これらの共重合体樹脂あるいはアクリル変性ポリビ
ニルアルコール樹脂は自己架橋型とすることが可能であ
り、その構造上親水基密度も十分に高いため基材樹脂と
して極めて優れたものである。Since the hydrophilic resin of the present invention is a self-crosslinking hydrophilic resin containing no other compound as a crosslinking agent,
Even if a part of the cross-linking is broken and the low-molecular-weight hydrophilic resin part is eluted, the surface is only renewed constantly. For this reason, the functional group concentration of the crosslinking agent is increased, the crosslinking density is increased, and the hydrophilicity is not reduced. The acrylic resin, the polyvinyl alcohol resin, the copolymer resin or the acryl-modified polyvinyl alcohol resin used for the hydrophilic resin of the present invention can be of a self-crosslinking type, and the structure has a sufficiently high hydrophilic group density. It is extremely excellent as a base resin.
【0013】[0013]
【作用】従来のプレコートフィン材として使用されてい
るアルミニウム等薄板用親水性塗装材は、親水性(水溶
性)樹脂を架橋剤により架橋したものであり、水分に長
期間曝されると架橋結合が切れ、低分子量の親水性樹脂
は水中に流出し、他端の長い分子鎖を有する架橋剤成分
(疎水性)はその表面上に残る。そしてその官能基は親
水性樹脂の官能基(親水基)と結合することになる。こ
の結果フィン材表面は架橋密度の高い、親水性の低い塗
膜が残ることになり、長期間良好な親水性を維持できな
かったものと考えられる。本発明の親水性樹脂は自己架
橋型であり、架橋結合の一部が切れ、低分子量の親水性
樹脂が流出しても同じ性質の表面が再生されるので上記
の如き問題は避けられる。A hydrophilic coating material for a thin plate such as aluminum used as a conventional precoated fin material is obtained by cross-linking a hydrophilic (water-soluble) resin with a cross-linking agent. The low molecular weight hydrophilic resin flows out into the water and the crosslinker component (hydrophobic) having a long molecular chain at the other end remains on its surface. Then, the functional group bonds to the functional group (hydrophilic group) of the hydrophilic resin. As a result, it is considered that a coating film having a high crosslinking density and a low hydrophilicity was left on the fin material surface, and good hydrophilicity could not be maintained for a long period of time. Since the hydrophilic resin of the present invention is a self-crosslinking type, a part of the cross-linking is broken, and even if the low-molecular-weight hydrophilic resin flows out, the surface having the same properties is regenerated, so that the above-mentioned problems can be avoided.
【0014】本発明の塗膜面は、タイル状微小突起を有
する。塗膜表面を粗面化すると水との接触角が平滑面の
場合に比べて低下する。このことはWeuzelの式よ
り導出されることであり、本発明の親水性樹脂表面の凹
凸はフィン材表面の親水性を高める上でも極めて有効に
作用している。The surface of the coating film of the present invention has tile-shaped fine projections. When the surface of the coating film is roughened, the contact angle with water decreases as compared with the case of a smooth surface. This is derived from the Weuzel equation, and the unevenness on the surface of the hydrophilic resin of the present invention acts very effectively also in increasing the hydrophilicity of the fin material surface.
【0015】最近は、環境汚染を防ぐため、洗浄レスプ
レスオイルまたは揮発性プレスオイルと呼ばれる低沸
点、低粘度のプレスオイルが使われるために、成形中に
プレスオイルが揮発してしまい、潤滑切れとなる傾向が
高い。従って、プレコートフィン材の成形性においては
潤滑油が切れた場合の成形性=無潤滑状態での成形性を
考慮する必要がある。塗膜表面に波形、塔状または山形
の凹凸を付与すると、摩擦抵抗が大きくなり、また金型
と塗膜表面が点接触をするため、その部分の面圧が以上
に高くなり、カジリ、塗膜剥離等の成形不良を生じ易く
なる。一方、平滑な表面において潤滑油(プレスオイ
ル)が揮発した場合、金型と塗膜表面が面接触となるた
めに、全体の摩擦抵抗が大きくなり、成形不良を生じ易
くなり、また、成形中に塗膜表面全体がはぎ取られ易く
なるために親水性塗膜層の厚みが減少し、親水性、特に
経時後の親水性(親水持続性)が低下し易い。従って、
適切な面積で金型と塗膜表面が接触するように凹凸を賦
与するのが良い。即ち、ある適切な範囲内の平滑部面積
および高さを持ったタイル状突起(=台地状突起)を単
位面積あたり適当な個数配置した表面形状とすることが
好ましいものと推定している。詳細に検討してわけでは
ないので機構を明らかにできなかったが、アルミニウム
等の薄板の表面が親水性樹脂で被覆され、かつその表面
が高さが0.05〜0.2μm程度のタイル状突起の凹
凸を有する場合において、摩擦抵抗が小さく為か、カジ
リや塗膜剥離がなく、洗浄レスプレスオイルまたは揮発
性プレスオイルを使用したときでも成形性が良好なプレ
コートフィン材が得られる。[0015] Recently, since low-boiling and low-viscosity press oils called cleaning-less press oils or volatile press oils are used to prevent environmental pollution, the press oil volatilizes during molding and loses lubrication. Tends to be high. Therefore, in the formability of the precoated fin material, it is necessary to consider the formability when the lubricating oil runs out = the formability in a non-lubricated state. When corrugated, tower-shaped or mountain-shaped irregularities are imparted to the coating film surface, the frictional resistance increases, and the point of contact between the mold and the coating film surface increases. Molding defects such as film peeling are likely to occur. On the other hand, when the lubricating oil (press oil) volatilizes on a smooth surface, the mold and the coating film surface come into surface contact with each other, so that the overall frictional resistance increases and molding defects easily occur. Since the entire surface of the coating film is easily peeled off, the thickness of the hydrophilic coating film layer is reduced, and the hydrophilicity, in particular, the hydrophilicity after aging (hydrophilic persistence) is likely to be reduced. Therefore,
It is preferable to provide irregularities so that the mold and the coating film surface come into contact with an appropriate area. In other words, it is presumed that it is preferable to have a surface shape in which an appropriate number of tile-shaped projections (= plateau-shaped projections) having a smooth portion area and a height within a certain appropriate range are arranged per unit area. The mechanism could not be clarified because it was not examined in detail, but the surface of a thin plate such as aluminum was coated with a hydrophilic resin and the surface was tiled with a height of about 0.05 to 0.2 μm. In the case where the projections have projections and depressions, a precoated fin material having good formability can be obtained even if a cleaning-less press oil or a volatile press oil is used because of low frictional resistance, no galling or peeling of the coating film.
【0016】本発明においては、本発明の親水性樹脂を
塗装、焼き付けることにより径は0.5〜1.5μmの
範囲である高さ0.05〜0.2μmのタイル状突起を
敷きつめた構造を有し、このタイル状突起が0.5〜
1.5個/μm2 の割合で存在する形状のものが得られ
るので極めて好ましい。推定ではあるが突起の大きさ
(径)が1.5μmを越えると平滑部(台地状の部分)
の大きさが大きくなりすぎ、結果的に平滑な表面と同じ
になってしまい、金型との接触面積が増えすぎるために
効果が低下する。0.5μm未満では平滑部の大きさが
小さすぎるために凹凸の効果が十分に発揮されない。ま
た凹凸の高さが0.2μmを越えると揮発性プレスオイ
ル油膜を凹凸が突き抜けてしまうために潤滑性が低下す
る。高さが0.05μm未満では揮発性プレスオイルの
保持効果が小さいため、やはり潤滑性が低下する。タイ
ル状突起の密度が0.5個/μm2 未満または1.5個
/μm2 を越えると、平滑部の面積が大きくなりすぎる
ため、金型との接触面積が増え成形性が低下するものと
考えられている。In the present invention, the hydrophilic resin of the present invention is coated and baked to form tile-like projections having a diameter of 0.5 to 1.5 μm and a height of 0.05 to 0.2 μm. Having a tile-like projection of 0.5 to
It is very preferable because a shape having a shape of 1.5 particles / μm 2 can be obtained. Although it is estimated, when the size (diameter) of the protrusion exceeds 1.5 μm, a smooth portion (plateau-shaped portion)
Becomes too large, resulting in the same surface as a smooth surface, and the effect decreases because the contact area with the mold becomes too large. If it is less than 0.5 μm, the size of the smooth portion is too small, so that the effect of the unevenness is not sufficiently exhibited. On the other hand, if the height of the unevenness exceeds 0.2 μm, the unevenness penetrates through the volatile press oil film, so that the lubricity is reduced. If the height is less than 0.05 μm, the effect of holding the volatile press oil is small, so that the lubricity also decreases. If the density of the tile-like projections is less than 0.5 / μm 2 or exceeds 1.5 / μm 2 , the area of the smooth portion becomes too large, so that the contact area with the mold increases and the moldability decreases. It is believed that.
【0017】[0017]
(測定方法) タイル状突起サイズ:走査電子顕微鏡で5000倍およ
び10,000倍の倍率に拡大し、表面形状およびサイ
ズを測定した。 突起の高さ:樹脂にて試験片を固めた後、ウルトラミク
ロトームにより超薄切片を作り、透過型電子顕微鏡によ
り断面を測定した。 塗膜厚さ:蛍光X−線により塗装前の試験片のアルミニ
ウムをカウントし、塗装後塗装面から試験片をカウント
し、その前後のカウントの減量から塗膜の厚みを換算し
た。 初期親水性:塗装、焼き付け直後の水接触角を測定し
た。 親水持続性:塗装、焼き付け後、純水中に200時間浸
漬した後水接触角を測定した。 成形性は実機フィンプレスにてドローレス成形を実施し
た状況で評価した。 (成形条件) 揮発性プレスオイル:RF190(昭和シェル石油)を
使用し、しごき率は55%、成形スピードは250sp
mで実施した。 (評価) ◎:非常に良好 ○:良好 △:カラー部内面にキズ発生 ×:不良(座屈、カラー飛び発生)(Measurement method) Tile-shaped protrusion size: The surface shape and size were measured with a scanning electron microscope at a magnification of 5,000 and 10,000 times. Projection height: After the test piece was solidified with a resin, an ultra-thin section was formed with an ultramicrotome, and the cross section was measured with a transmission electron microscope. Film thickness: The aluminum of the test piece before coating was counted by X-ray fluorescence, the test piece was counted from the coated surface after coating, and the thickness of the coating film was converted from the decrease in the count before and after the coating. Initial hydrophilicity: The water contact angle immediately after painting and baking was measured. Hydrophilicity persistence: After painting and baking, immersion in pure water for 200 hours and then measuring the water contact angle. The moldability was evaluated in a situation where drawless molding was performed using an actual fin press. (Molding conditions) Volatile press oil: RF190 (Showa Shell Sekiyu) was used, ironing rate was 55%, and molding speed was 250 sp.
m. (Evaluation) :: very good :: good :: scratches on the inner surface of the color part ×: bad (buckling, color fly-out)
【0018】(実施例1、比較例1)IN30のアルミ
ニウム板(300μm)を脱脂した後、アクリル系樹脂
とポリビニルアルコール系樹脂の50:50の混合的で
ある親水性樹脂水溶液の塗膜厚みを変えて塗装を施し、
200℃で15秒焼き付けし供試材とし成形性、初期親
水性、親水持続性の評価を行った。また比較のため、従
来用いられていた板架橋剤配合のセルロース系親水性樹
脂を塗装し、同様に焼き付けしたプレコートフィン材に
ついて実施例と同じく成形性、初期親水性、親水持続性
についての評価を行った。これらの結果を表1に示す。
親水性樹脂の塗膜厚が0.1μmに到らぬ場合には成形
性は劣るが、0.1μm以上であれば特に問題はないよ
うである。ただし伝熱性が劣化するので2.0μm位以
下が好ましい。(Example 1, Comparative Example 1) After degreasing an IN30 aluminum plate (300 μm), the coating thickness of a 50:50 mixture of a hydrophilic resin aqueous solution of an acrylic resin and a polyvinyl alcohol resin was reduced. Change and paint,
It was baked at 200 ° C. for 15 seconds to obtain a test material, and the moldability, initial hydrophilicity, and hydrophilic durability were evaluated. For comparison, a pre-coated fin material coated with a conventionally used cellulosic hydrophilic resin containing a plate cross-linking agent and baked in the same manner was evaluated for moldability, initial hydrophilicity, and hydrophilic persistence in the same manner as in the example. went. Table 1 shows the results.
If the coating thickness of the hydrophilic resin is less than 0.1 μm, the moldability is poor, but if it is 0.1 μm or more, there seems to be no particular problem. However, since the heat conductivity is deteriorated, the thickness is preferably about 2.0 μm or less.
【0019】[0019]
【表1】 [Table 1]
【0020】(実施例2)実施例1と同一のアルミニウ
ム板を脱脂した後、アクリル系樹脂とポリビニルアルコ
ール系樹脂の配合比を変えた親水性樹脂水溶液を塗膜厚
み1.0μmとして塗装焼き付けした供試材について成
形性、親水持続性について評価を行った。それらの結果
を表2に示す。親水性樹脂中のアクリル系樹脂比率が2
0%以下になると、タイル状突起の小さいものが存在
し、その高さも低く、個数も減少し、成形性が低下す
る。一方アクリル系樹脂比率が70%以上になると大き
いものが増加、そのため突起個数が減少すると共に成形
性が低下する。Example 2 The same aluminum plate as in Example 1 was degreased and then baked with a hydrophilic resin aqueous solution in which the mixing ratio of an acrylic resin and a polyvinyl alcohol resin was changed to a coating film thickness of 1.0 μm. The test materials were evaluated for moldability and hydrophilic sustainability. Table 2 shows the results. Acrylic resin ratio in hydrophilic resin is 2
If it is 0% or less, there are small tile-shaped protrusions, the height of which is low, the number of the protrusions is reduced, and the moldability is reduced. On the other hand, when the acrylic resin ratio is 70% or more, large ones increase, so that the number of projections decreases and the moldability decreases.
【0021】[0021]
【表2】 [Table 2]
【0022】(実施例3)実施例1と同一のアルミニウ
ム板を脱脂した後、アクリル系樹脂45%、ポリビニル
アルコール系樹脂55%の配合比の親水性樹脂水溶液を
塗膜厚み1.0μmとして塗装し、焼き付け温度、焼き
付け時間を変えて得た供試材似ついて成形性、親水持続
性に評価を行った。それらの結果を表3に示す。焼き付
け温度が低い、低温焼付の場合においては、加工性にお
いてはまずまずの塗膜が形成するが自己架橋率が低いた
め親水性持続性が不充分である。一方焼き付け温度30
0℃の高温焼き付けでは熱分解反応が進行し、タイル状
突起が小さく、数も減少し、成形性を著しく低下させ
る。Example 3 After the same aluminum plate as in Example 1 was degreased, a hydrophilic resin aqueous solution having a blend ratio of 45% of an acrylic resin and 55% of a polyvinyl alcohol resin was applied to a coating film thickness of 1.0 μm. Then, the moldability and hydrophilicity persistence of the test materials obtained by changing the baking temperature and the baking time were evaluated. Table 3 shows the results. In the case of low baking temperature and low temperature baking, a reasonable coating film is formed in workability, but the self-crosslinking rate is low and the hydrophilicity persistence is insufficient. On the other hand, baking temperature 30
At 0 ° C. high-temperature baking, the thermal decomposition reaction proceeds, the tile-like projections are small and the number is reduced, and the moldability is significantly reduced.
【0023】[0023]
【表3】 [Table 3]
【0024】[0024]
【発明の効果】本発明は、アルミニウム等薄板の表面に
架橋剤を使用しないアクリル系樹脂およびポリビニルア
ルコール系樹脂を主成分とする親水性樹脂を塗装、焼き
付けしたものであり、その表面が微細な凹凸を有してい
る。本発明のフィン材は架橋剤を用いていないため長時
間水と接触しても架橋結合の切断、架橋密度の上昇によ
る親水性の低下が起こらない長期間低接触角の親水持続
性に優れたアルミニウム等フィン材である。特にプレス
成形の際に揮発性のプレスオイルを使用しても良好な成
形性を維持できる特徴を有しており、さらに有機高分子
系の親水性処理剤であるため揮発性プレスオイルを用い
たときであっても、プレス全型の摩耗を低く抑えること
ができ、プレコートフィン材であるため高生産性の材料
である。According to the present invention, the surface of a thin plate such as aluminum is coated and baked with a hydrophilic resin mainly composed of an acrylic resin and a polyvinyl alcohol resin without using a crosslinking agent. It has irregularities. Since the fin material of the present invention does not use a crosslinking agent, it is excellent in the long-term low contact angle hydrophilicity persistence in which the breaking of the cross-linking does not occur even if it is in contact with water for a long time, and the hydrophilicity does not decrease due to an increase in the cross-linking density. It is a fin material such as aluminum. In particular, it has the feature that good moldability can be maintained even when a volatile press oil is used during press molding, and because it is an organic polymer-based hydrophilic treatment agent, a volatile press oil is used. Even at this time, it is possible to suppress the wear of the entire press die, and it is a material with high productivity because it is a pre-coated fin material.
フロントページの続き (58)調査した分野(Int.Cl.6,DB名) F28F 1/32 F28F 13/18 Continuation of the front page (58) Field surveyed (Int.Cl. 6 , DB name) F28F 1/32 F28F 13/18
Claims (3)
薄板上に、分子内架橋剤以外の架橋剤を含まないアクリ
ル系樹脂およびポリビニルアルコール系樹脂を主成分と
する親水性樹脂を塗装、焼き付けし、表面が高さ0.0
5〜0.2μmのタイル状突起を敷きつめた構造を有
し、このタイル状突起が0.5〜1.5個/μm2 の割
合で存在する熱交換器用プレコートフィン材。1. A thin plate made of aluminum or an aluminum alloy is coated and baked with a hydrophilic resin mainly composed of an acrylic resin and a polyvinyl alcohol resin not containing a crosslinking agent other than an intramolecular crosslinking agent, so that the surface is high. 0.0
A precoated fin material for a heat exchanger having a structure in which tile-shaped projections of 5 to 0.2 μm are spread, and the tile-shaped projections are present at a ratio of 0.5 to 1.5 / μm 2 .
薄板上に、分子内架橋剤以外の架橋剤を含まないアクリ
ル系樹脂およびポリビニルアルコール系樹脂を主成分と
する親水性樹脂を塗装し、焼き付け温度150〜250
℃、焼き付け時間5秒以上の焼き付け処理を行うことを
特徴とする熱交換器用プレコートフィン材の製造方法。2. A thin plate of aluminum or an aluminum alloy is coated with a hydrophilic resin mainly containing an acrylic resin and a polyvinyl alcohol resin not containing a crosslinking agent other than an intramolecular crosslinking agent, and a baking temperature of 150 to 250.
A method for producing a precoated fin material for a heat exchanger, wherein a baking treatment is performed at a temperature of 5 ° C. for a baking time of 5 seconds or more.
ルアルコール系樹脂の配合割合がアクリル系樹脂20重
量%を超え70重量%未満、ポリビニルアルコール系樹
脂30重量%を超え80重量%未満であり、かつ塗装し
た塗膜厚が少なくとも0.1μmである請求項2記載の
熱交換器用プレコートフィン材の製造方法。3. The mixing ratio of the acrylic resin and the polyvinyl alcohol resin as hydrophilic resins is more than 20% by weight and less than 70% by weight of the acrylic resin, more than 30% by weight and less than 80% by weight of the polyvinyl alcohol resin, 3. The method for producing a precoated fin material for a heat exchanger according to claim 2, wherein the thickness of the coated film is at least 0.1 [mu] m.
Priority Applications (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
JP16697695A JP2975550B2 (en) | 1995-06-08 | 1995-06-08 | Pre-coated fin material for heat exchanger |
Applications Claiming Priority (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
JP16697695A JP2975550B2 (en) | 1995-06-08 | 1995-06-08 | Pre-coated fin material for heat exchanger |
Publications (2)
Publication Number | Publication Date |
---|---|
JPH08334295A JPH08334295A (en) | 1996-12-17 |
JP2975550B2 true JP2975550B2 (en) | 1999-11-10 |
Family
ID=15841105
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
JP16697695A Expired - Lifetime JP2975550B2 (en) | 1995-06-08 | 1995-06-08 | Pre-coated fin material for heat exchanger |
Country Status (1)
Country | Link |
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JP (1) | JP2975550B2 (en) |
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Publication number | Priority date | Publication date | Assignee | Title |
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KR100469382B1 (en) * | 2000-10-26 | 2005-01-31 | 한라공조주식회사 | Method for fabricating hydrophilic coating of heat exchanger |
-
1995
- 1995-06-08 JP JP16697695A patent/JP2975550B2/en not_active Expired - Lifetime
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Publication number | Publication date |
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JPH08334295A (en) | 1996-12-17 |
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