JP4344055B2 - Mirror surface decorative plate manufacturing method - Google Patents

Description

【００２２】
Ｒａ（０．８）は、０．８ｍｍ以下の波長成分を示して、さらにＲａ（２．５）は２．５ｍｍ以下の波長成分を示すこととなる。かくして、本発明で規定した△Ｒａ（２．５-０．８）は、Ｒａ（２．５）とＲａ（０．８）の差を示し、波長０．８ｍｍ付近〜２．５μｍ付近の粗さ成分を間接的に示すものである。
【００２３】
本発明の製造方法に使用される無機質基板は、耐熱性、不燃性でありまた容易に入手できる等の観点から、繊維補強珪酸カルシウム成形体、繊維補強セメント成形体、繊維補強セラミックス成形体、軽量気泡コンクリート（ALC）、ガラス、タイル、石材、およびこれらの複合材が例示できる。
【００２４】
必要に応じて、これら無機質基板の表層には、基板補強樹脂塗料が用いられる。基板補強樹脂塗料は、基板への含浸性が良好で、十分な基板強度を発揮させることができ、しかも多くの無機質基板が有するアルカリ成分によっても侵されないものであるが、特にこれに限定されるものではない。該塗料は、溶剤系または水系であることができ、含まれる樹脂としては、ウレタン樹脂、エポキシ樹脂、アクリル樹脂等が好ましい。基板補強樹脂塗料の塗布量は、使用する基板、使用する樹脂、粘度等により異なり、特に制限されないが、例えば、かさ比重が１．０前後の珪酸カルシウム板に湿気硬化型ウレタン系の基板補強樹脂塗料を塗布する場合には、５０ｇ／ｍ²〜２００ｇ／ｍ²程度の塗布量が好ましい。５０ｇ／ｍ²より少なければ、基板補強が不十分であり、また、２００ｇ／ｍ²より多い場合には、珪酸カルシウム板表面に樹脂膜を形成してしまい、後述する金属箔との接着の際、接着剤が一部基板に浸透して接着強度を増大させるアンカー効果が期待できず、接着強度が低下させてしまうことになる。この基板補強樹脂塗料の塗布方法は、公知の方法を採用することができる。例えば、ロールコーター、フローコーター、エアースプレー、エアレススプレー等の塗工機が用いられる。さらに、無機質基板への含浸および生産性を上げるために、予め無機質基板表面を加熱するのがよい。同様に、塗布後において、硬化時間を短縮するために加熱してもよい。
【００２５】
本発明の製造方法において、接着剤層の形成のために使用される接着剤は、従来から公知のものを用いることができる。例えば、熱硬化性樹脂系接着剤では、ユリア系、メラミン系、レゾルシノール系、フェノール系、エポキシ系、ポリウレタン系、ポリアロマチック系、ポリエステル系等が挙げられ、また、熱可塑性樹脂系接着剤では、酢酸ビニル系、ポリビニルアルコール系、ポリビニルアセタール系、アクリル系、ポリエチレン系、セルロース系等が挙げられる。また、エストラマー系では、クロロプレンゴム系、ニトリルゴム系、SBR系、SBS-SIS系、ポリサルファド系、ブチルゴム系、シリコーンゴム系等が挙げられる。また、極力、耐熱性や難燃性にすぐれた接着剤を使用することが好ましいことから無機系接着剤の使用も好ましい。また、固化および硬化方法では室温硬化形、熱硬化形、ホットメルト形、感圧形、再湿形等が好適に使用できる。さらに、接着剤の形態では、水溶液形、溶剤形、エマルジョン形、固形（特にフィルム状）、テープ形等が好適に使用できる。
【００２６】
接着剤の塗布量は、接着剤層の厚さが２０μｍ〜２００μｍ、好ましくは５０μｍ〜１５０μｍとなるような量がよい。接着剤層の厚さが２０μｍ未満の場合には、接着剤を均一に塗布することが困難であり、しかも、無機質基板の凹凸が、後述の所定の方法で金属箔を接着しても、金属箔上に凹凸が生じて好ましくない。また、２００μｍを超える場合には、経済的に好ましくない。
【００２７】
接着剤の塗工方法については、金属箔接着後の表面の粗さ曲線を小さくするような接着剤および接着剤の塗布方法、および接着方法が用いられる。最も好ましい塗工方法としては、フローコーター、ナイフコーター、ドクターナイフコーター、ダイコーターを用いた方法が、接着剤を均一に塗布することができて好ましい。ロールコーター、エアースプレー、エアレススプレー等の塗工機を用いた塗工方法は、塗着面を平滑に仕上げることが困難であるが、後述の接着方法を用いれば採用可能である。
【００２８】
本発明の製造方法で使用される金属箔は、目的に応じて適宜選択できるが、極力硬質なものが好ましい。すなわち、厚さ０．０５ｍｍ〜０．５ｍｍ、好ましくは０．１ｍｍ〜０．５ｍｍのアルミニウム箔またはステンレス箔がよい。厚さがこの範囲のアルミニウム箔またはステンレス箔であると、無機質基板や接着剤層に起因する凹凸が残存し難く、最終製品において良好な鏡面性が得られる。また、経済性、耐久性、加工性等の観点からも好ましい。なお銅箔も使用可能である。また、金属箔の△Ｒａ（２．５-０．８）は、０．１５μｍ以下、好ましくは０．１０μｍ以下、より好ましくは０．０６μｍ以下がよい。この条件を満たす金属箔は、例えば、ＪＩＳ Ｇ４３０５「冷間圧延ステンレス鋼板および鋼帯.６表面仕上げ」に規定する表面仕上げ（仕上げ記号、No.2D、No.2B、No.３、No.４、＃２４０、＃320、＃400、BA、HL）により表面処理を行ったものが挙げられる。なお、前記表面仕上げを超える艶消し処理や凹凸模様を加えたものについては、使用が好ましくない。さらに、亜鉛メッキ鋼板のように、表面に亜鉛の結晶が通常の凝固過程において生成し、スパングルをもつものに対しては、その表面形状の△Ｒａ（２．５-０．８）が０．５μｍ程度あるため、使用が好ましくない。
【００２９】
次に、無機質基板と金属箔とを接着剤により接着するが、接着後の金属箔の表面も、△Ｒａ（２．５-０．８）が０．１５μｍ以下、好ましくは０．１０μｍ以下、より好ましくは０．０６μｍ以下であるのがよい。０．１５μｍを超えると、最終製品の表面形状において十分な平滑面が得られず、結果的に優れた鏡面性は得られ難い。
【００３０】
このような接着方法としては、無機質基板および金属箔層に圧力を面圧として加えられるスチールベルトプレス法や多段プレス法が用いられる。図1は、スチールベルトプレス法を説明するための図である。スチールベルトプレス機１は、１対のスチールベルト１１および１２がローラー１３、１３および１４、１４の回りをそれぞれ巻回している構造を主要部として有している。ロール状に巻かれた金属箔２１は、ガイドローラー３１、３２を経てダイコーター等の塗工機４１によりその表面に接着剤をコーティングされ、さらにガイドローラー３３、３４、３５、３６を経てスチールベルト１１および１２間に送り込まれ、同時に、進んできた無機質基板５１と接着される。両者の接着は、加圧ローラー６１、６１・・・および６１'、６１’・・・により加圧されながら行われ、ローラー１３、１４によるものではない。即ち、ローラー１３、１４部分におけるスチールベルト１１と１２間の間隔は、基板の厚さと金属箔の厚さの和より大きくする必要がある。無機質基板５１と金属箔２１は、スチールベルト１１の回転に応じて加圧されながら移動し、接着が完了した後は、カッター７１により所望の大きさに切断される。スチールベルトプレス法は、無機質基板の送り速度を調整するか、或いはスチールベルトの長さを調整するかして、加圧時間の調整を行うことができ、更にスチールベルトを加熱することにより、接着剤の硬化を促進させることも可能である。なお、スチールベルトプレス法による生産性を良好にするためには、加圧時間を短くするのが望ましく、そのため接着剤として、例えば、二液硬化ウレタン系やホットメルト系、エストラマー系の接着剤を採用するのが好ましい。ホットメルト系接着剤を用いる場合には、加熱温度が１００℃〜１５０℃、加圧時間は、１分〜２分程度が好ましい。
【００３１】
図2は、多段プレス法を説明するための図である。多段プレス機２は、図2（ａ）で示すようにプレス用金型８１、８２、および複数枚のプレス用中間板８３から構成されている。プレス用金型８１、８２とプレス用中間板８３との間、またはプレス用中間板の間に、無機質基板５１と金属箔２１とを接着剤を介して積層して設置し、続いて図2（ｂ）で示すようにプレス用金型８１および８２間に圧力を加えるものである。なお、多段プレス法の場合も、スチールベルトプレス法と同様な接着剤が好適に用いられる。多段プレス法における加圧時間は、装置の大小にかかわらず調整が可能である。しかしながら、多段プレス法はバッチ式であるため生産効率はスチールベルトプレス法に比べて劣る。
【００３２】
スチールベルトプレス法および多段プレス法による接着圧力としては、十分な接着強度発現と接着後の平滑性を確保するため、５０ｋＰａ〜１０００ｋＰａ程度が必要である。５０ｋＰａより小さい場合は十分な接着強度が得られず、１０００ｋＰａより大きい場合は、金属箔上の△Ｒａ（２．５-０．８）の差が０．１５μｍより大きくなりやすい。
【００３３】
一方、圧力が線圧として加えられるロールプレス方式や無機質基板と金属箔との間の空気を吸引して接着する真空プレス方式による場合には、金属箔表面に無機質基板および接着剤層に起因する凹凸が生じ易く結果的に△Ｒａ（２．５-０．８）が０．１５μｍより大きくなりやすい。
【００３４】
次に、金属箔上に化粧層が形成される。化粧層は、塗膜層または印刷層の単層あるいは塗膜層と印刷層の複層からなり、塗膜層は、次工程において行われる印刷に関連して、金属箔の色の隠蔽、印刷柄の意匠性の向上、印刷層の密着性の向上等を目的として設けられる。
【００３５】
塗膜層の表面形状は、△Ｒａ（２．５-０．８）が０．１５μｍ以下、好ましくは０．１０μｍ以下、より好ましくは０．０６μｍ以下がよい。そのために、塗膜層は、透明な塗料や顔料を加えた塗料を、フローコーターにより塗布して形成するのが好ましい。スプレーコーターを使用した場合には、ゆず肌に代表されるような比較的大きな形状を生成しやすく、最終製品において、鏡面性が低下してしまう。また、ロールコーターを使用した場合には、塗膜面に「ロール目」に代表されるような凹凸が生成し、同様に好ましくない。顔料を使用する場合には、その粒径が、その塗膜表面形状の△Ｒａ（２．５-０．８）が０．１５μｍ以下、好ましくは０．１０μｍ以下、より好ましくは０．０６μｍ以下を満足できるような大きさであれば特に制限はされない。使用できる樹脂、硬化方法についても、先の条件を満たすものであれば特に制限はない。塗膜層用の樹脂は、それに求められる性能を満足できるものであれば、特に制限されることはない。ポリエステル樹脂、アミノ樹脂、エポキシ樹脂、ポリウレタン樹脂、アクリル樹脂等を例示することができ、また、塗膜層の柄に対応した着色を施すための、顔料や染料を加えたものが、好適に使用できる。硬化方法については、常温硬化、熱硬化、紫外線硬化、電子線硬化等の方法を例示できるが、特に、紫外線硬化や電子線硬化の方法の場合には、塗膜層表面に凹凸が生じ難く、特に好ましい。また、塗膜層の厚みについては、先の塗膜層の性能を満足すれば、何ら制限はない。しかしながら、実質上、１０μｍより薄いと、金属箔色を隠蔽することが難しく、また２００μｍより厚い場合は、経済上好ましくない。
【００３６】
金属箔上または塗膜層上に印刷層を設ける方法としては、公知の印刷方法が利用できる。即ち、例えば、転写印刷、グラビア印刷、スクリーン印刷、オフセット印刷また、インクジェットプリンターを用いて化粧柄を形成する方法が好ましい。
【００３７】
しかしながら、印刷層については、その表面形状が△Ｒａ（２．５-０．８）が０．１５μｍ以下、好ましくは０．１０μｍ以下、より好ましくは０．０６μｍ以下である必要がある。△Ｒａ（２．５-０．８）が０．１５μｍを超えると、透明または半透明紫外線硬化樹脂層からなるトップコート層を形成した後の鏡面性が著しく低下する。なお、転写箔を利用して印刷する場合には、転写箔自身のインキ層表面の△Ｒａ（２．５-０．８）が０．１５μｍ以下、好ましくは０．１０μｍ以下、より好ましくは０．０６μｍ以下がよい。これ以上の△Ｒａ（２．５-０．８）を持つ転写箔を利用して印刷した場合には、当然の如く印刷層の△Ｒａ（２．５-０．８）が０．１５μｍより大きくなる。
【００３８】
なお、予め金属箔層と印刷層とからなる積層体、または、予め金属箔層、塗膜層および印刷層が順次積層されてなる積層体を、先に示したスチールベルトプレス法や多段プレス法で無機質基板上に所定の圧力で接着してもよい。この場合も、積層体上の表面形状は、△Ｒａ（２．５-０．８）が０．１５μｍ以下、好ましくは０．１０μｍ以下、より好ましくは０．０６μｍ以下である。
【００３９】
本発明の製造方法でトップコート層を形成するために使用される透明または半透明樹脂塗料は、従来公知の樹脂塗料であることができ、またその硬化方法も特に制限されない。しかしながら、塗料中の溶剤が物理的に蒸発することによって塗膜が形成されるようなラッカータイプ、例えばニトロセルロース誘導体、塩化ビニル樹脂、アクリル樹脂、ビニルアセタール樹脂、塩素化ゴム等は、いずれも塗料中の揮発分が蒸発して塗膜を形成するものであり、溶剤の蒸発速度が速いほど早く乾燥塗膜になるが、塗膜面に凹凸を生じる場合があり、その選定や乾燥条件には注意を要する。
【００４０】
そこで、溶剤を全く含まない若しくは含有量が極端に少ない、紫外線硬化樹脂または電子線硬化樹脂が本発明の製造方法では採用される。透明または半透明樹脂塗料を紫外線または電子線によって硬化させる場合は、樹脂が縮合または付加反応により硬化するときに大きなエネルギーを受けており、一般的に架橋密度が高く、硬度が増し、耐洗浄性に優れるため、また非常に硬化時間が短いために生産性に優れる等の利点がある。
【００４１】
本発明の製造方法に使用できる紫外線硬化型塗料は、塗膜特性の優れた透明塗膜或いは半透明塗膜を形成することができる塗料であれば好ましく使用できる。紫外線硬化型塗料は、反応性共重合体、光重合性化合物、光重合性開始剤を必須成分として含有し、必要に応じて、着色剤塗料用添加剤を添加して得られる。例えば、反応性共重合体には、アルキド樹脂、ポリエステル樹脂、アクリル樹脂、ポリウレタン樹脂、エポキシ樹脂等が主に挙げられる。また、光重合性化合物（重合性モノマー）は、不飽和ポリエステルやスチレン等が挙げられる。また、光重合性開始剤としては、カルボニル化合物、有機過酸化物、アゾ化合物、ハロゲン化物、硫黄化合物等が主に使用できる。
【００４２】
電子線硬化樹脂により形成される透明塗膜または半透明塗膜は、電子線の照射によって架橋、重合しうる樹脂からなる。この方法で硬化された樹脂は紫外線硬化型樹脂と異なり、紫外線による変色、劣化が少なく、製品が屋外にも使用できるという利点を持つ。同樹脂は、アクリル樹脂、ポリエステル樹脂、エポキシ樹脂、アミノ樹脂（メラミン樹脂など）、ポリアミド樹脂、ウレタン樹脂等の飽和結合を骨格とする官能基含有基体、それら官能基と付加或いは重合しうる基を有するビニル系単量体よりなり、必要により、反応性希釈剤或いは架橋性オリゴマーを加えることができる。該ビニル系単量体としては、アクリル酸、メタクリル酸、アリルアルコール、無水マレイン酸、メチロールアクリルアミド、メタクリルアミド、アクリル酸ヒドロキシルエチル、メタクリル酸ヒドロキシルエチル、アクリル酸グリシジル、アミノアルキル、メタクリル酸アミノアルキル等がある。また、反応性希釈剤としては、アクリル酸エステル類、メタクリル酸エステル類、アクリロニトリル、メタクリロニトリル、スチレン、α-メチルスチレン等がある。また、架橋性オリゴマーとしては、２〜４個の重合性ビニル基を有する分子量１０００以下の化合物が挙げられ、ジアリルフタレート、エチレングリコールメタアクリレート、テトラエチレングリコールジ（メタ）アクリレート、ビス-（エチレングリコールフタレート）ジ（メタ）アクリレート、ビス-（ジエチレングリコールフタレート）ジ（メタ）アクリレーと、ポリエチレングリコールジ（メタ）アクリレート、ポリプロピレングリコールジ（メタ）メタアクリレート等がある。
【００４３】
透明または半透明樹脂層表面のＲａ（２．５）は、０．１５μｍ以下であり、好ましくは０．１０μｍ以下、より好ましくは０．０６μｍ以下である。０．１５μｍより大きい場合、光沢、鮮映性等の低下により鏡面性が劣ってしまう。このような、表面形状を形成させる方法として、フローコーターが用いられる。スプレーコーターを使用する場合には、ゆず肌に代表されるような比較的大きな形状を生成しやすく、塗膜面に入射する光の正反射方向が変化して、結果的に鏡面性が低下してしまう。また、ロールコーターを使用した場合には、塗膜面に「ロール目」に代表されるような凹凸が生成し易い。更に、近年、ＵＶ透明または半透明フィルムをロールプレスにより接着後、ＵＶ照射により硬化させる方法もあるが、この方法についても、ロールコーターと同様に塗膜面に凹凸が生じ易い。
【００４４】
また、塗布量は、トップコート層である透明または半透明樹脂層の厚みが、２０μｍより大きく２００μｍ以下になるような塗布量がよく、例えば、２０ｇ／ｍ²〜２５０ｇ／ｍ²程度が好ましい。塗料塗布後のレベリングを利用し、平滑面を得るために、塗布量は多ければ多い程よい。そのため塗膜厚さは、２０μｍより大きいことが望ましい。しかしながら、こうした紫外線を利用した硬化方法は、紫外線が進入できる塗膜厚さでなければならないので、その塗膜厚みは２００μｍ以下が好ましい。なお、本発明の製造方法でいう「透明または半透明」とは、全光線透過率７０〜１００％を意味する。
【００４５】
【実施例】
以下、本発明の製造方法を実施例および比較例により説明するが、本発明の方法はこの実施例によりなんら制限を受けるものではない。各層の表面粗さ（Ｒａ）は、ＪＩＳ Ｂ０６０１付属書に従って測定した。なお、金属箔層、塗膜層、印刷層については作成途中で測定した。測定条件を表２に示す。
【００４６】
【表２】
Ｒａ カットオフ（ｍｍ） 評価長さ（ｍｍ）
Ｒａ（０．８） ０．８ ８
Ｒａ（２．５） ２．５ ８
【００４７】
実施例１
まず、予め研磨紙番手120で研磨をした珪酸カルシウム板（(株)アスク製、商品名セルストン、厚み６ｍｍ）に、ロールコーターにより、湿気硬化型ウレタンシーラー（(株)トウペ製、商品名トアASシーラー）を１００ｇ／ｍ²塗布し、２４時間室内に放置後、積み重ねて、2週間さらに室内に放置養生した。次に、厚さ０．１ｍｍのステンレス箔（川崎製鉄(株)製、SUS304 BA仕上げ）裏面に、ダイコーターによりホットメルト系接着剤を１００ｇ／ｍ²（武田薬品工業(株)製）を塗布し、塗布後３０秒間放置後、プレス圧力が３００ｋＰａのスチールベルトプレス法により珪酸カルシウム板と接着を行った。この金属箔層を有する基板を、１００℃に調節した乾燥機中に５分間放置し、金属箔表面を５０℃程度にした後、フローコーターにより塗膜層用塗料（日本ペイント(株)製、商品名ルリール310／溶剤ウレタン系）を塗布し、１００℃に調節した乾燥機中で５分間焼き付けを行い、厚さ３０μｍの塗膜層を形成した。次に、転写箔（大日本印刷(株)自然石柄）をゴム硬度７０、ロール温度２００℃、送り速度３ｍ／分の条件で、熱ロール転写を行い、印刷層を形成した。次いで、印刷層上にフローコーターを用いて、紫外線硬化型塗料（日本ペイント(株)製、商品名ＡＦ１クリア）８０ｇ／ｍ²を塗布した。２分間室内で静置させた後、紫外線を照射し硬化させ、トップコート層（透明または半透明樹脂層）を形成させた。
【００４８】
実施例２
実施例１と同様に、珪酸カルシウム板にシーラーを塗布、養生を行った。次に、厚さ０．１ｍｍのステンレス箔（川崎製鉄(株)製、SUS304 No.4仕上げ）裏面および珪酸カルシウム板表面に、合成ゴム系接着剤（コニシ(株)製、商品名ボンドＧシリーズ）を各１００ｇ／ｍ²ずつエアースプレーにて塗布した。塗布後１分間放置した後、ステンレス箔と珪酸カルシウム板を接着し、ハンドロールで軽くプレスを行った後、プレス圧力３００ｋＰａ、加圧時間６０分の条件で多段プレスを行い、ステンレス箔と珪酸カルシウム板を接着した。次いで、化粧層とトップコート層を実施例１と同様の方法で形成した。
【００４９】
実施例３
実施例１と同様に、珪酸カルシウム板にシーラーを塗布、養生、更に金属箔と珪酸カルシウム板を接着した。塗膜層は、形成しなかった。次に、転写箔（凸版印刷(株)製の自然石柄）をゴム硬度７０、ロール温度２００℃、送り速度３ｍ／分の条件で、熱ロール転写を行い、印刷層を形成した。ついで、トップコート層を実施例１と同様の方法で形成させた。
【００５０】
実施例４
実施例２と同様に、珪酸カルシウム板にシーラーを塗布、養生、更に金属箔と珪酸カルシウム板を接着した。なお金属箔には０．１ｍｍ厚のアルミニウム箔（東海アルミ箔(株)製）を使用した。塗膜層、印刷層、トップコート層については、実施例１と同様に行った。
【００５１】
比較例１
実施例１と同様に、珪酸カルシウム板にシーラーを塗布、養生を行った。次に、実施例４と同様のアルミ箔裏面に、アクリルウレタン系エマルジョン型接着剤（コニシ(株)製、商品名ＣＶＣシリーズ）８０ｇ／ｍ²をロールコーターにて塗布した。さらに、プレス圧力３００ｋＰａ、温度１１０℃、圧締時間3分の条件において真空プレス方式により、アルミ箔と珪酸カルシウム板を接着した。塗膜層、印刷層、トップコート層については、実施例１と同様に行った。
【００５２】
比較例２
実施例１と同様に、塗膜層形成まで行った。次に、ロール転写により転写箔（和信化学工業(株)製の大理石柄）をゴム硬度７０、ロール温度２００℃、材料送り速度３ｍ／分の条件で、転写柄を印刷し、印刷層を形成した。次いで、実施例１と同様のトップコート層を形成した。
【００５３】
比較例３
実施例１と同様に印刷層形成まで行った。次いで、ＵＶ透明または半透明フィルム（日本ペイント(株)製）をゴム硬度７０、ロール温度２００℃、材料送り速度３ｍ／分の条件で、ロールプレスにより接着後、ＵＶ照射により硬化させ、トップコート層を形成させた。
【００５４】
比較例４
実施例２と同様に、珪酸カルシウム板にシーラーを塗布、養生、更に金属箔と珪酸カルシウム板を接着した。尚、金属箔には０．１ｍｍ厚の溶融亜鉛メッキ鋼板（川崎製鉄(株)製、レギラースパングル）を使用した。塗膜層、印刷層、トップコート層については、実施例１と同様に行った。
【００５５】
比較例５
予め研磨紙番手１２０で研磨を行った珪酸カルシウム板（(株)アスク製、商品名セルストン６ｍｍ）を使用した。この基板を１００℃雰囲気中に５分程度放置した後、ロールコーターにより、湿気硬化型ウレタンシーラー（日本ペイント(株)製、商品名Ｕ−６０）を６０ｇ／ｍ²塗布した。その後、紫外線硬化型塗料（日本ペイント(株)製、商品名ユービコート６０サンディングシーラー）６０ｇ／ｍ²を、ロールコーターおよびナチュラルリバースコーターにより塗布し、次いで紫外線を照射し、硬化させた。その直後に、研磨紙番手１８０により研磨を行った。次いで、焼き付け型ウレタン塗料（日本ペイント(株)製、商品名ルリール３１０）１１０ｇ／ｍ²をフローコーターにより塗布し、１００℃雰囲気中で５分間焼き付けを行った。ロール転写以降の処理については、実施例１と同様に行った。
【００５６】
実施例および比較例で作製した試験体について、各層のＲａ（２．５）、Ｒａ（０．８）およびΔＲａ（２．５-０．８）を表３に示す。表３から、実施例の化粧板は、トップコート層下の表面形状のΔＲａ（２．５-０．８）が比較例に比べて小さく、トップコート層上のＲａ（２．５）も小さくなり、結果的に鏡面性に優れることが分かる。
【００５７】
【表３】

【００５８】
【発明の効果】
本発明の製造方法によれば、不燃性、耐熱性、耐洗浄性を兼ね備え、さらに意匠性、特に鏡面性に優れた化粧板を提供することができる。特に、本発明の製造方法は、このような化粧板を従来の化粧板と同等の加工性、作業量を保持しながら、高い生産性で提供できるものである。本発明の製造方法により得られる化粧板は、特に台所のガスコンロ周辺部に配置されるキッチンパネルに好適に使用される。
【図面の簡単な説明】
【図1】 スチールベルトプレス法を説明するための図である。
【図2】 多段プレス法を説明するための図である。
【符号の説明】
1 スチールベルトプレス機
１１，１２ スチールベルト
１３，１４ ローラー
２１ 金属箔
３１，３２，３３，３４，３５，３６ ガイドローラー
５１ 無機質基板
６１，６１’ 加圧ローラー
７１ カッター
８１，８２ プレス用金型
８３ プレス用中間板[0001]
BACKGROUND OF THE INVENTION
  The present invention is excellent in specularity, and,The present invention relates to a method for producing a specular decorative board excellent in fire resistance, nonflammability, workability and the like.
[0002]
[Prior art]
  Traditionally, tiles have excellent non-flammability, high hardness, durability, heat resistance, and washing resistance.ofA lot has been used around the stove. However, cement joint materials, which are porous materials, are usually used for tile joints.BecauseIn particularDifficult to cleanMolds are easy to breedwon. Therefore,TilesLong termofUsedWhenThere is a disadvantage that it is very inferior in terms of cleanlinessWas. Furthermore, in terms of design, the original aesthetics of the tiles were maintained, but the design variations were lacking. Even on the processed surface, there are drawbacks such as difficulty in cutting, so it is difficult to unitize,Long constructionThe construction cost was required and the cost of the tile itself was high, resulting in a high total cost.
[0003]
  In addition, decorative plates made of metal foil such as stainless steel bonded to calcium silicate plates or wood-based materials are also used, but scratches are very conspicuous when using mirror-like stainless steel, so the surface is intentionallyofGloss is reduced by polishing, etc., and it is noticeable even if scratches etc. occurDifficultWas. However, by applying such treatment, the specularity is naturally reduced and oil stains are removed.AriseIt was easy.
[0004]
  AboveproblemTo solveTo shorten the work period and improve the processability of the decorative boardAs,cementsystemOf plates and calcium silicate plateslikeInorganic substrateTheThe decorative board used has been proposed. And such a decorative board has easy cleaning from the performance side.,Dirt is removed from the appearance of peopleChiMirror surface, high design and workabilityButNow,Such a decorative boardThe following means are adopted.
[0005]
  (1) Substrate polishing process
  An inorganic substrate mainly composed of a calcium silicate plate or a cement-based plate having a bulk specific gravity of around 1.0 is considerably inferior in surface smoothness as compared with a resin plate, wood, and wood-based plate material. For this reason, when using such a material as a substrate for specularity, some method is used.ThanThe smoothness of the substrate surface must be improved. As a typical example, the surface of these inorganic substrates is polished (polishing paper count # 120 or higher). However, lightweight aggregates such as pearlite with a particle size of several tens to 1000 μm are used in the substrate.ingIn some cases, by performing a polishing process, these aggregates come off and cause recesses, and,Smoothness occurs when polishing is performed by generating loopholes in reinforcing fibers such as glass fiber.ButWorseningShiIf you end upButis there. Therefore, inorganic and organic or organic-inorganic such as cementsystemA polishing process may be performed after applying a composite hole filling material.
[0006]
  (2) Substrate surface sealer treatment
  Inorganic substrates mainly composed of calcium silicate plates and cement-based plates are generally weak and weak in surface strength. Therefore, a sealer is usually used for the purpose of reinforcing the substrate surface. As these sealers, epoxy type, urethane type solvent type or water type impregnation type is generally used. Usually for industrial coatings,These sealersofBefore and after application, jet heater, infrared dryer, etc.ofHeat treatment is performed by a dryer, improving the impregnation of the sealer, curing timeofShortenIs plannedYes.
[0007]
  (3) Sealing treatment and base coat treatment
  Inorganic substrates mainly composed of calcium silicate plates and cement-based platesOn the decorative boardWhen usingIn order to give specularity, only the processing of (1) and (2)Surface smoothnessButIt is still insufficient. Therefore, smoothness is further improvedfor, (2)ofA sealing treatment is performed on the treated surface. Usually, a reactive resin containing solid content such as calcium carbonate filler and fiber is cured by heat curing, ultraviolet curing, electron beam curing, etc., and then the surface is polished with high count (# 180 or higher) The surface smoothness is improved. Further, a base coat layer is formed on this layer for stopping alkali from the substrate, durability, and concealing the base color. However, a substrate with relatively good surface smoothness is used.YouWhen using a coating machine such as a flow coater, apply more than one coating directly on the sealer treated surface by applying the leveling properties of the coating itself.Shi, Forming a thick base coat layerdo itIn some cases, the closing process is omitted. For base coat layerpaintIn general, a urethane resin system is preferably used. As with the substrate reinforcing sealer, as an industrial coating, this plate material is heated before and after coating in order to shorten the curing time.NeedThere is a case.
[0008]
  (4) Makeup layer formation
  Various methods are known for imparting high design properties to a decorative board. In recent years, printing such as transfer printing, screen printing, and direct printing, and sputter coating are often performed directly on the base coat.
[0009]
  (5) Topcoat layer formation
  A transparent or translucent resin layer is formed on the surface of the decorative board for the purpose of further improving the performance and design of the decorative board itself, including surface hardness, durability, and washing resistance. As a general forming method, the decorative board surface after forming the decorative layer is heated in a dryer such as a jet heater or an infrared dryer, and an ultraviolet reaction curable resin or electron beam is applied by a coating machine such as a flow coater. Application of reaction curing resinShiThen, by leaving it for several minutes in a dryer adjusted to around 50 ° C,Using the leveling properties of the paint itself, the paint surface is finished smoothly and the resin is cured by irradiating with ultraviolet rays or electron beams.TheFinishIs a thing. UV reaction curing resinpaintAlternatively, instead of applying an electron beam reaction curable resin coating, transfer a film of an ultraviolet reaction curable resin or an electron beam reaction curable resin coating, and then cure the resin by irradiating with ultraviolet rays or an electron beam.TheSometimes finished.
[0010]
  Other conventional techniques include, for example, a decorative board (specialized) used for furniture in which an intermediate coating resin layer, a decorative sheet, and decorative paper are bonded to a wooden board via an aluminum foil and an ultraviolet coating layer is provided on the surface. No. 2-175240), a composite panel obtained by joining a resin film laminated metal panel and an inorganic panel (Japanese Patent Laid-Open No. 5-33190), a nonflammable or flame-retardant material such as a fluororesin film and a metal foil A decorative sheet (JP-A-10-109386) obtained by pasting a decorative sheet formed by combining a sheet substrate to the surface of an inorganic base plate, a fiber-mixed slag cement plate, a metal plate, and a fluororesin film on the surface A kitchen panel (JP-A-9-125562) having a printed pattern on the back surface of a fluororesin film or the surface of a metal plate, a base plate material, metal foil, a cosmetic agent, and purple A decorative board made of a linear curable resin, which is a urethane-acrylate oligomer ultraviolet curable resin having a coating layer of 7 to 20 μm and a pencil hardness of 7H or more. -216308) and the like.
[0011]
  However, the decorative board obtained by the above prior art has the following drawbacks. That is, (1) Regarding the polishing process of the substrate, the inorganic substrate itself is very uneven and the distribution of the voids is uneven.ThereforeSince it cannot be made smooth, there are limitations on the substrates that can be used. Moreover, in order to solve such a problem, a hole filling material was required, which led to high costs. Regarding the sealing treatment and base coat treatment of (3), solid content such as fillers such as calcium carbonate filler and reinforcing fibersManyThe included reactive resin is cured by a method such as heat curing, ultraviolet curing, or electron beam curing. However, in any curing method, the temperature of the resin layer increases immediately after curing, and the thickness is particularly large. When processing a relatively thin substrate of several millimetersInThe substrate is warped, plus a resin layerofSince the thickness is as thin as several tens to 100 μm, troubles such as unpolishing and overpolishing easily occur in the subsequent polishing step. In other words, shrinkage due to temperature changes of the substrate surface resin layer and dimensional changes due to changes in the moisture content of the substrate are complicatedly related.TogetherTherefore, it is very difficult to manage “warp” during the manufacturing process, resulting in defects such as unpolished and overpolished.GoodsWas supposed to produce a lot. Furthermore, in order to increase the specularity, in this layer,HighIt is necessary to have a smooth finish, and it is necessary to make the abrasive paper count very high. In order to perform high count polishing, it is necessary to perform rough polishing to fine polishing multiple times in order.WhatProductivity is poor and equipment costsButQuite necessaryNaThe Furthermore, when performing fine polishing, the abrasive paper for fine polishing is very exhausted.TheTherefore, the running cost is also increased. However, even if such very laborious work is performed, the final product is never satisfactory in terms of specularity.
[0012]
  Also,The specularity of the decorative board disclosed in the above-mentioned JP-A-2-175240, JP-A-5-33190, JP-A-10-109386, JP-A-9-125562, JP-A-9-216308, etc. There is still room for improvementIs a thing.
[0013]
[Problems to be solved by the invention]
  Therefore,The object of the present invention is that the mirror surface is more excellent than the conventional decorative board, and also excellent in fire resistance, incombustibility, workability, etc.TheIt is providing the manufacturing method of a specular decorative board.
[0014]
[Means for Solving the Problems]
  The inventors,As a result of intensive research, it was found that the above conventional problems were solved. That is,The present invention provides an inorganic substrate with an adhesive layer, a metal foil layer,Consists of coating layer or printing layer or coating layer and printing layerMakeup layer, andTop coatLayers in this orderInLayeredSpecularityVeneerManufacturing methodInAdhesive is applied to the surface of the inorganic substrate and / or the back surface of the metal foil, and the inorganic substrate and the metal foil are bonded to each other by applying a surface pressure of 50 kPa to 1000 kPa by a steel belt press method or a multistage press method. By forming an adhesive layer and a metal foil layer and providing a decorative layer on the metal foil layer, thisA step of reducing the difference between the center line average roughness when the cut-off of the decorative layer surface is 2.5 mm and the center line average roughness when the cut-off is 0.8 mm to 0.15 μm or less; and on the surface of the decorative layer A transparent or translucent UV or electron beam curable resin coating is applied by a flow coater and cured to provide a transparent or translucent topcoat layer, so that the surface of the topcoat layer has a cutoff of 2.5 mm. A center line average roughness of 0.15 μm or less.In addition, the step of reducing the difference between the center line average roughness when the cut-off of the surface of the decorative layer is 2.5 mm and the center line average roughness when the cut-off is 0.8 mm is 0.15 μm or less on the metal foil in advance. A decorative layer is provided to form a laminate, and an adhesive is applied to the surface of the inorganic substrate and / or the back surface of the metal foil of the laminate, and the inorganic substrate and the laminate are 50 kPa to 1000 kPa by a steel belt press method or a multistage press method. It is also possible to perform adhesion by applying a surface pressure of 2 and providing an adhesive layer, a metal foil layer and a decorative layer on the inorganic substrate. In addition,The metal foil is preferably an aluminum foil or a stainless steel foil.
[0015]
  by the way,The specularity is, for example,,Contrast when images of fluorescent lamps are projected on the surface of decorative panelsGDoes not drop, and the image is clearSurface shapeIndicateIs a thing. That is, it can be said that both smoothness and gloss are generic. MoritaAuthor(Smoothing of the plane by painting and appearance / surface technology vol.40, No.1,1989)InIn terms of human appearance sensation expression and surface shape (surface roughness), when the roughness components of the irregularities (waves) forming the surface shape are classified by wavelength, short wavelength components of several tens of μm or less are mainly glossy. In addition, the medium wavelength component of several tens of μm to several hundreds of μm gives a sense of magnifying and mud, and further gives the human sense of distortion of an image in which a long wavelength component of several hundred μm to several mm is reflected.ing.
[0016]
  AndThe present inventors have a wavelength component whose wavelength is 2.5 mm or less.One ofThe centerline average roughness (hereinafter referred to as Ra (2.5)) when the cutoff value is 2.5 mm, which is a characteristic value, is closely related to the surface smoothness indicating the specularity, and the value is 0.15 μm. In the following, it has been found that excellent specularity can be exhibited when the thickness is preferably 0.10 μm or less, more preferably 0.06 μm or less.
[0017]
  Accordingly, the present inventors have prepared a decorative board having nonflammability and workability, and having a decorative surface Ra (2.5) of 0.15 μm or less, preferably 0.10 μm or less, more preferably 0.06 μm or less. As a result of earnest research to develop, as a result of laminating a metal foil layer having a specific roughness curve on the surface of an inorganic substrate mainly made of calcium silicate plate or cement-based plate,,The metal foil layer has a specific roughness curve on the surfacemake upLayer, and transparent or translucent resin layer with a specific roughness curve on itA topcoat layer consisting ofSequential formationShiThe specular decorative sheet is found to be excellent in design, cleaning resistance, processability, and productivity, and in particular, in terms of specularity, making the present invention.ToIt was.
[0018]
  Specifically, the present inventionManufacturing methodThe features ofmake upFocus on a specific wavelength component on the layer surface and limit this componentTo doThat is,This makeupThe difference in centerline average roughness (Ra) between the layer surface cut-off of 2.5 mm and the cut-off of 0.8 mm (hereinafter referred to as ΔRa (2.5-0.8)) is 0.15 μm or less ( Provided according to the metal foil layerConsists only of the coating layer△ Ra (2.5-0.8) for the decorative layerIs set to 0.15 μm)ByTransparent or translucent resin layerOf the topcoat layerThe surface Ra (2.5) can be reduced to 0.15 μm or less. The present inventionManufacturing methodAccording to Morita pointed out the long wavelength component of several hundred μm to several mm,SpecialIn addition, the shape of the wavelength of 500 μm to 2000 μm, which greatly affects the specularity, can be reduced on the surface of the substrate, and the workability and work equivalent to those of a conventional decorative board can be achieved.amountA mirror-finished decorative board can be obtained with high productivity while maintaining the above.
[0019]
DETAILED DESCRIPTION OF THE INVENTION
  The definitions of the centerline average roughness (Ra) and the cutoff value in the present invention are defined in JISB0601. For example, the cutoff value is described as follows.
・ Cutoff value
  In the instrument that directly reads the surface roughness parameter, the long wavelength component was removed from the wavelength component obtained by Fourier analysis of the cross section curve without using the reference length in order to remove the high wavelength component of the surface irregularities. Think about things. The limit wavelength for removing the long wavelength component is the cutoff value. Note that the reference length means the length of a portion of a cross-sectional curve (a contour that appears at the cut end when a measured object is cut in a plane perpendicular to the measured surface).
[0020]
  The roughness component distribution by wavelength is extremely different from the wavelength of the selected cutoff value.SeparationAs long as the component amount is small at a wavelength near the cutoff value, there is no difference in Ra regardless of which cutoff value is selected. However, if the distribution of roughness components by wavelength is non-uniformly present in the wavelength range of several selected cutoff values, the surface roughness of Ra naturally varies depending on the selected cutoff value. For example, when a wavelength component of about several tens of μm dominates like a stainless steel plate, there is no significant difference between Ra (0.8) and Ra (2.5). On the other hand, in the case where a relatively large zinc crystal is precipitated on the surface of the steel sheet, such as hot dip galvanized steel sheet foil, there is a large difference between Ra (0.8) and Ra (2.5). . Table 1 shows typical Ra and different stainless steel foils and galvanized steel sheet foils.
[0021]
[Table 1]

[0022]
  Ra (0.8) indicates a wavelength component of 0.8 mm or less, and Ra (2.5) indicates a wavelength component of 2.5 mm or less.ThusΔRa (2.5-0.8) defined in the present invention indicates a difference between Ra (2.5) and Ra (0.8), and has a roughness around a wavelength of 0.8 mm to 2.5 μm. Indirectly indicate ingredientsIs a thing.
[0023]
  The present inventionManufacturing methodThe inorganic substrate used in the above is heat-resistant, non-flammable and easily available, and is made of fiber-reinforced calcium silicate molded body, fiber-reinforced cement molded body, fiber-reinforced ceramic molded body, lightweight cellular concrete (ALC) , Glass, tile, stone,And thisThese composite materials can be exemplified.
[0024]
  If necessary, a substrate reinforcing resin paint is used for the surface layer of these inorganic substrates. Substrate-reinforced resin paint has good substrate impregnation and exhibits sufficient substrate strengthTo letIt can be, and is not affected by the alkali component of many inorganic substrates,SpecialInto thisLimitedIsIt is not something. The paint can be solvent-based or water-based, and the resin contained therein is preferably a urethane resin, an epoxy resin, an acrylic resin, or the like. The coating amount of the substrate reinforcing resin coating varies depending on the substrate used, the resin used, the viscosity, etc., and is not particularly limited.,When applying moisture-curable urethane-based substrate-reinforced resin paint to a calcium silicate plate with a bulk specific gravity of around 1.0InIs 50 g / m²~ 200g / m²A coating amount of about is preferred. 50 g / m²If it is less, the substrate reinforcement is insufficient, and,200 g / m²MoreNoCaseInWill form a resin film on the calcium silicate plate surface,StateWhen adhering to metal foil, the adhesive cannot be expected to have an anchor effect that penetrates the substrate and increases the adhesive strength, resulting in a decrease in adhesive strength.LetEnd upWill be.thisA well-known method can be employ | adopted for the coating method of a board | substrate reinforcement resin coating material. For example, a coating machine such as a roll coater, flow coater, air spray, airless spray, or the like is used. Furthermore, in order to improve the impregnation and productivity of the inorganic substrate, the inorganic substrate surface is heated in advance.To doGood. Similarly, shorten the curing time after application.forYou may heat.
[0025]
  The present inventionIn the manufacturing method ofA conventionally well-known thing can be used for the adhesive agent used for formation of an adhesive bond layer. Examples of thermosetting resin adhesives include urea, melamine, resorcinol, phenol, epoxy, polyurethane, polyaromatic, and polyester, and thermoplastic resin adhesives. , Vinyl acetate, polyvinyl alcohol, polyvinyl acetal, acrylic, polyethylene, and cellulose. Examples of elastomers include chloroprene rubber, nitrile rubber, SBR, SBS-SIS, polysulfad, butyl rubber, and silicone rubber. In addition, since it is preferable to use an adhesive having excellent heat resistance and flame retardancy as much as possible, use of an inorganic adhesive is also preferable. Also, solidification and curing methods include room temperature curing type, thermosetting type, hot melt type, pressure sensitive type, rewetting type, etc.SuitablyCan be used. further,In the form of adhesive, aqueous solution type, solvent type, emulsion type, solid (particularly film type), tape type, etc.SuitablyCan be used.
[0026]
  The amount of adhesive applied is the adhesive layerThickness ofIs 20 μm to 200 μm, preferably 50 μm to 150 μm. When the thickness of the adhesive layer is less than 20 μmInIt is difficult to apply the adhesive uniformly, and the unevenness of the inorganic substrateDescriptiveIn the prescribed wayMetal foilEven if it adhere | attaches, an unevenness | corrugation arises on metal foil and is unpreferable. Moreover, it exceeds 200 μmin case of,Economically unfavorable.
[0027]
  Adhesive coatingCraftFor the method, reduce the roughness curve of the surface after bonding the metal foil.YouAdhesive and method for applying the adhesive,And bonding methods are used. As the most preferable coating method, a flow coater, a knife coater, a doctor knife coater, or a die coater was used.MethodBut glueTheApply evenlyTo doCanThepreferable. Coating using a coater such as a roll coater, air spray, or airless sprayMethodThe painted surfaceTheDifficult to finish smooth, but laterDescriptiveIt can be employed by using an adhesion method.
[0028]
  The present inventionManufacturing methodThe metal foil used in is appropriately selected according to the purposeit canHowever, a hard material is preferable.IeAn aluminum foil or a stainless steel foil having a thickness of 0.05 mm to 0.5 mm, preferably 0.1 mm to 0.5 mm is preferable.Thickness isThis rangeOf aluminum foil or stainless steel foilAs a result, unevenness due to the inorganic substrate or the adhesive layer hardly remains, and good mirror surface properties can be obtained in the final product. Moreover, it is preferable also from viewpoints of economy, durability, workability, and the like. Copper foil can also be used. Further, ΔRa (2.5-0.8) of the metal foil is 0.15 μm or less, preferably 0.10 μm or less, more preferably 0.06 μm or less. The metal foil satisfying this condition is, for example, the surface finish specified in JIS G4305 “Cold Rolled Stainless Steel Sheet and Steel Strips. , # 240, # 320, # 400, BA, HL)ThanThe thing which surface-treated is mentioned. In addition, about the thing which added the matte process and uneven | corrugated pattern exceeding the said surface finish, use is not preferable. Further, in the case of a zinc-plated steel sheet in which zinc crystals are formed in the normal solidification process and have spangles, the surface shape ΔRa (2.5-0.8) is 0. Since it is about 5 μm, it is not preferable to use it.
[0029]
  next,Inorganic substrate and metal foilBy adhesiveGlue, but metal foil after gluingSurface ofΔRa (2.5-0.8) is 0.15 μm or less, preferably 0.10 μm or less, more preferably 0.06 μm or less. If it exceeds 0.15 μm, a sufficient smooth surface cannot be obtained in the surface shape of the final product.outstandingSpecularityIsDifficult to obtainNo.
[0030]
  Such bonding methods include pressure on inorganic substrates and metal foil layers.TheSurface pressureAdded asA steel belt press method or a multistage press method is used. FIG. 1 is a diagram for explaining a steel belt press method. The steel belt press machine 1 has a pair of steel belts 11 and 12 as rollers 13., 13And 14, Around 14Each windingShiIt has the structure which is the main part. The metal foil 21 wound in the form of a roll passes through guide rollers 31 and 32 and is applied to the surface thereof by a coating machine 41 such as a die coater.TheIt is coated and further fed between the steel belts 11 and 12 through the guide rollers 33, 34, 35, and 36, and at the same time, adhered to the advanced inorganic substrate 51. The adhesion between the two is the pressure roller 61.61 ...And 61 '61 '...It is carried out while being pressurized by the roller 13 and not by the rollers 13 and 14. That is, rollers 13 and 14 partsIn minutesSteel belt11 and 12The distance between the substratesWith the thickness ofMetal foilSum of thicknessNeed to be bigger. The inorganic substrate 51 and the metal foil 21 move while being pressed according to the rotation of the steel belt 11, and are cut into a desired size by the cutter 71 after the bonding is completed. Steel belt press methodInorganicsubstrateofAdjust the feed speed or adjust the length of the steel beltOrThus, the pressurization time can be adjusted, and further the hardening of the adhesive can be promoted by heating the steel belt. In order to improve the productivity by the steel belt press method, it is desirable to shorten the pressurization time.,For example, it is preferable to employ a two-component curing urethane, hot melt, or elastomer adhesive. Using hot melt adhesiveRuIn this case, the heating temperature is preferably 100 ° C. to 150 ° C., and the pressing time is preferably about 1 minute to 2 minutes.
[0031]
  FIG. 2 is a diagram for explaining the multistage pressing method. As shown in FIG. 2A, the multistage press 2 includes press dies 81 and 82 and a plurality of press intermediate plates 83. The inorganic substrate 51 and the metal foil 21 are laminated with an adhesive between the pressing dies 81, 82 and the pressing intermediate plate 83, or between the pressing intermediate plates, and then FIG. ) To apply pressure between the press dies 81 and 82 as shown in FIG.AddIs. In the case of the multi-stage press method, an adhesive similar to the steel belt press method is preferably used. The pressurization time in the multistage press method can be adjusted regardless of the size of the apparatus. However, since the multistage press method is a batch type, the production efficiency is inferior to that of the steel belt press method.
[0032]
  Adhesion pressure by steel belt press method and multi-stage press method is sufficient adhesion strength and smoothness after adhesionTheSecureYouTherefore, about 50 kPa to 1000 kPais necessary. Adhesive strength sufficient when less than 50kPaButObtainedZWhen the pressure is higher than 1000 kPa, the difference of ΔRa (2.5-0.8) on the metal foil tends to be larger than 0.15 μm.No.
[0033]
  On the other hand, the pressure is linear pressureAdded asRoll press methodAndVacuum press system that sucks and bonds the air between the inorganic substrate and the metal foilbyCaseInIn addition, irregularities due to the inorganic substrate and the adhesive layer are likely to occur on the surface of the metal foil, and as a result, ΔRa (2.5-0.8) tends to be larger than 0.15 μm.No.
[0034]
  Next, a decorative layer is formed on the metal foil. A decorative layer is a single layer of a coating layer or a printing layerOrCoating layerWhenConsisting of multiple layers of printing layers, the coating layer is used for the purpose of concealing the color of the metal foil, improving the design of the printed pattern, improving the adhesion of the printing layer, etc. Provided.
[0035]
  The surface shape of the coating layer is such that ΔRa (2.5-0.8) is 0.15 μm or less, preferably 0.10 μm or less, more preferably 0.06 μm or less. for that reasonInThe coating layer is transparentPaint orIt is preferable to form a paint to which a pigment has been added by applying it with a flow coater. When a spray coater is used, it is easy to generate a relatively large shape as typified by yuzu skin, and the specularity is lowered in the final product. In addition, when a roll coater is used, irregularities such as “roll eyes” are generated on the coating surface, which is also not preferable. In the case of using a pigment, the particle size of the coating film surface shape ΔRa (2.5-0.8) is 0.15 μm or less, preferably 0.10 μm or less, more preferably 0.06 μm or less. There is no particular limitation as long as the size satisfies the above. The resin that can be used and the curing method are not particularly limited as long as the above conditions are satisfied. Coating layerResin forIf it can satisfy the required performance,SpecialLimited toThatAbsent. Examples include polyester resin, amino resin, epoxy resin, polyurethane resin, acrylic resin, etc.To doPigments and dyes that can be colored according to the pattern of the coating layerTheWhat was added can be used conveniently. About curing methods, methods such as room temperature curing, heat curing, ultraviolet curing, electron beam curing, etc.TheI can illustrate,SpecialUV curing and electron beam curingOf the wayCaseInUnevenness occurs on the coating layer surfaceDifficultyTheSpecialIs preferred. Moreover, about the thickness of a coating-film layer, if the performance of the previous coating-film layer is satisfied, there will be no restriction | limiting at all. However, if it is substantially thinner than 10 μm, it is difficult to conceal the metal foil color, and if it is thicker than 200 μm, it is not economically preferable.
[0036]
  As a method of providing a printing layer on a metal foil or a coating film layer,printingA method is available. That is, for example,Transfer printing, gravure printing, screen printing, offset printing, and forming a decorative pattern using an inkjet printerMethodIs preferred.
[0037]
  However, the surface shape of the printed layer needs to be such that ΔRa (2.5-0.8) is 0.15 μm or less, preferably 0.10 μm or less, more preferably 0.06 μm or less. ΔRa (2.5-0.8) exceeds 0.15 μm, transparent or translucent UV curable resin layerTop coat layer consisting ofThe specularity after forming is significantly reduced. Use transfer foil.TheWhen printingInΔRa (2.5-0.8) on the surface of the ink layer of the transfer foil itself is 0.15 μm or less, preferably 0.10 μm or less, more preferably 0.06 μm or less. Transfer foil with more ΔRa (2.5-0.8)UseWhen printedInOf course, ΔRa (2.5-0.8) of the printed layerButIt becomes larger than 0.15 μm.
[0038]
  In addition, the laminated body which consists of a metal foil layer and a printing layer beforehand, or,A laminate in which a metal foil layer, a coating layer and a printing layer are sequentially laminated in advance is applied to an inorganic substrate by the steel belt press method or the multistage press method described above.Glue with a certain pressureMay be. Also in this case, the surface shape on the laminate is such that ΔRa (2.5-0.8) is 0.15 μm or less, preferably 0.10 μm or less, more preferably 0.06 μm or less.
[0039]
  The present inventionManufacturing methodsoTo form the topcoat layerTransparent or translucent resin usedpaintIs a conventionally known resinpaintAnd the curing method is alsoSpecialNot limited to. However, the solvent in the paintButLacquer types, such as nitrocellulose derivatives, vinyl chloride resins, acrylic resins, vinyl acetal resins, chlorinated rubber, etc., in which the coating film is formed by physical evaporation, all of which the volatile matter in the paint evaporates. To form a coating film, and the evaporation rate of the solvent isfastAlthough it becomes a dry paint film as soon as possible, it may cause unevenness on the paint film surface, and care must be taken in the selection and drying conditions.
[0040]
  Therefore, an ultraviolet curable resin or an electron beam curable resin which does not contain any solvent or has an extremely small content is the present invention.Adopted in the manufacturing method. Transparent or translucent resinpaintHardened by UV or electron beamRuIn some cases, the resin receives a large amount of energy when cured by condensation or addition reaction, and generally has a high crosslinking density, increased hardness, excellent cleaning resistance, and a very short curing time.InThere are advantages such as excellent productivity.
[0041]
  The present inventionManufacturing methodUV-curable coatings that can be used for coatings form transparent or translucent coatings with excellent coating propertiesbe able toPreferably a paintAvailable. The UV curable paint contains a reactive copolymer, a photopolymerizable compound and a photopolymerizable initiator as essential components, and if necessary, an additive for colorant paint is added.Thecan get. For example, the reactive copolymer mainly includes alkyd resin, polyester resin, acrylic resin, polyurethane resin, epoxy resin and the like. Examples of the photopolymerizable compound (polymerizable monomer) include unsaturated polyester and styrene. As the photopolymerizable initiator, carbonyl compounds, organic peroxides, azo compounds, halides, sulfur compounds and the like can be mainly used.
[0042]
  Transparent coating formed by electron beam curable resinAlsoThe translucent coating film is made of a resin that can be crosslinked and polymerized by electron beam irradiation. Unlike the UV curable resin, the resin cured by this method is less discolored and deteriorated by UV,ProductIt has the advantage that it can be used outdoors. The resin includes functional group-containing substrates having a saturated bond as a skeleton, such as acrylic resin, polyester resin, epoxy resin, amino resin (melamine resin, etc.), polyamide resin, and urethane resin, and groups that can be added or polymerized with these functional groups. It comprises a vinyl-based monomer having a reactive diluent or a cross-linkable oligomer, if necessary. Examples of the vinyl monomers include acrylic acid, methacrylic acid, allyl alcohol, maleic anhydride, methylolacrylamide, methacrylamide, hydroxylethyl acrylate, hydroxylethyl methacrylate, glycidyl acrylate, aminoalkyl, aminoalkyl methacrylate, etc. There is. Examples of the reactive diluent include acrylic acid esters, methacrylic acid esters, acrylonitrile, methacrylonitrile, styrene, and α-methylstyrene. Examples of the crosslinkable oligomer include compounds having 2 to 4 polymerizable vinyl groups and a molecular weight of 1000 or less, such as diallyl phthalate, ethylene glycol methacrylate, tetraethylene glycol di (meth) acrylate, and bis- (ethylene glycol). Phthalate) di (meth) acrylate, bis- (diethylene glycol phthalate) di (meth) acrylate, polyethylene glycol di (meth) acrylate, polypropylene glycol di (meth) methacrylate and the like.
[0043]
  Ra (2.5) on the surface of the transparent or translucent resin layer is 0.15 μm or less, preferably 0.10 μm or less, more preferably 0.06 μm or less. If it is larger than 0.15 μm, it may be due to a decrease in gloss, sharpness, etc.RSpecularity is inferior. As a method for forming such a surface shape, a flow coater is used. Use spray coaterDoIn this case, it is easy to generate a relatively large shape represented by yuzu skin, and the specular reflection direction of light incident on the coating film surface changes, resulting in a decrease in specularity. In addition, when a roll coater is used, irregularities such as “roll eyes” are formed on the coating surface.easy.More,In recent years, there is also a method in which a UV transparent or translucent film is bonded by a roll press and then cured by UV irradiation. This method is also uneven on the coating surface like a roll coater.ButAriseeasy.
[0044]
  Also,The coating amount isTop coat layerThe coating amount is good so that the thickness of the transparent or translucent resin layer is larger than 20 μm and not larger than 200 μm.,20 g / m²~ 250g / m²The degree is preferred. In order to obtain a smooth surface using the leveling after coating, the larger the coating amount, the better. Therefore, the coating thicknessTheIs preferably larger than 20 μmNew. However, these UV curing methods use UV light.it canCoating thicknessTheBigBecause I have toThe coating thickness is preferably 200 μm or less. In addition,The present inventionManufacturing methodThe term “transparent or translucent” means a total light transmittance of 70 to 100%.
[0045]
【Example】
  Less than,The present inventionManufacturing methodExamples and comparative examples illustrate the present invention.The method of this implementationThere are no restrictions by example. The surface roughness (Ra) of each layer was measured according to JIS B0601 appendix. In addition, about the metal foil layer, the coating-film layer, and the printing layer, it measured in the middle of preparation. Table 2 shows the measurement conditions.
[0046]
[Table 2]
  Ra Cut-off (mm) Evaluation length (mm)
  Ra (0.8) 0.8 8
  Ra (2.5) 2.5 8
[0047]
  Example 1
  First, a moisture curable urethane sealer (trade name Toa AS, manufactured by Toupe Co., Ltd.) is applied to a calcium silicate plate (trade name Celston, 6 mm thick, manufactured by Ask Co., Ltd.) that has been previously polished with a polishing paper count 120. Sealer) 100g / m²Apply and leave in the room for 24 hours, then stackTheThen, it was left to cure for 2 weeks. next,thickness100g / m of hot melt adhesive on the back of 0.1mm stainless steel foil (made by Kawasaki Steel Co., Ltd., SUS304 BA finish) using a die coater²(Manufactured by Takeda Pharmaceutical Co., Ltd.) was applied, allowed to stand for 30 seconds after application, and then adhered to the calcium silicate plate by a steel belt press method with a press pressure of 300 kPa. The substrate having this metal foil layer is placed in a dryer adjusted to 100 ° C. for 5 minutes.whileNeglectShiAfter the surface of the metal foil was brought to about 50 ° C., a paint for a coating layer (made by Nippon Paint Co., Ltd., trade name Lureel 310 / solvent urethane type) was applied with a flow coater, and the dryer was adjusted to 100 ° C. Baking was performed for 5 minutes to form a coating layer having a thickness of 30 μm. Next, the transfer foil (Dai Nippon Printing Co., Ltd. natural stone pattern) was subjected to hot roll transfer under the conditions of rubber hardness 70, roll temperature 200 ° C., feed rate 3 m / min to form a printing layer. Next, using a flow coater on the printed layer, an ultraviolet curable coating (manufactured by Nippon Paint Co., Ltd., trade name AF1 clear) 80 g / m²Was applied. After leaving still indoors for 2 minutes, it was irradiated with ultraviolet rays and cured to form a topcoat layer (transparent or translucent resin layer).
[0048]
  Example 2
  In the same manner as in Example 1, a sealer was applied to the calcium silicate plate and cured. next,thickness100g / s each of synthetic rubber adhesive (Konishi Co., Ltd., trade name Bond G series) on the back of 0.1mm stainless steel foil (Kawasaki Steel Co., Ltd., SUS304 No.4 finish) and calcium silicate plate surface m²Each was applied by air spray. Leave for 1 minute after applicationdidAfter, stainless steel foil and calcium silicate plateGlueAfter lightly pressing with a hand roll, multi-stage pressing was performed under the conditions of a press pressure of 300 kPa and a pressurization time of 60 minutes to bond the stainless steel foil and the calcium silicate plate. Then makeup layerWhenForm the topcoat layer in the same way as in Example 1.ShiIt was.
[0049]
  Example 3
  As in Example 1, a sealer was applied to a calcium silicate plate, cured, and a metal foil and a calcium silicate plate were bonded together. A coating layer was not formed. Next, the transfer foil (natural stone pattern manufactured by Toppan Printing Co., Ltd.) was subjected to hot roll transfer under the conditions of rubber hardness 70, roll temperature 200 ° C., and feed rate 3 m / min to form a printing layer. Next, a top coat layer was formed in the same manner as in Example 1.
[0050]
  Example 4
  As in Example 2, a sealer was applied to a calcium silicate plate, cured, and a metal foil and a calcium silicate plate were bonded together. The metal foil used was 0.1 mm thick aluminum foil (manufactured by Tokai Aluminum Foil Co., Ltd.). The coating layer, printing layer, and top coat layer were the same as in Example 1.
[0051]
  Comparative Example 1
  In the same manner as in Example 1, a sealer was applied to the calcium silicate plate and cured. Next, an acrylic urethane emulsion type adhesive (manufactured by Konishi Co., Ltd., trade name CVC series) 80 g / m on the same aluminum foil back surface as in Example 4.²Roll coater-Was applied. Further, the aluminum foil and the calcium silicate plate were bonded by a vacuum pressing method under the conditions of a pressing pressure of 300 kPa, a temperature of 110 ° C., and a pressing time of 3 minutes. The coating layer, printing layer, and top coat layer were the same as in Example 1.
[0052]
  Comparative Example 2
  In the same manner as in Example 1, the coating layer was formed. Next, the transfer pattern (marble pattern manufactured by Washin Chemical Industry Co., Ltd.) is printed by roll transfer under the conditions of rubber hardness 70, roll temperature 200 ° C, and material feed rate 3m / min. did. Next, the same topcoat layer as in Example 1 was formed.
[0053]
  Comparative Example 3
  The printing layer was formed in the same manner as in Example 1. Next, a UV transparent or translucent film (manufactured by Nippon Paint Co., Ltd.) is bonded with a roll press at a rubber hardness of 70, a roll temperature of 200 ° C., and a material feed rate of 3 m / min. Layers were formed.
[0054]
  Comparative Example 4
  As in Example 2, a sealer was applied to a calcium silicate plate, cured, and a metal foil and a calcium silicate plate were bonded together. In addition, a 0.1 mm thick hot-dip galvanized steel sheet (manufactured by Kawasaki Steel Corporation, Regular Spangle) was used as the metal foil. The coating layer, printing layer, and top coat layer were the same as in Example 1.
[0055]
  Comparative Example 5
  A calcium silicate plate (trade name Celston 6 mm, manufactured by Ask Co., Ltd.) previously polished with a polishing paper count 120 was used. After leaving this substrate in a 100 ° C. atmosphere for about 5 minutes, a moisture coatable urethane sealer (manufactured by Nippon Paint Co., Ltd., trade name U-60) was applied with a roll coater to 60 g / m.²Applied. Thereafter, UV curable paint (trade name Ubicoat 60 Sanding Sealer, manufactured by Nippon Paint Co., Ltd.) 60 g / m²A roll coater-And it apply | coated with the natural reverse coater, and then, it irradiated with the ultraviolet-ray and hardened. Immediately thereafter, polishing was performed with a polishing paper count 180. Next, baking type urethane paint (made by Nippon Paint Co., Ltd., trade name Leel 310) 110 g / m²Was applied by a flow coater and baked in a 100 ° C. atmosphere for 5 minutes. The processing after roll transfer was performed in the same manner as in Example 1.
[0056]
  Table 3 shows Ra (2.5), Ra (0.8), and ΔRa (2.5-0.8) of each layer of the test specimens prepared in Examples and Comparative Examples. From Table 3, as for the decorative board of an Example, (DELTA) Ra (2.5-0.8) of the surface shape under a topcoat layer is small compared with a comparative example, and Ra (2.5) on a topcoat layer is also small. As a result, it turns out that it is excellent in specularity.
[0057]
[Table 3]

[0058]
【The invention's effect】
  The present inventionManufacturing methodAccording to the present invention, it is possible to provide a decorative board that has nonflammability, heat resistance, and washing resistance, and that is further excellent in design, particularly in specularity.In particular,The manufacturing method of the present invention uses such a decorative board.While maintaining processability and work volume equivalent to conventional decorative panels,It can be provided with high productivity. Of the present inventionObtained by manufacturing methodThe decorative boardSpecialSuitable for kitchen panels placed around the kitchen gas stoveIsThe
[Brief description of the drawings]
FIG. 1 is a diagram for explaining a steel belt press method.
FIG. 2 is a diagram for explaining a multistage pressing method.
[Explanation of symbols]
1 Steel belt press machine
11,12 Steel belt
13, 14 rollers
21 Metal foil
31, 32, 33, 34, 35, 36 Guide rollers
51 Inorganic substrate
61, 61 'Pressure roller
71 cutter
81,82 Die for press
83 Press intermediate plate

Claims (3)

In a method for producing a specular decorative board , in which an adhesive layer, a metal foil layer, a coating layer or a printing layer, a decorative layer composed of a coating layer and a printing layer, and a top coat layer are laminated in this order on an inorganic substrate Then, an adhesive is applied to the surface of the inorganic substrate and / or the back surface of the metal foil, and the inorganic substrate and the metal foil are bonded to each other by applying a surface pressure of 50 kPa to 1000 kPa by a steel belt press method or a multistage press method. By forming an adhesive layer and a metal foil layer on top and providing a decorative layer on the metal foil layer, the center line average roughness and cutoff of 0.8 mm when the cut-off surface of the decorative layer is 2.5 mm the center line a step for the difference between the roughness 0.15μm below average, the transparent or translucent ultraviolet or electron beam curable resin coating material flow coater onto the surface of the decorative layer when the And cloth, by providing a transparent or translucent topcoat layer is cured by a step of the center line average roughness at a cut-off 2.5mm of the surface of the top coat layer and 0.15μm or less A method for producing a specular decorative board characterized by the above . The step of making the difference between the center line average roughness at the cut-off surface 2.5 mm and the center line average roughness at the cut-off surface 0.8 mm below 0.15 μm on the metal foil in advance A layer is provided to form a laminated body, and an adhesive is applied to the surface of the inorganic substrate and / or the back surface of the metal foil of the laminated body. 2. The method for producing a specular decorative sheet according to claim 1 , wherein adhesion is performed by applying a surface pressure, and an adhesive layer, a metal foil layer, and a decorative layer are provided on the inorganic substrate . The method for producing a specular decorative sheet according to claim 1 or 2, wherein the metal foil is an aluminum foil or a stainless steel foil .

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