JP3751590B2

JP3751590B2 - Insect-proof steel sheet

Info

Publication number: JP3751590B2
Application number: JP2002381494A
Authority: JP
Inventors: 達人木澤
Original assignee: 株式会社淀川製鋼所
Priority date: 2002-12-27
Filing date: 2002-12-27
Publication date: 2006-03-01
Anticipated expiration: 2022-12-27
Also published as: JP2004209788A

Description

【０００１】
【発明の属する技術分野】
この発明は、防虫機能を備えた塗装鋼板に関する。
【０００２】
【従来の技術】
一般家屋内のフロアー及び建築構造物に使用される木部、金属部および家具類に塗布される塗料に害虫防除剤を添加して、家屋内の害虫を忌避することが、特許文献１に公知である。
【０００３】
【特許文献１】
特開平１１−３５４０５号公報
【０００４】
【発明が解決しようとする課題】
防虫剤入りの塗料を母材鋼板に塗布した塗装鋼板についてみると、薬効を発揮するのは表面に分布する防虫剤に限られる。そこで本出願人は、防虫剤の使用をより少量に抑えながらその薬効を高めることができる防虫塗装鋼板を提案した（特願２００１−３２６６５８）。そこでは、母材鋼板に着色塗膜を形成したのち、その表面に防虫剤入りのクリア塗膜をトップ層として形成した。
【０００５】
しかし、この防虫塗装鋼板では、製造当初は防虫機能を有効に発揮するが、時間を経るにつれて防虫機能が低下して行く。もともと防虫剤は紫外線などの光エネルギーで分解され易い。クリア塗膜に防虫剤を配合したのでは、クリア塗膜の表層部のみなならず深層部に分散の防虫剤までもが紫外線の透過により早期に分解されるからである。
【０００６】
本発明者は、着色塗膜（エナメル層）に防虫剤を配合すると、害虫忌避効果が長期に持続されることを知った。表層部にこそ分散する防虫剤は、紫外線で分解されやすいが、着色塗膜の内部に分散する防虫剤は、着色顔料により紫外線の照射が妨げられるので分解され難いことに因る。実使用時に、着色塗膜の外表面が崩壊、欠落しても、層内部の防虫剤が表面に突出して来ることにより、却って害虫忌避効果が有利に発揮されることにもなるであろう。
【０００７】
本発明はかかる知見に基づき提案された。本発明の目的は、害虫忌避効果の長期持続性が期待できる防虫塗装鋼板を得るにある。
【０００８】
【課題を解決するための手段】
この発明の防虫塗装鋼板は、図１に示すごとく、母材鋼板１の表面にトップ層として着色塗膜３が塗布形成された防虫塗装鋼板において、着色塗膜３が、ビヒクルおよび着色顔料からなる塗料本質１００重量部に対して防虫剤を0.３〜3.０重量部配合してなる着色樹脂塗料で形成されていること、着色塗膜３の乾燥膜厚が、5.０〜４０μｍに設定されていることを特徴とする。
【０００９】
本発明の母材鋼板１は、特に限定されず、例えば亜鉛めっき鋼板、亜鉛−アルミニウム系合金めっき鋼板、アルミニウムめっき鋼板、ステンレス鋼板、アルミニウム板などを用いることができる。母材鋼板の外表面には、あらかじめクロム系又は非クロム系の化成処理層（クロメート処理）が形成されている。
【００１０】
本発明の防虫塗装鋼板は、着色塗膜３がトップ層にある限り、その塗膜構成は特に限定されないが、母材鋼板１の防食性と塗膜密着性とを良好にするため、図１に示すごとく、上記の処理がされた母材鋼板１の表面に、クロム系又は非クロム系のプライマー２を塗布形成することが望まれる。このプライマー２の乾燥膜厚は、塗膜密着性、耐食性、加工性、コストなどの点から2.０〜１０μｍ、好ましくは3.０〜7.０μｍ前後に設定することができる。
【００１１】
次に、母材鋼板１の表面にプライマー２を塗装焼付けしたのち、塗料本質１００重量部に対して防虫剤0.３〜3.０重量部を均一に分散配合した着色樹脂塗料を塗布し、焼付け板温１８０〜２６０℃で焼付け、乾燥膜厚5.０〜４０μｍの着色塗膜３を形成する。
【００１２】
着色塗膜３を形成するための着色樹脂塗料は、公知のプレコート用であって、例えばエポキシ系樹脂塗料、エポキシ−ウレタン系樹脂塗料、ポリエステル系樹脂塗料、アクリル系樹脂塗料、フッ素系樹脂塗料などを用いることができ、ビヒクルおよび着色顔料からなる塗料本質には塗膜硬度、耐傷つき性その他の特性を付与するために、骨材、レベリング剤、艶消し剤などの各種助剤が添加される。また、必要に応じて効力増強剤、酸化防止剤、可塑剤、界面活性剤、抗菌剤、防かび剤などを併用できる。
【００１３】
着色樹脂塗料において、塗料本質には、意匠性の付与と紫外線による防虫剤の劣化を防ぐために、着色顔料が1.０〜２０重量％含有される。その着色顔料としては、公知の無機系着色顔料およびアルミ粉、マイカ粉などのメタリック意匠顔料の単体またはそれらを組み合わせて用いることができる。
【００１４】
着色塗膜３の着色樹脂塗料に関して、塗料本質１００重量部に対する防虫剤の配合量を0.３〜3.０重量部としたのは、防虫剤の配合量が0.３重量部未満であると、紫外線によって防虫剤が劣化して害虫忌避効果の持続性を十分に期待できない。一方、3.０重量部を超えると、焼付け乾燥後の着色塗膜３の光沢が鈍くなるうえ、平滑で均一な厚みの塗膜を形成するのが困難となり、防虫剤の使用量が多くなる分だけ製造コストが高く付くからである。上記の趣旨より、防虫剤の配合量は、0.５〜1.０重量部にすることがより好ましい。
【００１５】
着色塗膜３の乾燥膜厚を5.０〜４０μｍとしたのは、これが5.０μｍ未満であると、着色塗膜３の着色隠蔽性が十分でなく、下層が透けて見えたり、紫外線の透過を防止するに不十分となる。一方、着色塗膜３の乾燥膜厚が４０μｍを超えると、ワキや泡立ちといった塗工段階での問題を生じて塗装作業を円滑に行うことが困難になるうえ、二次製品をプレス成形する際に着色塗膜３が剥離するなど着色塗膜３の加工性が損なわれるからである。上記の趣旨より、着色塗膜３の乾燥膜厚は、7.０〜３０μｍにすることがより好ましい。
【００１６】
着色塗膜３の形成に際し、塗料本質１００重量部に対して紫外線吸収剤が1.０〜5.０重量部配合されていると、太陽光線や紫外線の透過による防虫剤の紫外線劣化や着色塗膜３の光沢低下を防止することができる。紫外線吸収剤の配合量を先の1.０〜5.０重量部としたのは、1.０重量部未満であると防虫剤の劣化や光沢低下の防止効果が十分に期待できず、5.０重量部を超えると塗膜の耐汚染性、加工性、塗膜外観などが悪化し、紫外線吸収剤による着色塗膜３の黄変が観察され、かつ紫外線吸収剤の使用量増加による製造コスト高を招くからである。
【００１７】
前記紫外線吸収剤としては、大気雰囲気中、昇温速度５℃／分の加熱条件下において、３００℃で１０質量％以下の重量減少となるトリアジン系紫外線吸収剤またはベンゾトリアゾール系紫外線吸収剤が単独又は複合で含まれているものが、用いて好適である。とくにトリアジン系紫外線吸収剤が最適である。塗膜焼付け条件が板温１８０〜２６０℃に達したときに、一般に使用されているベンゾフェノン系、シアノアクリレート系の紫外線吸収剤では耐熱性に劣るため、塗膜中に含まれる紫外線吸収剤が昇華して減少するからである。
【００１８】
防虫剤が、二塩基酸飽和ジアルキルエステルよりなる化合物と、合成ピレスロイド系化合物との配合剤からなるときは、着色樹脂塗料に対する相溶性と熱安定性とが優れているため、着色塗膜３の焼付け時における防虫剤の熱分解を防止でき、薬効が高く確実な害虫忌避効果を発揮する。害虫忌避効果を相乗的に向上できる点でも有利である。また、焼付け乾燥工程における防虫剤の熱分解や変質が解消するので、より高い温度の乾燥熱で着色塗膜３の乾燥が行える。従って、連続製造ライン上において、乾燥処理時の母材鋼板１の送給速度を低下させる必要がなく、塗装鋼板を能率よく製造することができる。
【００１９】
【発明の作用効果】
本発明では、トップ層の着色塗膜３に防虫剤が分散配合されており、着色塗膜３の着色顔料で紫外線等の透過を遮って防虫剤の分解をよく防止する。従って、着色塗膜３の存在で必要最小限の意匠性を付与したうえで、害虫忌避効果の長期持続性を確保できる。
【００２０】
着色塗膜３の着色樹脂塗料に関して、塗料本質１００重量部に対して防虫剤が0.３〜3.０重量部配合されているとともに、紫外線吸収剤が1.０〜5.０重量部配合されていると、紫外線による防虫剤の防虫機能の劣化を更に有効に抑制できるので、害虫忌避効果の長期持続性に更に有利なものとなる。
【００２１】
請求項４記載の紫外線吸収剤および請求項５記載の防虫剤を選択することにより、着色塗膜３の焼付け乾燥時における紫外線吸収剤および防虫剤の熱分解（変質）を最低限に抑制できる。プライマー２が存在する場合にでも、２コート２ベークで済むため、生産効率も良くなる。
【００２２】
【発明の実施の形態】
図１および図２に示すように、表面にクロメート処理がされた板厚0.４５mmの亜鉛めっき鋼板（めっき付着量が両面で９０ｇ／m2）からなる母材鋼板１の片面に、ポリエステル系塗料をロールコータで塗布して板温２１０℃で３０秒間焼付け、乾燥膜厚3.０μｍのプライマー２を形成した（図２（ａ））。続いて、プライマー２の表面に、白色顔料を含むポリエステル系の着色樹脂塗料をロールコータで塗布して２３０℃で４０秒間焼付け、乾燥膜厚２０μｍの着色塗膜３をトップ層として形成することにより、防虫塗装鋼板をつくった（図２（ｂ））。
【００２３】
（実施例１）先の着色塗膜３を形成するに際し、ビヒクルおよび白色顔料からなる塗料本質１００重量部に対して防虫剤を0.３重量部配合した着色樹脂塗料を用いた。その防虫剤としては、二塩基酸飽和ジアルキルエステルよりなる化合物と、合成ピレスロイド系化合物との配合剤を用いた。
【００２４】
（実施例２）先の着色塗膜３を形成するに際し、塗料本質１００重量部に対して実施例１の防虫剤を0.５重量部配合してなる着色樹脂塗料を用いた以外は、実施例１と同様にして防虫塗装鋼板をつくった。
【００２５】
（実施例３）先の着色塗膜３を形成するに際し、塗料本質１００重量部に対して実施例１の防虫剤を1.０重量部配合してなる着色樹脂塗料を用いた以外は、実施例１と同様にして防虫塗装鋼板をつくった。
【００２６】
（実施例４）先の着色塗膜３を形成するに際し、塗料本質１００重量部に対して実施例１の防虫剤0.３重量部に加えて、トリアジン系紫外線吸収剤およびベンゾトリアゾール系紫外線吸収剤を2.０重量部配合してなる着色樹脂塗料を用いた以外は、実施例１と同様にして防虫塗装鋼板をつくった。
【００２７】
（実施例５）先の着色塗膜３を形成するに際し、塗料本質１００重量部に対して実施例１の防虫剤0.５重量部に加えて、実施例４の紫外線吸収剤を2.０重量部配合してなる着色樹脂塗料を用いた以外は、実施例１と同様にして防虫塗装鋼板をつくった。
【００２８】
（実施例６）先の着色塗膜３を形成するに際し、塗料本質１００重量部に対して実施例１の防虫剤1.０重量部に加えて、実施例４の紫外線吸収剤を2.０重量部配合してなる着色樹脂塗料を用いた以外は、実施例１と同様にして防虫塗装鋼板をつくった。
【００２９】
（比較例１）母材鋼板１にプライマー２ついで着色塗膜３を実施例１と同様にして２コート２ベーク方式で形成したのち、着色塗膜３の表面にポリエステル系のクリア樹脂塗料（着色顔料を含まず）を塗布し、２２０℃で４０秒間焼付けてクリア塗膜をトップ層として形成した。但し、着色塗膜３には、防虫剤および紫外線吸収剤が一切含まれていない。その代わり、クリア塗膜の形成に際し、クリア樹脂塗料にはこれの１００重量部に対して実施例１と同じ防虫剤を0.３重量部配合して、防虫塗装鋼板をつくった。
【００３０】
（比較例２）先のクリア塗膜の形成に際し、クリア樹脂塗料にはこれの１００重量部に対して防虫剤を0.５重量部配合した以外は、比較例１と同様にして防虫塗装鋼板をつくった。
【００３１】
（比較例３）先のクリア塗膜の形成に際し、クリア樹脂塗料にはこれの１００重量部に対して防虫剤を1.０重量部配合した以外は、比較例１と同様にして防虫塗装鋼板をつくった。
【００３２】
（比較例４）先のクリア塗膜の形成に際し、クリア樹脂塗料にはこれの１００重量部に対して防虫剤0.３重量部に加えて、実施例１と同じ紫外線吸収剤を2.０重量部配合した以外は、比較例１と同様にして防虫塗装鋼板をつくった。
【００３３】
（比較例５）先のクリア塗膜の形成に際し、クリア樹脂塗料にはこれの１００重量部に対して防虫剤0.５重量部に加えて、紫外線吸収剤を2.０重量部配合した以外は、比較例１と同様にして防虫塗装鋼板をつくった。
【００３４】
（比較例６）先のクリア塗膜の形成に際し、クリア樹脂塗料にはこれの１００重量部に対して防虫剤1.０重量部に加えて、紫外線吸収剤を２重量部配合した以外は、比較例１と同様にして防虫塗装鋼板をつくった。
【００３５】
（試験例１）かくして、実施例１〜６の防虫塗装鋼板から順に６種類の試験片１〜６を切り出した。また、比較例１〜６の防虫塗装鋼板から順に６種類の試験片７〜１２を切り出した。
【００３６】
防虫塗装鋼板の薬効を確認するために、上記１２種類の試験片（以下、符号２３で示す）を用いて害虫忌避効果の確認試験をした。試験に際しては、図３に示すように、高さ２０cm、縦１５cm、横２６cmの、内面に樹脂コーティングが施された紙製の容器２０を用意し、この容器２０内に先の試験片で構成した供試シェルター２１と、比較のための対照シェルター２２とを配置した。
【００３７】
供試シェルター２１は、辺長７cmの正方形の試験片２３と、試験片２３と同形同大のベニヤ板製のカバー２４と、カバー２４の四周辺に固定したスペーサ２５とで構成し、試験片２３とカバー２４とが５mmの隙間を介して対向し、四周辺のそれぞれに出入口２６が開口する形態にした。
【００３８】
対照シェルター２２は、基本的に供試シェルター２１と同様の構造とするが、試験片２３に代えてベニヤ板製の底板２７を用いた点が異なる。容器２０内の両シェルター２１・２２の間には、水を含浸させた脱脂綿２８と飼料２９とを配置し、供試虫（チャバネゴキブリの成虫）が自由に餌を摂取できるようにした。
【００３９】
上記の試験準備が整った状態で、２０匹の供試虫を容器２０内に放して、２４時間後に各シェルター２１・２２内に入り込んでいる供試虫の数をカウントした。また、ＳＷＯＭ（サンシャインウエザオメーター）により紫外線を照射し、１００時間後、および２００時間後の各シェルター２１・２２内の供試虫の数をそれぞれカウントした。周囲の温度や湿度などの環境条件の違いや、個体差によるばらつきを考慮して、試験はそれぞれ二度繰り返した。得られた供試シェルター２１内の供試虫の数の合計値と、対照シェルター２２内の供試虫の数の合計値との比の逆数から百分率を算出して害虫の忌避率とした。なお、供試シェルター２１内の供試虫の数の合計値が、対照シェルター２２内の供試虫の数の合計値を越えた場合には、害虫忌避効果は無いものとして、忌避率は０％とした。
【００４０】
表１は２４時間経過後における各試験片での試験結果を示す。
【００４１】
【表１】

【００４２】
この表１の合計値に明らかなとおり、試験片１〜１２では、防虫剤の配合量に比例して忌避率が向上していた。
【００４３】
表２はＳＷＯＭ照射下での１００時間経過後における試験片での試験結果を示す。
【００４４】
【表２】

【００４５】
この表２に示すとおり、トップ層の着色塗膜に防虫剤を含む本発明実施例の試験片（１〜６）は、トップ層のクリア塗膜に防虫剤を含有する比較例の試験片（７〜１２）よりも、高い忌避率を維持していた。また、紫外線吸収剤を配合した試験片（４〜６、１０〜１２）は、これを配合していない試験片（１〜３、７〜９）よりも、それぞれよい結果を示している。
【００４６】
表３はＳＷＯＭ照射下での２００時間経過後における各試験片での試験結果を示す。
【００４７】
【表３】

【００４８】
この表３に示すとおり、比較例の試験片（７〜１２）は、ほとんどがその防虫機能を失っているのに比べて、本発明実施例の試験片（１〜６）は、機能を発揮し続けている。なかでも、紫外線吸収剤を配合した本発明実施例の試験片（４〜６）は、これを配合していない試験片（１〜３）に比べて有利性がいっそう明確に現れる結果となった。
【００４９】
（試験例２）着色樹脂塗料に対する防虫剤の配合量を変更した場合の、防虫塗装鋼板の物性や外観状態等を評価するために、５種類の試験片（１３〜１７）を用意して試験を行った。試験片１３〜１７の構成は、防虫剤の配合量を除いて、実施例１の試験片１と同様である。試験片１３〜１７では、着色塗膜３を形成するポリエステル系の着色樹脂塗料において、塗料本質１００重量部に対する防虫剤の配合量をそれぞれ1.０、2.０、3.０、3.５、4.０重量部と変化させた。
【００５０】
表４は、上記の５種類の試験片（１３〜１７）の物性及び外観等の比較評価を示す。外観評価は、ロールコータで着色樹脂塗料を塗工して着色塗膜３を形成した場合の塗膜の外観を目視判定し、その塗装作業性を併せて確認した。加工性を確認するために、各試験片１３〜１７は、１８０度折り曲げることにより、塗膜の剥離の有無を目視によって確認した。各試験片は３％塩酸水溶液に２４時間浸漬して耐酸性を試験した。同様に、各試験片は３％水酸化ナトリウム水溶液に２４時間浸漬して、耐アルカリ性を試験した。
【００５１】
【表４】

【００５２】
この表４から判るように、防虫剤の配合量が3.０重量部以下の各試験片１３〜１６は、塗装作業時およびプレス作業時の加工性になんら問題がなく、耐酸性や耐アルカリ性にも優れていた。しかし、防虫剤の前記配合量を4.０重量部とした試験片１７では、塗装時に筋やかすれを生じるうえ、これを１８０度折り曲げた場合には塗膜の剥離がみられた。さらに塩酸水溶液によって塗膜の一部が剥離され、水酸化ナトリウム水溶液によって塗膜の一部に膨れを生じた。これらの結果から、着色樹脂塗料としては、防虫性能をも考慮すると塗料本体１００重量部に対して防虫剤を0.３〜3.０重量部配合すれば良いことが確認できた。
【図面の簡単な説明】
【図１】防虫塗装鋼板の断面図である。
【図２】防虫塗装鋼板の製造手順を示す断面図である。
【図３】防虫塗装鋼板の試験具の平面図とシェルターの斜視図である。
【符号の説明】
１母材鋼板
２プライマー
３着色塗膜[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a coated steel sheet having an insect repellent function.
[0002]
[Prior art]
It is known from Patent Document 1 that a pest control agent is added to paints applied to wooden parts, metal parts and furniture used for floors and building structures in general homes to repel pests in the homes. It is.
[0003]
[Patent Document 1]
Japanese Patent Laid-Open No. 11-35405 [0004]
[Problems to be solved by the invention]
As for the coated steel sheet in which the coating material containing the insect repellent is applied to the base steel sheet, the insecticidal agent distributed on the surface exhibits the medicinal effect. Therefore, the present applicant has proposed an insect-proof coated steel sheet that can enhance its medicinal effect while suppressing the use of the insect-repellent to a smaller amount (Japanese Patent Application No. 2001-326658). There, a colored coating film was formed on a base steel plate, and then a clear coating film containing an insect repellent was formed on the surface as a top layer.
[0005]
However, this insect-proof coated steel plate exhibits an insect-proof function effectively at the beginning of production, but the insect-proof function decreases with time. Originally, insect repellents are easily decomposed by light energy such as ultraviolet rays. This is because the insect-repelling agent is blended with the clear coating film so that not only the surface layer portion of the clear coating film but also the insect-repelling agent dispersed in the deep layer portion is decomposed at an early stage by the transmission of ultraviolet rays.
[0006]
The present inventor has found that when an insect repellent is added to the colored coating film (enamel layer), the pest repellent effect is sustained for a long time. The insect repellent dispersed in the surface layer is easily decomposed by ultraviolet rays, but the insect repellent dispersed in the colored coating film is difficult to decompose because the irradiation of ultraviolet rays is hindered by the color pigment. In actual use, even if the outer surface of the colored coating film collapses or is missing, the insect repellent inside the layer protrudes to the surface, so that the pest repellent effect will be advantageously exhibited.
[0007]
The present invention has been proposed based on such findings. An object of the present invention is to obtain an insect-proof coated steel sheet that can be expected to have a long-lasting pest repellent effect.
[0008]
[Means for Solving the Problems]
As shown in FIG. 1, the insect-coated steel sheet of the present invention is an insect-coated steel sheet in which a colored coating 3 is applied and formed as a top layer on the surface of a base steel plate 1. It is formed of a colored resin paint containing 0.3 to 3.0 parts by weight of an insect repellent with respect to 100 parts by weight of the paint essence, and the dry film thickness of the colored coating film 3 is 5.0 to 40 μm. It is characterized by being set.
[0009]
The base material steel plate 1 of the present invention is not particularly limited, and for example, a galvanized steel plate, a zinc-aluminum alloy plated steel plate, an aluminum plated steel plate, a stainless steel plate, an aluminum plate and the like can be used. A chromium-based or non-chromium-based chemical conversion treatment layer (chromate treatment) is previously formed on the outer surface of the base steel plate.
[0010]
In the insect-proof coated steel sheet of the present invention, the coating film structure is not particularly limited as long as the colored coating film 3 is in the top layer, but in order to improve the corrosion resistance and coating film adhesion of the base steel sheet 1, FIG. As shown in FIG. 2, it is desirable to apply and form a chromium-based or non-chromium-based primer 2 on the surface of the base steel plate 1 subjected to the above-described treatment. The dry film thickness of the primer 2 can be set to about 2.0 to 10 μm, preferably about 3.0 to 7.0 μm from the viewpoints of coating film adhesion, corrosion resistance, workability, cost, and the like.
[0011]
Next, after the primer 2 is painted and baked on the surface of the base steel plate 1, a colored resin paint in which 0.3 to 3.0 parts by weight of the insect repellent is uniformly dispersed and applied to 100 parts by weight of the paint is applied, Baking is performed at a baking plate temperature of 180 to 260 ° C. to form a colored coating film 3 having a dry film thickness of 5.0 to 40 μm.
[0012]
The colored resin paint for forming the colored coating film 3 is for a known precoat, such as an epoxy resin paint, an epoxy-urethane resin paint, a polyester resin paint, an acrylic resin paint, a fluorine resin paint, etc. Various auxiliaries such as aggregates, leveling agents and matting agents are added to the essence of paints composed of vehicles and colored pigments in order to impart film hardness, scratch resistance and other properties. . In addition, efficacy enhancers, antioxidants, plasticizers, surfactants, antibacterial agents, fungicides and the like can be used in combination as necessary.
[0013]
In the colored resin paint, the essence of the paint contains 1.0 to 20% by weight of a color pigment in order to impart design properties and prevent deterioration of the insect repellent due to ultraviolet rays. As the coloring pigment, a known inorganic coloring pigment and metallic design pigments such as aluminum powder and mica powder can be used alone or in combination.
[0014]
Regarding the colored resin paint of the colored coating film 3, the amount of the insect repellent is 0.3 to 3.0 parts by weight with respect to 100 parts by weight of the essence of the paint because the amount of the insect repellent is less than 0.3 parts by weight. If the insect repellent is deteriorated by the ultraviolet rays, the sustainability of the insect repellent effect cannot be sufficiently expected. On the other hand, if it exceeds 3.0 parts by weight, the gloss of the colored coating film 3 after baking and drying becomes dull, and it becomes difficult to form a coating film having a smooth and uniform thickness, and the amount of insect repellent used is increased. This is because the manufacturing cost increases by the amount. In view of the above, it is more preferable that the amount of the insect repellent is 0.5 to 1.0 part by weight.
[0015]
The reason why the dry film thickness of the colored coating film 3 is set to 5.0 to 40 μm is that if it is less than 5.0 μm, the colored coating film 3 has insufficient color concealment, and the lower layer can be seen through, Insufficient to prevent transmission. On the other hand, if the dry film thickness of the colored coating film 3 exceeds 40 μm, it will cause problems in the coating stage such as wrinkles and foaming, and it will be difficult to carry out the painting work smoothly, and when the secondary product is press-molded. This is because the workability of the colored coating film 3 is impaired, for example, the colored coating film 3 is peeled off. In view of the above, it is more preferable that the dry film thickness of the colored coating film 3 is 7.0 to 30 μm.
[0016]
When forming the colored coating film 3, if 1.0 to 5.0 parts by weight of the ultraviolet absorber is blended with 100 parts by weight of the coating material, the deterioration of the insecticide due to the transmission of sunlight or ultraviolet rays or the colored coating The gloss reduction of the film 3 can be prevented. If the amount of the UV absorber is 1.0 to 5.0 parts by weight, if it is less than 1.0 part by weight, the effect of preventing the deterioration of the insect repellent and the decrease in gloss cannot be sufficiently expected. If the amount exceeds 0.0 part by weight, the stain resistance, processability, and coating film appearance of the coating film deteriorate, yellowing of the colored coating film 3 due to the UV absorber is observed, and the production is increased due to an increase in the amount of UV absorber used. This is because the cost increases.
[0017]
As the ultraviolet absorber, a triazine-based ultraviolet absorber or a benzotriazole-based ultraviolet absorber, which reduces the weight by 10% by mass or less at 300 ° C. under heating conditions of 5 ° C./min in the air atmosphere, is used alone. Alternatively, those contained in a composite are suitable for use. Triazine-based UV absorbers are particularly optimal. When the film baking conditions reach a plate temperature of 180 to 260 ° C., generally used benzophenone-based and cyanoacrylate-based UV absorbers have poor heat resistance, so the UV absorber contained in the coating film sublimates. This is because it decreases.
[0018]
When the insect repellent is composed of a compound of a compound composed of a dibasic acid saturated dialkyl ester and a synthetic pyrethroid compound, the compatibility with the colored resin paint and the thermal stability are excellent. It can prevent thermal decomposition of insect repellents during baking, and has a high medicinal effect and reliable pest repellent effect. It is also advantageous in that the pest repellent effect can be synergistically improved. Moreover, since the thermal decomposition and alteration of the insect repellent are eliminated in the baking and drying step, the colored coating film 3 can be dried with higher heat of drying. Therefore, on the continuous production line, it is not necessary to reduce the feeding speed of the base steel plate 1 during the drying process, and the coated steel plate can be efficiently manufactured.
[0019]
[Effects of the invention]
In the present invention, an insect repellent is dispersed and blended in the colored coating 3 of the top layer, and the color pigment of the colored coating 3 blocks the transmission of ultraviolet rays and the like to prevent decomposition of the insect repellent. Therefore, the long-term sustainability of the insect repellent effect can be ensured while providing the minimum necessary design properties due to the presence of the colored coating film 3.
[0020]
With respect to the colored resin coating of the colored coating film 3, 0.3 to 3.0 parts by weight of the insect repellent is blended with 100 parts by weight of the essence of the paint, and 1.0 to 5.0 parts by weight of the ultraviolet absorber is blended. If it is done, deterioration of the insect repellent function of the insect repellent due to ultraviolet rays can be more effectively suppressed, which is further advantageous for long-term persistence of the insect repellent effect.
[0021]
By selecting the ultraviolet absorbent according to claim 4 and the insect repellent according to claim 5, thermal decomposition (degeneration) of the ultraviolet absorbent and the insect repellent during baking and drying of the colored coating film 3 can be minimized. Even when the primer 2 is present, the production efficiency is improved because two coats and two bake suffice.
[0022]
DETAILED DESCRIPTION OF THE INVENTION
As shown in FIGS. 1 and 2, a polyester-based paint is applied on one side of a base steel plate 1 made of a galvanized steel plate having a chromate treatment and a thickness of 0.45 mm (plating adhesion amount is 90 g / m 2 on both sides). Was applied with a roll coater and baked at 210 ° C. for 30 seconds to form a primer 2 having a dry film thickness of 3.0 μm (FIG. 2A). Subsequently, a polyester-based colored resin paint containing a white pigment is applied to the surface of the primer 2 with a roll coater and baked at 230 ° C. for 40 seconds to form a colored coating film 3 having a dry film thickness of 20 μm as a top layer. Insect-proof steel plates were made (FIG. 2 (b)).
[0023]
(Example 1) In forming the colored coating 3, the colored resin coating was used in which 0.3 parts by weight of an insect repellent was blended with 100 parts by weight of the coating material essence consisting of a vehicle and a white pigment. As the insect repellent, a compounding agent of a compound composed of a dibasic acid saturated dialkyl ester and a synthetic pyrethroid compound was used.
[0024]
(Example 2) When forming the above-mentioned colored coating film 3, it implemented except having used the colored resin coating material which mix | blended 0.5 weight part of insect repellents of Example 1 with respect to 100 weight part of coating material essence. An insect-proof coated steel plate was made in the same manner as in Example 1.
[0025]
(Example 3) When the colored coating film 3 was formed, the procedure was carried out except that a colored resin paint obtained by blending 1.0 part by weight of the insect repellent of Example 1 with respect to 100 parts by weight of the paint essence was used. An insect-proof coated steel plate was made in the same manner as in Example 1.
[0026]
(Example 4) In forming the colored coating film 3, in addition to 0.3 parts by weight of the insect repellent of Example 1 with respect to 100 parts by weight of the coating material, triazine-based UV absorber and benzotriazole-based UV absorption An insect-proof coated steel sheet was produced in the same manner as in Example 1 except that a colored resin paint containing 2.0 parts by weight of the agent was used.
[0027]
(Example 5) In forming the colored coating 3, the ultraviolet absorber of Example 4 was added to 0.5 parts by weight of the insect repellent of Example 1 with respect to 100 parts by weight of the coating material. An insect-proof coated steel sheet was produced in the same manner as in Example 1 except that the colored resin paint mixed with parts by weight was used.
[0028]
(Example 6) When forming the above-mentioned colored coating film 3, in addition to 1.0 part by weight of the insect repellent of Example 1 with respect to 100 parts by weight of the coating material, the UV absorber of Example 4 is 2.0. An insect-proof coated steel sheet was produced in the same manner as in Example 1 except that the colored resin paint mixed with parts by weight was used.
[0029]
(Comparative Example 1) A primer 2 and a colored coating film 3 were formed on the base steel plate 1 in the same manner as in Example 1 by the 2-coat 2-bake method, and then a polyester-based clear resin paint (colored) was formed on the surface of the colored coating film 3 A clear coating film was formed as a top layer by baking at 220 ° C. for 40 seconds. However, the colored coating film 3 does not contain any insect repellents or ultraviolet absorbers. Instead, when forming the clear coating film, 0.3 parts by weight of the same insect repellent as in Example 1 was blended with 100 parts by weight of the clear resin paint to make an insect-proof coated steel sheet.
[0030]
(Comparative Example 2) Insect-proof coated steel sheet in the same manner as in Comparative Example 1 except that 0.5 parts by weight of an insect repellent was added to 100 parts by weight of the clear resin paint when the clear coating film was formed. Made.
[0031]
(Comparative Example 3) Insect-proof coated steel sheet in the same manner as in Comparative Example 1 except that 1.0 part by weight of an insect repellent was added to 100 parts by weight of the clear resin paint when forming the previous clear coating film. Made.
[0032]
(Comparative Example 4) In forming the above clear coating film, in addition to 0.3 parts by weight of the insect repellent to 100 parts by weight of the clear resin coating, the same ultraviolet absorber as in Example 1 was 2.0. An insect-proof coated steel sheet was prepared in the same manner as in Comparative Example 1 except that the blended parts by weight were used.
[0033]
(Comparative Example 5) In forming the clear coating film, the clear resin paint was blended with 2.0 parts by weight of an ultraviolet absorber in addition to 0.5 parts by weight of an insect repellent with respect to 100 parts by weight of the clear resin paint. Made an insect-proof coated steel plate in the same manner as in Comparative Example 1.
[0034]
(Comparative Example 6) In forming the previous clear coating film, in addition to 1.0 part by weight of the insect repellent and 100 parts by weight of the clear resin paint, 2 parts by weight of the ultraviolet absorber was blended. An insect-proof coated steel plate was produced in the same manner as in Comparative Example 1.
[0035]
(Test Example 1) Thus, six types of test pieces 1 to 6 were cut out in order from the insect-proof coated steel plates of Examples 1 to 6. Moreover, six types of test pieces 7 to 12 were cut out in order from the insect-proof coated steel plates of Comparative Examples 1 to 6.
[0036]
In order to confirm the medicinal effect of the insect-proof coated steel sheet, a test for confirming the insect repellent effect was performed using the above-mentioned 12 kinds of test pieces (hereinafter denoted by reference numeral 23). In the test, as shown in FIG. 3, a paper container 20 having a height of 20 cm, a length of 15 cm, and a width of 26 cm and having an inner surface coated with a resin coating is prepared. A test shelter 21 and a control shelter 22 for comparison were placed.
[0037]
The test shelter 21 is composed of a square test piece 23 having a side length of 7 cm, a cover 24 made of plywood having the same shape and size as the test piece 23, and spacers 25 fixed around the four sides of the cover 24. 23 and the cover 24 are opposed to each other with a gap of 5 mm, and the entrance / exit 26 is opened in each of the four periphery.
[0038]
The control shelter 22 has basically the same structure as the test shelter 21 except that a veneer bottom plate 27 is used instead of the test piece 23. Absorbent cotton 28 impregnated with water and feed 29 were placed between the

shelters

21 and 22 in the container 20 so that the test insects (gerb cockroach adults) could freely feed.
[0039]
20 test insects were released into the container 20 in the state where the above test preparation was completed, and the number of test insects entering the

shelters

21 and 22 was counted after 24 hours. Further, ultraviolet rays were irradiated by a SWOM (Sunshine Weather Omometer), and the number of test insects in each of the

shelters

21 and 22 after 100 hours and 200 hours was counted. The test was repeated twice, taking into account differences in environmental conditions such as ambient temperature and humidity, and variations due to individual differences. The percentage was calculated from the reciprocal of the ratio between the total number of test insects in the obtained test shelter 21 and the total number of test insects in the control shelter 22, and was used as the pest repellent rate. When the total number of test insects in the test shelter 21 exceeds the total number of test insects in the control shelter 22, it is assumed that there is no pest repellent effect and the repelling rate is 0. %.
[0040]
Table 1 shows the test results of each test piece after 24 hours.
[0041]
[Table 1]

[0042]
As is apparent from the total values in Table 1, the repellent rate was improved in the test pieces 1 to 12 in proportion to the amount of the insect repellent.
[0043]
Table 2 shows the test results of the test pieces after 100 hours have passed under SWOM irradiation.
[0044]
[Table 2]

[0045]
As shown in Table 2, the test pieces (1 to 6) of the examples of the present invention containing the insect repellent in the colored coating film of the top layer are the test pieces of the comparative example containing the insect repellent in the clear paint film of the top layer ( It maintained a higher repellent rate than 7-12). Moreover, the test piece (4-6, 10-12) which mix | blended the ultraviolet absorber has shown the result respectively better than the test piece (1-3, 7-9) which has not mix | blended this.
[0046]
Table 3 shows the test results of each test piece after 200 hours under SWOM irradiation.
[0047]
[Table 3]

[0048]
As shown in Table 3, the test pieces (7 to 12) of the comparative examples show the function as compared with the test pieces (1 to 6) of the examples of the present invention, compared with the case where most of the test pieces (7 to 12) have lost their insect repellent function. I keep doing it. Especially, the test piece (4-6) of the Example of this invention which mix | blended the ultraviolet absorber became a result in which an advantage appears more clearly compared with the test piece (1-3) which is not mix | blended this. .
[0049]
(Test Example 2) Five types of test pieces (13 to 17) were prepared and tested in order to evaluate the physical properties and appearance of the insect-proof coated steel sheet when the amount of the insect-repellent agent was changed with respect to the colored resin paint. Went. The configurations of the test pieces 13 to 17 are the same as those of the test piece 1 of Example 1 except for the amount of the insect repellent. In the test pieces 13 to 17, in the polyester-based colored resin paint forming the colored coating film 3, the blending amounts of the insect repellent with respect to 100 parts by weight of the paint essence are 1.0, 2.0, 3.0, 3.5 , And 4.0 parts by weight.
[0050]
Table 4 shows comparative evaluations such as physical properties and appearance of the above five types of test pieces (13 to 17). Appearance evaluation visually checked the appearance of the coating film when the colored coating film 3 was formed by applying a colored resin paint with a roll coater, and the coating workability was also confirmed. In order to confirm the workability, each of the test pieces 13 to 17 was visually checked for peeling of the coating film by bending 180 degrees. Each test piece was immersed in a 3% aqueous hydrochloric acid solution for 24 hours to test acid resistance. Similarly, each test piece was immersed in a 3% aqueous sodium hydroxide solution for 24 hours to test the alkali resistance.
[0051]
[Table 4]

[0052]
As can be seen from Table 4, each of the test pieces 13 to 16 having an insect repellent content of 3.0 parts by weight or less has no problem in workability at the time of painting and pressing, and has acid resistance and alkali resistance. It was also excellent. However, in the test piece 17 in which the blending amount of the insect repellent was 4.0 parts by weight, streaks and fading were generated during coating, and when this was bent 180 degrees, peeling of the coating film was observed. Furthermore, a part of the coating film was peeled off by the aqueous hydrochloric acid solution, and a part of the coating film was swollen by the aqueous sodium hydroxide solution. From these results, it was confirmed that as the colored resin paint, it is sufficient to add 0.3 to 3.0 parts by weight of an insect repellent to 100 parts by weight of the paint main body in consideration of insect repellent performance.
[Brief description of the drawings]
FIG. 1 is a cross-sectional view of an insect-proof coated steel sheet.
FIG. 2 is a cross-sectional view showing a procedure for manufacturing an insect-proof coated steel sheet.
FIG. 3 is a plan view of an insect-proof coated steel sheet test device and a perspective view of a shelter.
[Explanation of symbols]
1 Base material steel plate 2 Primer 3 Colored coating

Claims

An insect-proof coated steel plate in which a colored coating film 3 is applied and formed as a top layer on the surface of the base material steel plate 1,
Is colored coating 3, as well as formulation 0.3 to 3.0 parts by weight of insecticide on the paint essentially 100 parts by weight of colored pigment is contained 1.0 to 20% by weight, 1. UV absorber 0 ~ 5. It is formed with a colored resin paint blended with 5.0 parts by weight ,
An insect-proof coated steel sheet in which the dry film thickness of the colored coating film 3 is set to 5.0 to 40 μm.

The base steel plate 1 is coated with a primer 2 and then a colored coating 3.
The insect-resistant coated steel sheet according to claim 1, wherein the dry film thickness of the primer 2 is set to 2.0 to 10 μm.

The insect-resistant coated steel sheet according to claim 1 , wherein the ultraviolet absorber is a triazine ultraviolet absorber and / or a benzotriazole ultraviolet absorber .

The insect repellent coated steel sheet according to claim 1 , wherein the insect repellent comprises a compounding agent of a compound comprising a dibasic acid saturated dialkyl ester and a synthetic pyrethroid compound .