JP2004269792A - Multilayer film-coated powder formulation and coloring matter using the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a multilayer film-coated powder that is capable of enhancing forgery prevention performance, genuineness determination and hilighting effect and provide a colored article using the same. <P>SOLUTION: This composition and the colored article 2 comprise a plurality of multilayer film-coated particles having different spectrophotometric properties and the colored article colored with the composition. In a preferred embodiment, the base particles comprise a mixture of optically transparent particles and opaque ones. Moreover, the opaque particle has preferably magnetic properties. <P>COPYRIGHT: (C)2004,JPO&NCIPI

Description

【００２８】
（式中、Ｒ_{ｊ＋１，ｊ}：下から第ｊ番目の層とその直上の層との間の振幅反射強度、
ｊ：１以上の整数（ｊ−１＝０は基盤を示す）、
ｉ：虚数単位、
ｒ_{ｊ＋１，ｊ}：下から第ｊ番目の層とその直上の層との間の界面のフレネル反射係数、
Ｒ_{ｊ，ｊ−１}：下から第ｊ−１番目の層とその直上の層との間の振幅反射強度、
２δ_ｊ：下から第ｊ番目の層における位相差、
λ：所望の反射光波長、
ｎ_ｊ：下から第ｊ番目の層の屈折率、
ｄ_ｊ：下から第ｊ番目の層の膜厚、
φ_ｊ：下から第ｊ番目の層への光の入射角。）
【００２９】
上記の様にして得られた多層膜反射強度Ｒ_ｆｌａｔを基体粒子の形状により補正する手法としては特に限定されないが、該Ｒ_ｆｌａｔ値をさらに下記式３
【００３０】
【数２】

【００３１】
（式中、θ：最外層への入射角を示す）
に適用させ、Ｒ（λ）値が所望の波長で最大値または最小値になるように各被覆層の膜厚を求めることにより行う手法が好ましい。
Ｒ_ｆｌａｔ値を上記式３に適用させるということは、多層膜被覆粉体への光入射角の角度分布を１個の被覆半球への光入射角度分布に近似することにより上記式２の解を補正することを意味する。
この各被覆膜の膜厚を求める場合には、コンピュータによるシミュレーションで行うことが効率的である。
【００３２】
次いで、各被覆膜を、上記のようにして求められた膜厚になるように、基体粒子上に製膜する。
但し、先にも述べたが、多層膜被覆粉体における実際の製膜作業においては、設計値通りの膜厚になるまで実膜厚を直接監視しながら行うことは不可能であり、そのため、製膜作業中の膜厚の監視は、各被覆層を被覆した被覆物体の反射強度が最大値または最小値になる波長を分光光度計にて測定し、該膜厚に相対する最大または最小反射波長値に達した時点で製膜作業を終了させることが考えられる。
しかしながら基材が粉体の場合においては、その粒子形状および粒子径に依存する各被覆層の曲率によって、最大または最小反射波長測定値と膜厚との関係に狂いが生じ、分光光度計にて測定される最大または最小反射波長が所望の値になるように製膜すると、最終的に得られる多層膜被覆粉体が、所望の波長で所望の反射強度とならないという問題が生じる。
そのため、基体粒子の形状および粒子径に依存する各被覆層の曲率による補正が必要になる。
【００３３】
この補正手法としては、特に限定されないが、選定した基体粒子上に選定した各被覆層を段階的に数種類に膜厚を変えて被覆して粒径補正用膜被覆粉体とし、該粒径補正用膜被覆粉体の各被覆層の実膜厚値（ｄ_Ｍ）を測定し、また、該膜被覆粉体のそれぞれを分光光度計にて測定し、それぞれの粒径補正用膜被覆粉体における各被覆層の光学膜厚（ｎｄ）を求め、各粒径補正用膜被覆粉体の各被覆層の実膜厚値と屈折率（ｎ）との積（ｎｄ_Ｍ）に対する各被覆層の光学膜厚（ｎｄ）の比（ｎｄ／ｎｄ_Ｍ）を求め、多層膜反射強度を求める上記漸化式２の２δ_ｊに上記比（ｎｄ／ｎｄ_Ｍ）値を乗じて各被覆層を有する粉体の分光光度特性を補正し、該補正分光光度特性になるように各被覆層を製膜することにより行うことが好ましい。
【００３４】
なお、上記粒径補正用膜被覆粉体の各被覆層の実膜厚値（ｄ_Ｍ）を測定するさいの手法としては、特に限定されないが、該粒径補正用膜被覆粉体のそれぞれを切断しその切断面から測定することにより行うことが好ましい。また、前記粒径補正用膜被覆粉体を切断する際には、集束イオンビーム（ＦＩＢ）加工により行うことが、その切断面が明瞭になり、各被覆層の実膜厚値（ｄ_Ｍ）の測定に好適である。
【００３５】
前記多層膜被覆粉体に使用される基体粉体としては、特に限定されないが、本発明においては、光透過性物質のものと光不透過性物質のものの双方に大別される。
光透過性物質としては、光を透過するものであれば特に限定されないが、 シリカ、ガラスビーズ、シラスバルーン（中空ケイ酸粒子）、微小炭素中空球（クレカスフェアー）、アエロジル、シリカ微小中空球、炭酸カルシウム微小中空球、パーライト、ベントナイト、合成雲母、白雲母など雲母類、カオリン等の無機物セルロースパウダー、酢酸セルロースパウダー、ポリアミド、エポキシ樹脂、ポリエステル、メラミン樹脂、ポリウレタン、酢酸ビニル樹脂、ケイ素樹脂、アクリル酸エステル、メタアクリル酸エステル、スチレン、エチレン、プロピレン等の有機物等が挙げられる。
【００３６】
光不透過性物質としては、光を透過しないものであれば特に限定されないが、鉄、ニッケル、クロム、チタン、アルミニウム等の金属、また、鉄、ニッケル、クロム、チタン、アルミニウム、ケイ素等の外、カルシウム、マグネシウム、バリウム等の金属の酸化物、金属窒化物、金属炭化物、金属硫化物、金属フッ化物、金属炭酸塩、金属燐酸塩等、ホワイトカーボン、炭酸カルシウム、パーライト、タルク、ベントナイト、カオリン等の非金属無機物等を用いることができる。また、光不透過性物質の基体粒子の中でも、磁性体のものを用いることにより、本発明の配合物および着色物に磁性を付与し磁性トナー、磁性インク、磁性識別可能でかつ偽造防止効果のある着色物として適用できる。
【００３７】
前記多層膜被覆粉体に使用される基体粒子の形状としては、球体、亜球状態、正多面体等の等方体、直方体、回転楕円体、菱面体、板状体、針状体（円柱、角柱）などの多面体、さらに粉砕物のような全く不定形な粉体も使用可能である。本発明の配合物および着色物において、基体粒子として板状体で、光透過性のものと光不透過性のものとを組合せて用いる際には、図２に示すように、光透過性物質を基体とする多層膜被覆粉体と光不透過性物質を基体とする多層膜被覆粉体とが接触し易くなり、それらがあたかも１つの多層膜被覆粉体であるかのように作用する。また、非接触でなくても、媒体を用いて該多層膜被覆粉体を配列させ、該多層膜被覆粉体濃度などを調整し、該粉体の積層状態、積層段数等を考慮し、所望の状態にすることができる。
【００３８】
さらに、これらの基体は、粒径については特に限定するものでないが、０．０１μｍ〜数ｍｍの範囲のものが好ましい。
また、基体粒子の比重としては、０．１〜１０．５の範囲のものが用いられるが、得られた粉体を液体等に分散させて使用する場合には、流動性、浮遊性の面から０．１〜５．５が好ましく、より好ましくは０．１〜２．８、更に、好ましくは０．５〜１．８の範囲である。得られた粉体を液体等に分散させて使用する場合、基体の比重が０．１未満では液体中の浮力が大きすぎるため、膜を多層あるいは非常に厚くする必要があり、不経済である。一方、１０．５を超えると、浮遊させるための膜が厚くなり、同様に不経済である。
【００３９】
本発明の配合物および着色物に用いられる多層膜被覆粉体においては、前記のように、上記粉体基体粒子を屈折率が互いに異なる複数の被膜層を用い、各被膜層の屈折率および層厚を適宜選択して被覆することにより、その干渉色により特定の色系に着色しかつカラーシフトを発現する粉体とすることができる。
このような多層膜を形成する方法としては、特に限定されず、国際公開ＷＯ９６／２８２９９号公報に記載された金属アルコキシドの加水分解による方法等が挙げられるが、この方法は、原材料が高く、危険物である有機性溶媒を反応溶媒として用いるため、製膜装置として防爆設備を施す必要があり、総括的に高コストとなった。このような観点から、近年は、有機溶媒を用いずに、基体粒子の表面上に金属塩の反応により金属水酸化物膜あるいは金属酸化物膜を析出させる水系製膜方法が特開平１１−１３１１１０２号等に開示されている。この水系製膜方法では、固相析出反応の溶媒として緩衡溶液を用い、ある一定のｐＨで適当な速さで固相を析出させる。
【００４０】
該製膜方法において、金属塩として使用される金属は、鉄、ニッケル、クロム、チタン、亜鉛、アルミニウム、カドミウム、ジルコニウム、ケイ素、錫、鉛、リチウム、インジウム、ネオジウム、ビスマス、セリウム、アンチモン等の他、カルシウム、マグネシウム、バリウム等が挙げられる。また、これら金属の塩としては、硫酸、硝酸、塩酸、シュウ酸、炭酸やカルボン酸の塩が挙げられる。さらにまた、前記金属のキレート錯体も含まれる。該膜被覆粉体の作成において使用される金属塩の種類は、その基体の表面に付与しようとする性質や製造に際して適用する手段に応じてそれに適するものが選択される。
【００４１】
本発明の配合物および着色物に用いられる多層膜被覆粉体は、基本的に無色透明の膜を形成し、屈折率の異なる膜を積層させて着色するため、前記のような金属とその塩が挙げられているが、干渉による着色だけでは反射及び吸収スペクトルの波形が所望の色にならない場合は、次のような金属コバルト、イットリウム、硫黄、ユーロピウム、ディスプロシウム、アンチモン、サマリウム、銅、銀、金、白金、ロジウム、イリジウム、タングステン、鉄、マンガン等の金属の硫酸、硝酸、塩酸、シュウ酸、炭酸、カルボン酸の塩等を用いることが好ましい。さらに前記金属のキレート錯体も好ましい。これらの金属の膜中の含有率は１０ｐｐｍ〜１５％、好ましくは１０ｐｐｍ〜１５％、さらに望ましくは５０ｐｐｍ〜５％である。
これらの金属の含有率が小さいときには、着色が不十分となり、多すぎると着色が強すぎて暗い色となり、明るい色の粉体が得られないという不都合が生じる。
【００４２】
これらの金属塩による金属酸化物等の膜は、複数層形成してもよく、またそれらの金属酸化物等の膜の上に、必要により金属アルコキシドの加水分解による金属酸化物等、また他の製膜方法による膜を形成することもできる。
このようにして、基体粒子の上に多層の膜を形成することができ、しかもその際、各層の厚さが所定の厚さをもつように形成条件を設定することにより、目的とする特性を得ることができる。また簡単な操作でかつ安価な原料である金属塩を用いて金属酸化物等の膜を多層に形成することができる。特に、高価な金属アルコキシドを原料とすることなく、多層膜被覆粉体とすることができる点は重要な利点である。
【００４３】
本発明の配合物および着色物に用いられる多層膜被覆粉体を製造する方法では、多層被覆膜を連続した工程として製作しても良く、また、各被覆膜を１層ずつ製作、あるいは単層製作と複層連続製作を組み合わせるなど種々の方法で製作することができる。
本発明に配合物および着色物に用いられる多層膜被覆粉体の粒径は、特に限定されず、目的に応じて適宜調整することができるが、通常は０．１μｍ〜数ｍｍが好ましく、より好ましくは０．１μｍ〜３０μｍの範囲である。
【００４４】
本発明の配合物および着色物に用いられる多層膜被覆粉体の好ましい１層の厚さ範囲は、膜物質および基体となる粒子の大きさによって異なる。膜物質が金属あるいは不透明金属酸化物、金属硫化物など吸収係数の大きい物質の場合には、基体粒子が０．１μｍ〜１μｍでは０．００００１μｍ〜０．５μｍ、基体粒子が１μｍ〜１０μｍでは０．００１μｍ〜０．７μｍ、基体粒子が１０μｍ以上では０．００１μｍ〜１．０μｍであることが好ましい。
膜物質が透明酸化物等のように吸収係数が小さい場合には、基体粒子が０．１μｍ〜１μｍでは０．０１μｍ〜１．５μｍ、基体粒子が１μｍ〜１０μｍでは０．０１μｍ〜３．０μｍ、基体粒子が１０μｍ以上では０．０１μｍ〜５．０μｍであることが好ましい。
また、上記本発明の配合物および着色物に用いられる多層膜被覆粉体の総膜厚の好ましい厚さ範囲も、基体となる粒子の大きさによって異なる。基体粒子が０．１μｍ〜１μｍでは０．１μｍ〜５μｍ、基体粒子が１μｍ〜１０μｍでは０．１μｍ〜８μｍ、基体粒子が１０μｍ以上では０．１μｍ〜２０μｍであることが好ましい。
【００４５】
本発明の配合物および着色物に用いられる多層膜被覆粉体は、上記のように、その製造方法における製膜反応の際に、特に水系溶媒中で製膜反応させる場合、製膜反応溶媒としてｐＨ一定条件の水系溶媒を用い、同時に膜被覆反応を超音波分散条件下で、基体の表面への被膜形成反応により形成される。
上記多層膜被覆粉体の作製においては、製膜反応を一定にするために、水系溶媒に緩衝剤を添加し緩衝溶液とするかあるいはあらかじめ用意された緩衝溶液が用いられる。また製膜反応の際には緩衝溶液以外の膜原料を添加し製膜する。製膜原料添加により製膜を行う際に、ｐＨが大きく変動する場合には、これを防ぐため、緩衝溶液を追加することが望ましい。
本発明で言うところのｐＨ一定とは、ｐＨが所定のｐＨの±２以内、好ましくは±１以内、より好ましくは±０．５以内を言う。
【００４６】
緩衡溶液は種々の系が用いられ、特に限定されないが、まず基体粒子が十分に分散できることが重要であり、同時に基体の表面に析出した金属水酸化物あるいは金属酸化物の膜被覆粉体も電気２重層の働きで分散でき、かつ上記の緩やかな滴下反応により緻密な被膜が製膜できる条件を満足するように選択する。
製膜反応に使用される緩衡溶液としては、析出させる固相成分に依存し、特に限定されないが、Ｔｒｉｓ系、ホウ酸系、グリシン系、コハク酸系、乳酸系、酢酸系、酒石酸系、塩酸系等が挙げられる。
【００４７】
次に一例として、特に水系溶媒中で製膜反応させる場合、高屈折率の金属酸化物と低屈折率の金属酸化物の交互多層膜を形成する方法について具体的に説明する。まず、酸化チタンあるいは酸化ジルコニウムなどの被膜を形成する場合、酢酸／酢酸ナトリウム系等の緩衡溶液中に基体粒子を浸漬し超音波発振により分散し、チタンあるいはジルコニウムなどの金属塩である硫酸チタン、硫酸ジルコニウム等を原料とし、これら金属塩の水溶液を反応系に緩やかに滴下し、生成する金属水酸化物あるいは金属酸化物を基体粒子のまわりに析出させることにより行うことができる。この滴下反応の間、ｐＨは上記緩衡溶液のｐＨ（５．４）に保持される。
反応終了後、この粉体を固液分離し、洗浄・乾燥後、熱処理を施す。乾燥手段としては真空乾燥、自然乾燥のいずれでもよい。また、不活性雰囲気中で噴霧乾燥機などの装置を用いることも可能である。
なお、この被覆される膜が酸化チタンである場合には、酸化チタンの形成は下記の反応式で示される。
【００４８】
Ｔｉ（ＳＯ_４）_２＋２Ｈ_２Ｏ→ＴｉＯ_２＋２Ｈ_２（ＳＯ_４ ）
【００４９】
硫酸チタニルのＴｉＯ_２含有量は５ｇ／リットル〜１８０ｇ／リットルが好ましく、より好ましくは１０ｇ／リットル〜１６０ｇ／リットルである。５ｇ／リットル未満では製膜に時間がかかりすぎ、また粉体処理量が減り、不経済であり、１８０ｇ／リットルを超えて高くなると希釈液が添加中に加水分解を起こし製膜成分にならず、共に不適である。
【００５０】
続いて、二酸化ケイ素あるいは酸化アルミニウムなどの被膜を形成する場合、ＫＣｌ／Ｈ_３ＢＯ_３系等にＮａＯＨを加えた緩衡溶液中に上記のチタニアコート粒子を浸漬し分散し、ケイ素あるいはアルミニウムなどの金属塩であるケイ酸ナトリウム、塩化アルミニウム等を原料とし、これら金属塩の水溶液を反応系に緩やかに滴下し、生成する金属水酸化物あるいは金属酸化物を基体粒子の周りに析出させることにより行うことができる。この滴下反応の間、ｐＨは上記緩衡溶液のｐＨ（９．０）に保持される。
反応終了後、この粉体を固液分離し、洗浄・乾燥後、熱処理を施す。この操作により、基体粒子の表面に屈折率の異なる２層の、金属酸化物膜を形成する操作を繰り返すことにより、多層の金属酸化物膜をその表面上に有する粉体が得られる。
なお、この被覆される膜が二酸化ケイ素である場合には、二酸化ケイ素の形成は下記の反応式で示される。
【００５１】
Ｎａ_２Ｓｉ_ＸＯ_２Ｘ＋１＋Ｈ_２Ｏ → ＸＳｉＯ_２＋２Ｎａ^＋＋２ＯＨ⁻
【００５２】
本発明の多層膜被覆粉体配合物は、分光光度特性の異なる複数種の多層膜被覆粉体のみを含有するものであってもよいが、着色物に適用するための利点から、各種色材組成物の形態であることが好ましい。
色材組成物の代表例としては、（１）各特定色系インキあるいは塗料様組成物（流体）および（２）各特定色系トナー、各特定色系乾式インキ様組成物（粉体）等がある。以下にこれらについて説明する。
【００５３】
（１）特定色系インキあるいは塗料様組成物（流体）の媒質（ビヒクル）としては、カラー印刷用、カラー磁気印刷用、カラー磁気塗料用に用いられる、従来公知のワニスを用いることができ、例えば液状ポリマー、有機溶媒に溶解したポリマーやモノマーなどを粉体の種類やインキの適用方法、用途に応じて適宜に選択して使用することができる。
【００５４】
上記液状ポリマーとしては、ポリペンタジエン、ポリブタジエン等のジエン類、ポリエチレングリコール類、ポリアミド類、ポリプロピレン類、ワックス類あるいはこれらの共重合体変成体等を挙げることができる。
有機溶媒に溶解するポリマーとしては、オレフィン系ポリマー類、オリゴエステルアクリレート等のアクリル系樹脂類、ポリエステル類、ポリアミド類、ポリイソシアネート類、アミノ樹脂類、キシレン樹脂類、ケトン樹脂類、ジエン系樹脂類、ロジン変性フェノール樹脂、ジエン系ゴム類、クロロプレン樹脂類、ワックス類あるいはこれらの変性体や共重合体などを挙げることができる。
有機溶媒に溶解するモノマーとしては、スチレン、エチレン、ブタジエン、プロピレンなどを挙げることができる。
有機溶媒としては、エタノール、イソプロパノール、ノルマルプロパノール等のアルコール類、アセトン等のケトン類、ベンゼン、トルエン、キシレン、ケロシン、ベンジン炭化水素類、エステル類、エーテル類あるいはこれらの変性体や共重合体などを挙げることができる。
【００５５】
（２）特定色系トナー、特定色系乾式インキ、特定色系乾式塗料様組成物（粉体）は、上記分光光度特性の異なる複数種の多層膜被覆粉体を、樹脂とあるいは必要に応じて調色材とを、スクリュー型押出機、ロールミル、ニーダなどで直接混練し、ハンマミル、カッターミルで粗粉砕したあと、ジェットミルなどで微粉砕し、エルボージェットなどで必要な粒度に分級することにより粉体状シアン色色材組成物を得ることができる。また、乳化重合法や懸濁重合法などの重合法を用いて、粉体状特定色系塗料組成物とすることもできる。
さらに、多層膜被覆粉体と樹脂、調色剤などの添加剤および溶剤をコロイドミルや３本ロールで液状化し、インキ塗料などの液状特定色系塗料組成物とすることもできる。
【００５６】
明度を上げるための調色材としては、白色顔料（展色材）である、例えば、酸化チタン、酸化亜鉛、酸化錫、酸化珪素、酸化アンチモン、酸化鉛等あるいはこれらの複合酸化物類、また炭酸カルシウム、炭酸マグネシウム、炭酸バリウム等の炭酸塩、あるいは硫酸バリウム、硫酸カルシウムのような硫酸塩類、硫酸亜鉛のような硫化物あるいは前記酸化物や炭酸塩および硫酸塩を焼結した複合酸化物、複合含水酸化物類が挙げられる。
【００５７】
彩度、色相を調整するため、特にフルカラー用混色で色再現用に使用する場合の調色材としては、青色顔料である（有機染料・顔料）アルカリブルーレーキ、ピーコックレーキ、ピーコックレーキブルー等のレーキ染料およびレーキ顔料、オイルブルー等、オイル染料顔料、アルコールブルー等のアルコール染料、フタロシアニン、銅フタロシアニン等のフタロシアニン系顔料等、（無機顔料）ウルトラマリン等の酸化物硫化物複合顔料、鉄青、ミロリーブルー等の銅系群青紺青顔料類、コバルトブルー、セルリアンブルー等の酸化コバルト系複合酸化物類青色顔料、青色系有機染料および顔料および青色無機顔料アルカリブルーレーキ、ピーコックブルーレーキ等のレーキ染料、レーキ系顔料無金属フタロシアニン、銅フタロシアニン等のフタロシアニン系染顔料および緑色顔料であるクロームグリーン、ジンクグリーン、酸化クロム、含水クロム（ビリジアン）等のクロム系酸化物および含水酸化物、エメラルドグリーン等の銅系酸化物、コバルトグリーン等のコバルト系酸化物等の無機顔料あるいは、ピグメントグリーン、ナフトールグリーンなどのニトロソ顔料、グリーンゴールド等のアゾ系顔料、フタロシアニングリーン、ポリクロム銅フタロシアニン等のフタロシアニン系顔料、マラカイトグリーンレーキ、アシッドグリーンレーキなどのレーキ系、オイルグリーン等、オイル染料顔料、アルコールブルー等のアルコール染料顔料等有機染顔料が挙げられる。しかし本発明はこれらのみに限定されるものではない。
【００５８】
さらに、微妙な色調制御において、青色、黄色、赤紫色などの顔料や染料を用いて調色することが必要な場合は、これらの顔料を添加することにより最適の特定色とすることが好ましい。
この特定色系塗料組成物の場合、（ａ）上記粉砕法で製造する場合の樹脂としては、特に限定されるものではないが、ポリアミド、エポキシ樹脂、ポリエステル、メラミン樹脂、ポリウレタン、酢酸ビニル樹脂、ケイ素樹脂、アクリル酸エステル、メタアクリル酸エステル、スチレン、エチレン、ブタジエン、プロピレン及びこれらの誘導体の重合体または共重合体などが挙げられる。
（ｂ）重合法の場合、エステル、ウレタン、酢酸ビニル、有機ケイ素、アクリル酸、メタアクリル酸、スチレン、エチレン、ブタジエン、プロピレン等のうち１種あるいは複数の混合物から重合を開始させ、重合体あるいはこれらの共重合体などが形成される。
【００５９】
本発明の多層膜被覆粉体配合物からなる色材組成物の代表例としては、上記のように、（１）各特定色系インキあるいは塗料様組成物（流体）および（２）各特定色系トナー、各特定色系乾式インキ様組成物（粉体）の形をとる。
また、流体状の場合には、特定色系インキ、塗料等であり、前記調色材、乾燥の遅い樹脂には固化促進剤、粘度を上げるために増粘剤、粘性を下げるための流動化剤、粒子同志の分散のために分散剤などの成分を含ませることができる。
一方、粉体の場合には、（ａ）粉砕法で粉体を製造する場合には、前記調色材、乾燥の遅い樹脂には固化促進剤、混練の際の粘性を下げるためには流動化剤、粒子同志の分散のためには分散剤、紙等への定着のための電荷調整剤、ワックスなどの成分を含ませることができる。
（ｂ）重合法を用いる場合には、前記調色材、重合開始剤、重合促進剤、粘度を上げるためには増粘剤、粒子同志の分散のためには分散剤、紙等への定着のための電荷調整剤、ワックスなどの成分を含ませることができる。
上記多層膜被覆粉体配合物は、湿式および乾式カラー印刷や湿式および乾式カラー磁気印刷に適用できるほか、可視光、非可視光（紫外域および赤外域）、蛍光発色および磁気、さらに電気（電場の変化）の種の組合せの識別機能を付与し、印刷物の偽造防止用カラー磁性インキなどセキュリティ機能を必要とする他の用途に適用することができる。
【００６０】
前記各特定色系インキあるいは塗料様組成物または各特定色系トナー、各特定色系乾式インキ様組成物、各特定色系乾式塗料組成物を、基材に印刷、溶融転写または被塗装体に塗布する場合、塗料組成物中の多層膜被覆粉体と樹脂の含有量の関係は、体積比で１：０．５〜１：１５である。媒質の含有量が少な過ぎると塗布した膜が被塗装体に固着しない。また、多過ぎると顔料の色が薄くなりすぎ良いインキまたは塗料といえない。
また、各色系インキあるいは塗料組成物中の各色系色材および樹脂を合わせた量と溶剤の量との関係は、体積比で１：０．５〜１：１０であり、溶剤の量が少な過ぎると塗料の粘度が高く、均一に塗布できない。また、溶剤の量が多過ぎると塗膜の乾燥に時間を要し塗布作業の能率が極端に低下する。
【００６１】
また、基材に印刷、溶融転写または被塗装体に塗料を塗布した際の塗膜の色の濃度は、被塗装体の単位面積当たりに載った顔料の量によって決まる。塗料が乾燥した後の被塗装体上の多層膜被覆粉体の量は、均一に塗布した場合の面積密度で、１平方メートルあたり０．１〜３００ｇであり、好ましくは０．１〜１００ｇであれば良好な塗装色が得られる。面積密度が前記の値より小さければ被塗装体の地の色が現れ、前記の値より大きくても塗装色の色濃度は変わらないので不経済である。すなわち、ある厚さ以上に顔料を被塗装体上に載せても、塗膜の下側の顔料にまでは光りが届かない。かかる厚さ以上に塗膜を厚くすることは、塗料の隠蔽力を越えた厚さであるので塗装の効果がなく不経済である。ただし、塗膜の磨耗を考慮し、塗膜の厚さが摩り減るため厚塗りする場合はこの限りではない。また特定の意匠等を部分的に形成する場合にもこの限りではない。
【００６２】
なお、本発明の多層膜被覆粉体配合物およびそれを用いた着色物に蛍光発色性を付与することもできる。
その付与方法としては、特に限定されないが、多層膜被覆粉体に、特開２０００−８７１０３号公報に示すような蛍光物質を含有する被覆層を更に設ける方法や、カラーシフトする粉体と蛍光物質を配合して色材組成物とする方法がある。
【００６３】
【実施例】
以下に本発明を実施例によって更に具体的に説明するが、勿論本発明の範囲は、これらによって限定されるものではない。
〔実施例１〕
１．原料溶液の調整
（緩衡液Ａの調整）
緩衡溶液Ａは次の溶液濃度で調整した。
０．４モルの塩化カリウムと０．４モルのホウ酸を１リットルの脱イオン水に溶解し、溶液Ｃとした。
０．４モルの水酸化ナトリウムを１リットルの脱イオン水に溶解し溶液Ｂとした。
溶液Ｂ２５０ｇに対し溶液Ｃ１１５ｇを混合均一化し、緩衡液Ａとした。
【００６４】
（緩衡液Ｂの調整）
緩衡溶液Ｂは次の溶液濃度で調整した。
塩化カリウム２９．８ｇ、ホウ酸２４．７ｇを脱イオン水１リットルに溶解して、溶液Ｄを得た。
次に、水酸化ナトリウム１６．０ｇを、脱イオン水１６ｇと脱イオン水１リットルに溶解して、溶液Ｅを得た。
溶液Ｄ２００ｇと溶液Ｅ８０ｇを混合し、緩衡液Ｂとした。
【００６５】
（ケイ酸ナトリウム水溶液の調整）
ケイ酸ナトリウム水溶液は次の組成で調整した。
ケイ酸ナトリウムを脱イオン水に徐々に加え、均一化しＳｉＯ_２含有量が１０％の溶液とした（以下「ケイ酸溶液」と呼ぶ）。
（チタニア滴下液の調整）
チタニア滴下液は次の組成で調整した。
２０％塩化チタン〔ＩＩＩ〕水溶液１３３ｇに、２８％アンモニア水２７３ｇ、さらに過酸化水素水１３３ｇを混合し、ペルオキソチタン酸溶液（以下「チタン溶液」と呼ぶ）を得た。
【００６６】
２．不透明多色性磁性粉の作製（赤紫色から緑色に変化する粉体）
（第１層シリカ膜の形成）
あらかじめ用意した緩衡液Ａ、２８００ｇに、板状パーマロイ粉（平均粒径２１μｍ）（福田箔粉工業製）を１００ｇ加え、十分撹拌して懸濁させた。
前記粉体懸濁溶液をウォーターバスに入れ３０℃で保持しつつ、撹拌機により１０００ｒｐｍで撹拌しながら、１４００ｇのケイ酸ナトリウム水溶液を２６．７ｍｌ／ｍｉｎで滴下し、滴下後２時間保持し、徐々に粉体表面にシリカ膜を形成した。
反応終了後、シリカ製膜粉を含むスラリーを十分な水でデカンテーションを繰り返し、洗浄した。
洗浄後、２度目として、あらかじめ用意した緩衡液Ａ、２８００ｇに該シリカ製膜粉を加え、十分撹拌して懸濁させた。前記粉体懸濁溶液をウォーターバスに入れ３０℃で保持しつつ、撹拌機により１０００ｒｐｍで撹拌しながら、１４００ｇのケイ酸ナトリウム水溶液を２６．７ｍｌ／ｍｉｎで滴下し、滴下後２時間保持し、徐々に粉体表面にシリカ膜を形成した。
洗浄後、沈降分離により固液分離し、固形分をバットに広げ、乾燥機で１２０℃で、８時間乾燥した。
得られた乾燥粉を回転式チューブ炉で、窒素雰囲気６５０℃で３０分間熱処理を行い、酸化ケイ素被覆粉体Ａ１を得た。
【００６７】
（第２層酸化チタン膜の形成）
緩衡液Ｂ、４２００ｍｌの中に、酸化ケイ素被覆粉体Ａ１、１００ｇを十分に懸濁させ、温度調整機つき、２８ｋＨｚ、６００Ｗの超音波槽で、温度３０℃に保持し、超音波をかけ、撹拌機で撹拌しながら、チタニア滴下液１３５２ｇを１５ｍｌ／ｍｉｎで滴下し、滴下後２時間保持し、徐々に粉体表面に酸化チタン膜を形成した。
反応終了後、シリカ製膜粉を含むスラリーを十分な水でデカンテーションを繰り返し、洗浄した。
洗浄後、沈降分離により固液分離し、固形分をバットに広げ、乾燥機で１２０℃で、８時間乾燥した。
得られた乾燥粉を回転式チューブ炉で、窒素雰囲気６５０℃で３０分熱処理を行い、酸化ケイ素−酸化チタン被覆粉体Ａ２を得た。
【００６８】
（第３層シリカ膜の形成）
あらかじめ用意した緩衡液Ａ、２８００ｇに、酸化ケイ素−酸化チタン被覆粉体Ａ２、１００ｇを加え、十分撹拌して懸濁させた。
前記粉体懸濁溶液をウォーターバスに入れ３０℃で保持しつつ、撹拌機により１０００ｒｐｍで撹拌しながら、１４００ｇのケイ酸ナトリウム水溶液を２６．７ｍｌ／ｍｉｎで滴下し、滴下後２時間保持し、徐々に粉体表面にシリカ膜を形成した。
反応終了後、シリカ製膜粉を含むスラリーを十分な水でデカンテーションを繰り返し、洗浄した。
洗浄後、２度目として、あらかじめ用意した緩衡液Ａ、２８００ｇを加え、十分撹拌して懸濁させた。前記粉体懸濁溶液をウォーターバスに入れ３０℃で保持しつつ、撹拌機により１０００ｒｐｍで撹拌しながら、１３２０ｇのケイ酸ナトリウム水溶液を２６．７ｍｌ／ｍｉｎで滴下し、滴下後２時間保持し、徐々に粉体表面にシリカ膜を形成した。
洗浄後、沈降分離により固液分離し、固形分をバットに広げ、乾燥機で１２０℃で、８時間乾燥した。
得られた乾燥粉を回転式チューブ炉で、窒素雰囲気６５０℃で３０分熱処理を行い、酸化ケイ素−酸化チタン−酸化ケイ素被覆粉体Ａ３を得た。
【００６９】
３．塗布紙の作製
得られた酸化ケイ素−酸化チタン−酸化ケイ素被覆粉体Ａ３、１６ｇを１０％ポリメタアクリルアミン水溶液、１０ｍｌに練りこみ、インキ様組成物ＬＡとした。
インキ様組成物をコート紙にバーコーターで塗布し、乾燥後塗布紙ＣＰ１を得た。その色を見ると正面からの色は青であり、４５度傾けると赤紫色となり、さらに傾けて見た色は暗い茶色であった。
【００７０】
４．透明干渉粉体の作製
（酸化チタン膜の製膜）
緩衡液Ｂ、４２００ｍｌの中に白雲母（平均粒径２１μｍ）（レプコ製）を２２０ｇ加え、温度調整機につき、２８ｋＨｚ、６００Ｗの超音波槽で温度３０℃に保持し、超音波をかけ、撹拌機で撹拌しながら、チタニア滴下液１３５２ｇを１５ｍｌ／ｍｉｎで滴下し、滴下後２時間保持し、徐々に粉体表面にシリカ膜を形成した。
反応終了後、シリカ製膜粉を含むスラリーを十分な水でデカンテーションを繰り返し、洗浄した。
洗浄後、沈降分離により固液分離し、固形分をバットに広げ、乾燥機で１２０℃で、８時間乾燥した。
得られた乾燥粉を回転式チューブ炉で、窒素雰囲気５００℃で３０分間熱処理を行い、酸化チタン被覆粉体Ｂを得た。
【００７１】
５．塗布紙の作製
得られた酸化ケイ素−酸化チタン被覆粉体Ａ３、１６ｇをポリメタアクリルアミン水溶液、１０ｍｌに練りこみ、インキ様組成物ＬＢ１とした。
インキ様組成物ＬＢ１をコート紙にバーコーターで塗布し、乾燥後塗布紙ＣＰ２を得た。
チタン被覆粉体Ｂ、１２ｇを１０％ポリメタアクリルアミン水溶液、１０ｍｌに練りこみ、インキ様組成物ＬＢ２とした。インキ様組成物ＬＢ２を乾燥後塗布紙ＣＰ２にさらにバーコーターで塗布し、乾燥後塗布紙ＣＰ３を得た。
ＣＰ３の色を見ると正面からの色は黄緑であり、４５度傾けると青色となり、さらに傾けて見た色は赤紫色であった。上記３．で作製した塗布紙ＣＰ１に比べ、ＣＰ３の方が鮮やかに色変化した。
【００７２】
６．薄膜状物質１の形成
基体が光不透過性物性である膜被覆粉体Ａ３、１０ｇを、アクリル樹脂０．５ｇを溶解したアルコール溶液５００ｍｌに十分分散し、広さ２００平方センチメートル、深さ５ｃｍの底面が四角形のプラスチック容器に均一に入れ沈降させた。粉体が全て沈降した後、液分を吸引機で吸出し、６０℃で１２時間乾燥した。乾燥物は薄膜Ａ１となった。
乾燥後、この薄膜が形成された容器に、基体が光透過性物質である膜被覆粉体Ｂ、１０ｇを、アクリル樹脂０．５ｇを溶解したアルコール溶液５００ｍｌに十分分散し流し込み、粉体が全て沈澱した後６０℃で１２時間乾燥した。乾燥物は薄膜１Ｂとなった。
結果、この薄膜状物質は、顕著な多色性を有し、さらにこの薄膜１Ｂのその色を見ると正面からの色は黄緑であり、４５度傾けると青色となり、さらに傾けて見た色は赤紫色であった。また薄膜の磁性は３１Ａ・ｍ^２／ｋｇ（磁場７９０ｋＡ／ｍ）であった。
【００７３】
７．薄膜状物質２の形成
基体が光不透過性物性である膜被覆粉体Ａ３、１０ｇと基体が光透過性物質である膜被覆粉体Ｂ、１０ｇを、アクリル樹脂０．５ｇを溶解したアルコール溶液５００ｍｌに十分分散し、広さ２００平方センチメートル、深さ５ｃｍの底面が四角形のプラスチック容器に均一に入れ沈降させた。粉体が全て沈降した後、液分を吸引機で吸出し、６０℃で１２時間乾燥した。
この薄膜を顕微鏡で観察すると、比重の重い基体が光不透過性物質である膜被覆粉体Ａ３が先に沈降し層を形成し、後に比重の小さい基体が光透過性物質である膜被覆粉体Ｂが沈降した２重構造となっていた。
この薄膜状物質２は、顕著な多色性を有し、さらにこの薄膜状物質２の正面からの色は黄緑であり、４５度傾けると青色となり、さらに傾けて見た色は赤紫色であった。また薄膜の磁性は３３Ａ・ｍ^２／ｋｇ（磁場７９０ｋＡ／ｍ）であった。
これらのような干渉色は単一種類の干渉粒子だけで出すことが難しく、複数の粒子の多重干渉を応用することにより、より複雑な偽造防止効果が得られると考えられる。
なおこの際、磁性体を含む不透明な干渉粉を下層に配置することにより、磁性粉体の吸収により反射色をより鮮明にできるという効果も認められた。
【００７４】
実施例２（球状粉配向による多色性）
球状粉体を透過性粒子として使用するため、製膜を行なった。使用した緩衡溶液および製膜原料は実施例１と同様のものである。
（第１層シリカ膜の形成）
あらかじめ用意した緩衡液Ａ、２８００ｇにガラスビーズ（ユニオン社製ＵＢ１３）５００ｇ加え、十分撹拌して懸濁させた。
前記粉体懸濁液をウォーターバスに入れ３０℃で保持しつつ、撹拌機により１０００ｒｐｍで撹拌しながら、１４００ｇのケイ酸ナトリウム水溶液を２６．７ｍｌ／ｍｉｎで滴下し、滴下後２時間保持し、徐々に粉体表面にシリカ膜を形成した。
反応終了後、シリカ製膜粉を含むスラリーを十分な水でデカンテーションを繰り返し、洗浄した。
洗浄後２度目として、あらかじめ用意した緩衡液Ａ、２８００ｇを加え、十分撹拌して懸濁させた。前記粉体懸濁液をウォーターバスに入れ３０℃で保持しつつ、撹拌機により１０００ｒｐｍで撹拌しながら、１４００ｇのケイ酸ナトリウム水溶液を２６．７ｍｌ／ｍｉｎで滴下し、滴下後２時間保持し、徐々に粉体表面にシリカ膜を形成した。
洗浄後３度目として、あらかじめ用意した緩衡液Ａ、２８００ｇを加え、十分撹拌して懸濁させた。前記粉体懸濁溶液をウォーターバスに入れ３０℃で保持しつつ、撹拌機により１０００ｒｐｍで撹拌しながら、１４００ｇのケイ酸ナトリウム水溶液を２６．７ｍｌ／ｍｉｎで滴下し、滴下後２時間保持し、徐々に粉体表面にシリカ膜を形成した。
洗浄後、沈降分離により固液分離し、固形分をバットに広げ、乾燥機で１２０℃で、８時間乾燥した。
得られた乾燥粉を回転式チューブ炉で、窒素雰囲気６５０℃で３０分間熱処理を行い、酸化ケイ素被覆粉体Ｃ１を得た。
【００７５】
（第２層目酸化チタン膜の形成）
緩衡液Ｂ、４２００ｍｌの中に酸化ケイ素被覆粉体Ｃ１、３００ｇを十分に懸濁させ、温度調整機つき、２８ｋＨｚ、６００Ｗの超音波槽で温度３０℃に保持し、超音波をかけ、撹拌機で撹拌しながら、チタニア滴下液１３５２ｇを１５ｍｌ／ｍｉｎで滴下し、滴下後２時間保持し、徐々に粉体表面に酸化チタン膜を形成した。
反応終了後、酸化チタン製膜粉を含むスラリーを十分な水でデカンテーションを繰り返し、洗浄した。
洗浄後、沈降分離により固液分離し、固形分をバットに広げ、乾燥機により１２０℃で、８時間乾燥した。
得られた乾燥粉を回転式チューブ炉で、窒素雰囲気６５０℃で３０分間熱処理を行い、酸化ケイ素−酸化チタン被覆粉体Ｃ２を得た。
この粉体は４３５ｎｍ、５５３ｎｍ、６８７ｎｍにピークを有し、表面色が淡いピンク色の粉体であった。
【００７６】
（塗布紙の作製）
実施例１で得られた磁性粉Ａ３粉１６ｇを１０％ポリメタアクリルアミン水溶液、１５ｍｌに練りこみ、インキ様組成物ＬＤ１とした。
インキ様組成物ＬＤ１をコート紙にバーコーターで塗布し、乾燥後塗布紙ＣＰ４を得た。
塗布物ＣＰ４の上にさらに、実施例２の粉体Ｃ２、９ｇに対し１０％ポリメタアクリルアミン水溶液、１５ｍｌに練りこみ、インキ様組成物ＬＥとした。
インキ様組成物ＬＥを塗布紙ＣＰ４にバーコーターで塗布し、乾燥後、その塗布紙ＣＰ５の色を正面からみると赤紫色であり、傾けるにつれ、黄色、緑色と変化した。
この色変化は、球状被覆粉体と板状粉体の多重干渉によるものと考えられる。
【図面の簡単な説明】
【図１】本発明の多層膜被覆粉体配合物に含まれる粉体が有する分光光度スペクトルが多重干渉を起こす推定機構の１例を示す概念図。
【図２】本発明の多層膜被覆粉体配合物に含まれる粉体が有する分光光度スペクトルが多重干渉を起こす推定機構の他の１例を示す概念図。
【図３】本発明の多層膜被覆粉体配合物に含まれる粉体が有する分光光度スペクトルが多重干渉を起こす推定機構の別の他の１例を示す概念図。
【符号の説明】
１ 光透過性物質
２ 光不透過性物質[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a multilayer film-coated powder composition and a colored material using the same, and in particular, it is possible to enhance the effect of preventing counterfeiting of banknotes, securities, etc., and the effect of showing the color more vividly from the surroundings. The present invention relates to a multilayer coating powder formulation and a colored product using the same.
[0002]
[Prior art]
Conventionally, currency, currency, other gift certificates, gift certificates, event tickets, securities, etc. have been used in the form of printed materials, coated materials, etc. I have. These printed materials, coated materials, etc. are usually made by writing, printing, coating, etc., on paper pieces, etc., indicating their characteristics, and are lightweight and compact, convenient to carry, store and use. It is. However, using materials that are familiar to ordinary people, such as paper pieces, were sometimes illegally copied and forged.
[0003]
For the purpose of preventing such forgery, conventionally, the identification means has been used using an imprint of a mark possessed by an issuer, a handwriting by a signature, a watermark picture, or the like. However, these identification means are easily imitated by a person having a special skill or a copying / printing technique developed in recent years. It is still in use, but its credibility is getting lower. In recent years, bar code signs and the like have been used. However, since this barcode mark is an inorganic pattern consisting of image lines, it degrades the elegant image of its securities and is easily copied by advanced image analysis and duplication techniques. There is also.
[0004]
In addition, a method is adopted in which the securities are printed using a magnetic card or magnetic ink and the magnetism is identified. However, printed materials using these magnetic cards and magnetic inks are easily counterfeited due to the black or black-brown color tone that magnetic powders generally have, which impairs aesthetics and makes it easy to understand the use of the magnetic identification function. There was also a problem that. Further, a method has been adopted in which a fluorescent substance is included in the printing ink to identify the visible fluorescent color of the printed matter. However, this method of identifying a visible fluorescent color is usually a method of irradiating with a fluorescent coloring lamp and visually discriminating the color development, and is not suitable for strict discrimination of authenticity and forgery prevention.
[0005]
Also, in recent years, it is sometimes desired to make a certain object more conspicuous than surrounding objects. For example, many people prefer to express their presence, identity, personality, sensitivity, and the like. For that purpose, clothing and other belongings, carryables, and signs are given a design property or the like to make them stand out from the surroundings.
However, since various personalities are innumerable, it is no longer possible to obtain a sufficient conspicuous effect by giving a design property as in the past.
[0006]
On the other hand, the present inventors have provided a plurality of metal oxide films each having a metal different from the metal constituting the powder on the surface of the powder, in addition to the properties provided only by the original powder. We have invented a powder having another property and having a composite function (for example, see Patent Document 1).
In this powder, when the metal oxide film is provided in a plurality of layers, a special function can be given by adjusting the thickness of each layer of the film. If a coating film having a different refractive index is provided at a thickness corresponding to a quarter wavelength of light, all light is reflected. When this means is applied to a magnetic powder such as iron, cobalt, nickel or other metal powder or metal alloy powder or iron nitride powder as a core particle, a magnetic color material that shines white by totally reflecting light Magnetic powder can be manufactured.
[0007]
Further, if a colored layer is provided on the powder and a resin layer is provided thereon, a color magnetic toner can be manufactured.
In addition, the present inventors have further improved the above-mentioned powder, and have invented not only a metal oxide film alone but also a powder having a plurality of metal oxide films and a plurality of metal films alternately ( For example, see Patent Document 2), which has excellent properties as a color magnetic toner and the like.
In order to produce these powders, it is necessary to provide a plurality of metal oxide films having a uniform thickness on the powder particles. Since it is difficult to precipitate a metal compound, the present inventors disperse the powder in a metal alkoxide solution and hydrolyze the metal alkoxide to form a metal oxide film on the powder. Has been developed, and by this method, a metal oxide film having a small thickness and a uniform thickness can be formed, and in particular, a multilayer metal oxide film can be formed.
[0008]
Specifically, this method comprises dispersing a powder, particularly a metal or metal compound powder, in a metal alkoxide solution and hydrolyzing the metal alkoxide to form a metal oxide on the surface of the powder. The metal oxide film is formed on the surface, and the process is repeated to obtain a multilayer metal oxide film. By changing the type of the multilayer metal oxide film, the reflectance of the powder can be changed. It has been found that a powder having high whiteness can be obtained by selecting a combination of the upper and lower metal oxide films so as to maximize the reflectance.
Furthermore, the present inventors have disclosed a technique in which a multilayer coating film made of a transparent film capable of transmitting light is provided on the surface of the base particles, and the powder is colored by the light interference action of the multilayer coating film (for example, See Patent Document 3.).
[0009]
[Patent Document 1]
JP-A-6-228604
[Patent Document 2]
JP-A-7-90310
[Patent Document 3]
WO 96/28269 pamphlet
[0010]
[Problems to be solved by the invention]
An object of the present invention is to further improve the above-described conventional technology, and to provide a multilayer film-coated powder composition capable of improving forgery prevention, authenticity discrimination, and conspicuous effects, and a colored material using the same. .
[0011]
[Means for Solving the Problems]
As a result of intensive studies, the present inventors have been able to solve the above problem by adopting the following configuration.
That is, the present invention is as follows.
(1) A composition containing a plurality of types of multilayer-coated powders having different spectrophotometric characteristics.
(2) The composition according to the above (1), wherein the multi-layer film-coated powder contains at least both a substance whose base particles are a light-transmitting substance and a substance that is a light-impermeable substance. object.
(3) The compound according to the above (2), wherein the light-impermeable material is a magnetic material as the multilayer film-coated powder.
[0012]
(4) A colored material colored with a compound containing a plurality of types of powder coated with a multilayer film having different spectrophotometric characteristics.
(5) The coloring according to the above (4), wherein at least both the base particle of which is a light-transmitting substance and the base particle of which is a light-impermeable substance are used as the multi-layer coating powder. object.
(6) The colored article according to (5), wherein the light-opaque substance is a magnetic substance as the multilayer-coated powder.
[0013]
By blending multiple types of multi-layer coated powders with different spectrophotometric characteristics, it is now possible to express unique spectrophotometric characteristics different from the case of using a single multi-layer coated powder .
This is because a single multilayer-coated powder has individual spectrophotometric characteristics, but by mixing a plurality of types of multilayer-coated powders having different spectrophotometric characteristics, the spectral It is presumed that the light intensity spectrum causes multiple interference.
For example, as one example, as shown in FIG. 1, each spectrophotometric spectrum of a plurality of types of multi-layer coated powders having different spectrophotometric characteristics simply causes multiple interference to represent a specific spectrophotometric spectrum. is there.
[0014]
Further, as another example, as shown in FIG. 2, the base particles of a plurality of types of multilayer-coated powders having different spectral photometric characteristics are a light-transmitting substance and a light-impermeable substance, respectively. When the multilayer coated powder of the kind is in contact, the multilayer coated powder based on the light-transmitting substance becomes like the light interference film of the multilayer coated powder based on the light-impermeable substance. In some cases, as if they were a single powder coated with a multilayer film, they may exhibit multiple spectrophotometric spectra due to multiple interference.
Further, as shown in FIG. 3, the base particles of a plurality of types of multilayer-coated powder having different spectral photometric characteristics are a light-transmitting substance 1 and a light-impermeable substance 2, respectively. In some cases, the film-coated powder is sparsely present and exhibits a specific spectrophotometric spectrum due to multiple interference.
By utilizing such a function to create a specific spectral spectrum and applying it to coloring, the forgery prevention, authenticity discrimination, and conspicuous effect of an object to be colored can be enhanced.
[0015]
To create a target specific spectral spectrum by using the above function, the following measures may be taken.
For example, as shown in FIG. 1, in the case of simply causing multiple spectral interferences of a plurality of types of multilayer-coated powders having different spectral photometric characteristics, the spectral photometric characteristics of each single multilayer-coated powder are determined. For reference, each spectral spectrum is combined, and color matching based on the spectral spectrum is performed and adjusted.
Further, as shown in FIG. 2, the base particles of a plurality of types of multilayer-coated powder having different spectral photometric characteristics are a light-transmitting substance 1 and a light-impermeable substance 2, respectively. When the film-coated powder is brought into contact, the light-transmitting substance 1 must be considered as including the substrate and the multilayer-coated powder as the light-impermeable substance 2 in the substrate and the multilayer-coated powder. No. That is, the substrate made of a light-transmitting substance is also treated as a light interference film. However, when a resin or the like enters between a plurality of types of multilayer film-coated powder having different spectrophotometric characteristics and affects the color, the influence of the resin is corrected and adjusted from the spectral spectrum and the computer simulation.
[0016]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, the compound and the colored product of the present invention will be described in detail.
The plurality of types of multi-layer coated powders contained in the composition of the present invention are not particularly limited as long as they have individually different spectrophotometric characteristics, and are described in, for example, WO 96/28299. And the like.
The multi-layer coating powder is obtained by adjusting each coating of the multi-layer film to a light-transmitting material such as a metal hydroxide film or a metal oxide film and adjusting the thickness of each layer of the coating film. Optionally, individual spectrophotometric characteristics can be provided.
[0017]
For example, if a coating having a different refractive index is provided on the surface of the base by a thickness corresponding to a product of the refractive index of the material of the film and the thickness of the film corresponding to a quarter of the electromagnetic wave, light is largely reflected by interference. (Fresnel reflection), and coloring can be performed by using this effect without using a dye or a pigment.
Specifically, alternate coating films having different refractive indices are formed on the surface of the substrate so that the refractive index n of the material forming the coating and one-fourth of the wavelength of visible light are satisfied so as to satisfy the following equation (1). When an alternate film having a thickness d corresponding to an integer m times is provided with an appropriate thickness and an appropriate number of films, light having a specific wavelength λ (using the interference reflection of Fresnel) is reflected or absorbed.
[0018]
nd = mλ / 4 (1)
[0019]
Utilizing this effect, a film having a film thickness and a refractive index that satisfies the formula (1) with respect to a target wavelength of visible light is formed on the surface of the base particles, and a refractive index is further formed thereon. The film having a reflection peak in the visible light region is formed by alternately repeating the coating of different films once or more. At this time, the order of the materials to be formed is determined as follows. First, when the refractive index of the substrate serving as a nucleus is high, it is preferable that the first layer is a film having a low refractive index, and when the relationship is reversed, the first layer is preferably a film having a high refractive index.
[0020]
The film thickness is measured and controlled as a reflection waveform using a spectrophotometer or the like to measure the change in the optical film thickness, which is the product of the film refractive index and the film thickness. Design the thickness. For example, when the peak position of the reflection waveform of each unit film constituting the multilayer film is precisely adjusted to a specific wavelength, a single-colored powder such as blue, green, and yellow can be obtained without using a dye or a pigment. it can.
However, in the case of an actual substrate, it is necessary to design in consideration of the particle size and shape of the substrate, the phase shift at the interface between the film material and the substrate material, the peak shift due to the wavelength dependence of the refractive index, and the like. For example, it is preferable to take into account the peak shift due to the oxide layer on the substrate surface and the peak shift due to the wavelength dependence of the refractive index.
[0021]
Also, when a metal or a substrate or a film having a large attenuation coefficient is used, a phase shift occurs, for example, the reflected light on the material surface having a large metal surface attenuation coefficient is elliptically polarized, and this interference is caused by the nuclear particle and the multilayer film. Since it affects the mutual phase of the particles, it is preferable to consider it.
Even if only the geometrical film thickness is adjusted, the peak position is shifted, so that the color becomes pale especially when coloring in a cyan color system. In order to prevent this, the effects of the phase shift on all the films are taken into consideration, and a computer simulation is designed so that the combination of the film thicknesses is optimized in advance.
Further, there is a phase shift due to the oxide layer on the substrate surface and a peak shift due to the wavelength dependence of the refractive index. In order to correct these, it is necessary to find an optimum condition using a spectrophotometer or the like so that the reflection peak becomes the target wavelength in the final target film number.
[0022]
Interference of a film formed on a curved surface such as a spherical powder occurs similarly to a flat plate, and basically follows the Fresnel interference principle. Therefore, the coloring method can be designed to a specific color system. However, in the case of a curved surface, light incident on and reflected by the powder causes complicated interference. These interference waveforms are almost the same as a flat plate when the number of films is small. However, as the number of films increases, the interference inside the multilayer film becomes more complicated. Also in the case of a multilayer film, the reflection spectral curve can be designed in advance by computer simulation based on the Fresnel interference so that the combination of film thicknesses is optimized. In particular, in the case of forming a film on the surface of the substrate particles, the effect of the phase shift on the surface of the substrate particles and all the films is taken into consideration, and a computer simulation is designed so that the combination of film thicknesses is optimized in advance. Furthermore, the peak shift due to the oxide layer on the surface of the base particles and the peak shift due to the wavelength dependence of the refractive index are taken into account. In the actual sample production, in order to correct these in the actual film by referring to the designed spectral curves, the optimum conditions are changed by changing the film thickness with a spectrophotometer or the like so that the reflection peak becomes the target wavelength with the final target film number. Must be found.
[0023]
Also, when a metal or a nuclear particle or a film having a large attenuation coefficient is used, a phase shift occurs, for example, the reflected light on the material surface having a large metal surface attenuation coefficient is elliptically polarized, and this interference is caused by the nuclear particle and the multilayer film. Since it affects the mutual phase of the particles, it is very complicated to optimize each of them and obtain the target waveform, and in order to obtain the optimal interference reflection waveform, as described above, the materials of the core particle and the multilayer film are used. And the combination of the film thickness and the film thickness at which the target waveform can be obtained must be obtained in advance by computer simulation.
In the case of coloring an irregularly shaped powder, interference by the multilayer film also occurs, and a basic film design is performed with reference to the conditions of the interference multilayer film of the spherical powder. The peak position of each unit film constituting the above-mentioned multilayer film can be adjusted by the film thickness of each layer, and the film thickness can be adjusted by the film forming conditions for forming a solid phase component such as a metal oxide on the surface of the base particles. By controlling the composition, the rate of solid phase deposition, the amount of the substrate, and the like, the film thickness can be accurately controlled, a film having a uniform thickness can be formed, and a desired color system can be obtained.
[0024]
As described above, by finding the optimum conditions while changing the film forming conditions such as the film forming solution so that the peak and valley wavelength of the reflection spectrum become the target wavelength in the final target film number, the film coating of a specific color system is obtained. Can be obtained. Further, by controlling the combination of the substances constituting the multilayer film and the thickness of each unit film, it is possible to adjust the color development due to the interference of the multilayer film. This makes it possible to vividly color the film-coated body into a desired color system without using a dye or a pigment.
Further, in order to maximize the color shift, it is necessary to optimize the sharp reflection peak wavelength and the number of peaks, and the thickness control of each layer is optimized.
[0025]
Further, the color change due to the color shift can be predicted from the calculated value of the peak position when the incident angle is changed in Expression 2 or a combination of Expression 2 and Expression 3.
In producing the film-coated powder used in the present invention, the material of the substrate, the particle diameter of the substrate particles, the number of the coating layers, the coating order of each coating layer, the material of each coating layer, and the desired reflected light wavelength are selected in advance. There is a need to.
In particular, selecting the materials of the base particles and the respective coating layers naturally specifies their refractive indices.
The specification of the refractive indices of the base particles and the respective coating layers involves calculation of the Fresnel reflection coefficient and the amplitude reflection intensity between the respective layers.
[0026]
By selecting the particle diameter of the substrate particles, the curvatures of the substrate particles and the multilayer film are specified. Unless the curvature is specified, it will be difficult to correct a spectral monitoring characteristic for film thickness monitoring described later.
By selecting the number of coating layers, R_flatParticipate in determining values.
Multilayer reflection intensity R when base particles are flat_flatIs based on the following recurrence formula 3 using the material (refractive index) of the base particles selected in advance, the number of coating layers, the coating order of each coating layer, the material (refractive index) of each coating layer, and the desired reflected light wavelength. It is determined by solving.
[0027]
(Equation 1)

[0028]
(Where R_{j + 1, j}: Amplitude reflection intensity between the j-th layer from the bottom and the layer immediately above it,
j: an integer of 1 or more (j-1 = 0 indicates a base),
i: imaginary unit,
r_{j + 1, j}: Fresnel reflection coefficient at the interface between the j-th layer from the bottom and the layer immediately above it
R_{j, j-1}: Amplitude reflection intensity between the (j-1) th layer from the bottom and the layer immediately above it,
2δ_j: Phase difference in the j-th layer from the bottom,
λ: desired reflected light wavelength,
n_j: Refractive index of the j-th layer from the bottom,
d_j: Film thickness of the j-th layer from the bottom,
φ_j: Incident angle of light to the j-th layer from the bottom. )
[0029]
Multilayer reflection intensity R obtained as described above_flatThere is no particular limitation on a method for correcting the_flatThe value is further calculated by the following equation 3.
[0030]
(Equation 2)

[0031]
(In the formula, θ: indicates the incident angle to the outermost layer)
And a method of obtaining the film thickness of each coating layer such that the R (λ) value becomes the maximum value or the minimum value at a desired wavelength is preferable.
R_flatApplying the value to the above equation 3 means that the solution of the above equation 2 is corrected by approximating the angle distribution of the light incident angle to the multilayer coated powder to the light incident angle distribution to one coated hemisphere. Means that.
When obtaining the film thickness of each coating film, it is efficient to perform the simulation by a computer.
[0032]
Next, each coating film is formed on the base particles so as to have the thickness determined as described above.
However, as described above, in the actual film-forming operation of the multilayer film-coated powder, it is impossible to directly monitor the actual film thickness until the film thickness reaches the designed value, and therefore, Monitoring of the film thickness during the film forming operation is performed by measuring, with a spectrophotometer, the wavelength at which the reflection intensity of the coated object coated with each coating layer is the maximum value or the minimum value, and the maximum or minimum reflection relative to the film thickness is measured. It is conceivable to terminate the film forming operation when the wavelength value is reached.
However, when the base material is a powder, the relationship between the maximum or minimum reflection wavelength measurement value and the film thickness occurs due to the curvature of each coating layer depending on the particle shape and particle size, and the spectrophotometer When the film is formed so that the measured maximum or minimum reflection wavelength becomes a desired value, there arises a problem that the finally obtained multilayer film-coated powder does not have a desired reflection intensity at a desired wavelength.
Therefore, correction based on the curvature of each coating layer depending on the shape and particle diameter of the base particles is required.
[0033]
The correction method is not particularly limited, but the coating layer selected on the selected base particles is coated in several steps with different film thicknesses to obtain a coating powder for particle diameter correction. Film thickness value (d_M) Is measured, and each of the film-coated powders is measured by a spectrophotometer, and the optical film thickness (nd) of each coating layer in each of the film-coating powders for particle size correction is determined. The product (nd) of the actual film thickness value of each coating layer of the correction film coating powder and the refractive index (n)_M) To the ratio of the optical film thickness (nd) of each coating layer (nd / nd)_M), And 2δ of the above recurrence formula 2 for obtaining the multilayer reflection intensity_jThe above ratio (nd / nd_MIt is preferable to correct the spectrophotometric characteristics of the powder having each coating layer by multiplying the values, and to form each coating layer so as to obtain the corrected spectrophotometric characteristics.
[0034]
The actual film thickness value (d_MThe method for measuring (2) is not particularly limited, but is preferably performed by cutting each of the particle-size-correcting film-coated powders and measuring the cut surface. Also, when cutting the film coating powder for particle size correction, it is preferable to perform the cutting by focused ion beam (FIB) processing so that the cut surface becomes clear and the actual film thickness value (d_M) Is suitable for the measurement.
[0035]
The substrate powder used for the multilayer film-coated powder is not particularly limited, but in the present invention, it is roughly classified into both a light-transmitting substance and a light-impermeable substance.
The light transmissive substance is not particularly limited as long as it transmits light. Silica, glass beads, shirasu balloon (hollow silicic acid particles), micro carbon hollow spheres (Clekasphere), Aerosil, silica micro hollow spheres , Calcium carbonate micro hollow spheres, perlite, bentonite, synthetic mica, mica such as muscovite, inorganic cellulose powder such as kaolin, cellulose acetate powder, polyamide, epoxy resin, polyester, melamine resin, polyurethane, vinyl acetate resin, silicon resin, Organic substances such as acrylic acid esters, methacrylic acid esters, styrene, ethylene, propylene and the like can be mentioned.
[0036]
The light-impermeable material is not particularly limited as long as it does not transmit light, but may be a metal such as iron, nickel, chromium, titanium, or aluminum, or a metal such as iron, nickel, chromium, titanium, aluminum, or silicon. , Calcium, magnesium, barium and other metal oxides, metal nitrides, metal carbides, metal sulfides, metal fluorides, metal carbonates, metal phosphates, etc., white carbon, calcium carbonate, perlite, talc, bentonite, kaolin And other non-metallic inorganic substances. Further, among the base particles of the light-impermeable substance, by using a magnetic substance, the composition and the colored substance of the present invention are provided with magnetism, thereby providing a magnetic toner, a magnetic ink, and a magnetically identifiable and forgery-preventing effect. Applicable as some coloring.
[0037]
Examples of the shape of the base particles used in the multilayer film-coated powder include a sphere, a subsphere state, an isotropic body such as a regular polyhedron, a rectangular parallelepiped, a spheroid, a rhombohedron, a plate-like body, and a needle-like body (a cylinder, Polyhedrons such as prisms and completely amorphous powders such as pulverized materials can also be used. In the formulation and the colored product of the present invention, when a combination of a plate-shaped substrate, a light-transmitting material and a light-impermeable material is used as the base particles, as shown in FIG. And a multilayer-coated powder based on a light-impermeable material is likely to come into contact, and acts as if it were one multilayer-coated powder. In addition, even if it is not non-contact, the multilayer coated powder is arranged using a medium, the concentration of the multilayer coated powder is adjusted, the lamination state of the powder, the number of layers, and the like are considered. State.
[0038]
Further, the particle size of these substrates is not particularly limited, but is preferably in the range of 0.01 μm to several mm.
The specific gravity of the substrate particles is in the range of 0.1 to 10.5. However, when the obtained powder is used by dispersing it in a liquid or the like, the fluidity and the buoyancy may be reduced. To 0.1 to 5.5, more preferably 0.1 to 2.8, and still more preferably 0.5 to 1.8. When the obtained powder is used by dispersing it in a liquid or the like, if the specific gravity of the substrate is less than 0.1, the buoyancy in the liquid is too large, and it is necessary to make the film multilayer or very thick, which is uneconomical. . On the other hand, when it exceeds 10.5, the film for floating becomes thick, which is also uneconomical.
[0039]
In the multilayer film-coated powder used in the composition and the colored material of the present invention, as described above, the powder substrate particles are formed of a plurality of film layers having different refractive indexes, and the refractive index and the layer of each film layer are used. By appropriately selecting the thickness and coating the powder, it is possible to obtain a powder colored in a specific color system by the interference color and exhibiting a color shift.
The method for forming such a multilayer film is not particularly limited, and includes a method by hydrolysis of a metal alkoxide described in International Publication WO 96/28299. Since an organic solvent, which is a product, is used as a reaction solvent, it is necessary to provide explosion-proof equipment as a film-forming apparatus, resulting in an overall high cost. From such a viewpoint, in recent years, an aqueous film-forming method for depositing a metal hydroxide film or a metal oxide film on the surface of base particles by a reaction of a metal salt without using an organic solvent has been disclosed in JP-A-11-131102. And the like. In this aqueous film forming method, a buffer solution is used as a solvent for a solid phase deposition reaction, and a solid phase is deposited at a certain pH and at an appropriate speed.
[0040]
In the film forming method, the metal used as the metal salt includes iron, nickel, chromium, titanium, zinc, aluminum, cadmium, zirconium, silicon, tin, lead, lithium, indium, neodymium, bismuth, cerium, antimony and the like. Other examples include calcium, magnesium, barium and the like. Examples of the salts of these metals include salts of sulfuric acid, nitric acid, hydrochloric acid, oxalic acid, carbonic acid and carboxylic acid. Furthermore, a chelate complex of the metal is also included. As the kind of the metal salt used in the preparation of the film-coated powder, a suitable metal salt is selected according to the property to be imparted to the surface of the substrate and the means applied in the production.
[0041]
The multi-layer coating powder used in the composition and the coloring material of the present invention basically forms a colorless and transparent film, and laminates films having different refractive indices to color. However, if the waveform of the reflection and absorption spectrum does not become the desired color only by coloring due to interference, the following metal cobalt, yttrium, sulfur, europium, dysprosium, antimony, samarium, copper, It is preferable to use salts of metals such as silver, gold, platinum, rhodium, iridium, tungsten, iron, and manganese, such as sulfuric acid, nitric acid, hydrochloric acid, oxalic acid, carbonic acid, and carboxylic acid. Further, a chelate complex of the metal is also preferable. The content of these metals in the film is 10 ppm to 15%, preferably 10 ppm to 15%, and more preferably 50 ppm to 5%.
When the content of these metals is small, the coloring becomes insufficient, and when the content is too large, the coloring becomes too strong to give a dark color, and there is a disadvantage that a powder of a bright color cannot be obtained.
[0042]
A film of a metal oxide or the like using these metal salts may be formed in a plurality of layers, and a metal oxide or the like obtained by hydrolysis of a metal alkoxide, if necessary, on the film of the metal oxide or the like. A film can be formed by a film forming method.
In this way, a multilayer film can be formed on the substrate particles, and at this time, by setting the formation conditions so that the thickness of each layer has a predetermined thickness, the desired characteristics can be obtained. Obtainable. In addition, a film of a metal oxide or the like can be formed in multiple layers by a simple operation using a metal salt which is an inexpensive raw material. In particular, it is an important advantage that a powder coated with a multilayer film can be obtained without using an expensive metal alkoxide as a raw material.
[0043]
In the method of producing the multilayer coating powder used in the composition and the coloring material of the present invention, the multilayer coating may be manufactured as a continuous process, or each coating may be manufactured one by one, or It can be manufactured by various methods such as a combination of a single-layer manufacturing and a multi-layer continuous manufacturing.
The particle size of the multi-layer coating powder used for the compound and the coloring matter in the present invention is not particularly limited, and can be appropriately adjusted depending on the purpose, and is usually preferably 0.1 μm to several mm, more preferably Preferably it is in the range of 0.1 μm to 30 μm.
[0044]
The preferred range of the thickness of one layer of the multilayer film-coated powder used in the composition and the coloring matter of the present invention varies depending on the film material and the size of the base particles. When the film substance is a substance having a large absorption coefficient such as a metal or an opaque metal oxide or a metal sulfide, 0.00001 μm to 0.5 μm when the substrate particles are 0.1 μm to 1 μm, and 0.1 μm when the substrate particles are 1 μm to 10 μm. 001 μm to 0.7 μm, and preferably 0.001 μm to 1.0 μm when the base particles are 10 μm or more.
When the film material has a small absorption coefficient, such as a transparent oxide, the base particles are 0.01 μm to 1.5 μm when the base particles are 0.1 μm to 1 μm, and 0.01 μm to 3.0 μm when the base particles are 1 μm to 10 μm. When the size of the base particles is 10 µm or more, the thickness is preferably 0.01 µm to 5.0 µm.
Further, the preferable thickness range of the total film thickness of the multilayer film-coated powder used in the compound and the colored material of the present invention also varies depending on the size of the particles serving as the base. When the base particles are 0.1 μm to 1 μm, the thickness is preferably 0.1 μm to 5 μm, when the base particles are 1 μm to 10 μm, 0.1 μm to 8 μm, and when the base particles are 10 μm or more, the thickness is preferably 0.1 μm to 20 μm.
[0045]
The multilayer film-coated powder used for the composition and the colored material of the present invention is, as described above, a film-forming reaction in the production method, particularly when a film-forming reaction is performed in an aqueous solvent, as a film-forming reaction solvent. The film coating reaction is formed by a film forming reaction on the surface of the substrate under an ultrasonic dispersion condition using an aqueous solvent at a constant pH.
In the preparation of the above-mentioned multilayer film-coated powder, a buffer solution is added to an aqueous solvent to make a buffer solution, or a buffer solution prepared in advance is used in order to keep the film-forming reaction constant. At the time of the film formation reaction, a film material other than the buffer solution is added to form a film. If the pH fluctuates greatly when the film is formed by adding the film forming raw material, it is desirable to add a buffer solution in order to prevent this from fluctuating.
The term “constant pH” as used in the present invention means that the pH is within ± 2, preferably ± 1, more preferably ± 0.5 of a predetermined pH.
[0046]
Various systems are used for the buffer solution, and there is no particular limitation. First, it is important that the base particles can be sufficiently dispersed, and at the same time, metal hydroxide or metal oxide film-coated powder deposited on the surface of the base is also used. It is selected so as to satisfy the conditions that can be dispersed by the action of the electric double layer and that a dense film can be formed by the above-mentioned gentle dropping reaction.
The buffer solution used for the film-forming reaction depends on the solid phase component to be precipitated, and is not particularly limited. However, Tris, boric acid, glycine, succinic acid, lactic acid, acetic acid, tartaric acid, Hydrochloric acid and the like can be mentioned.
[0047]
Next, as an example, a method for forming an alternating multilayer film of a metal oxide having a high refractive index and a metal oxide having a low refractive index, particularly when a film forming reaction is performed in an aqueous solvent, will be specifically described. First, when forming a coating such as titanium oxide or zirconium oxide, the base particles are immersed in a buffer solution such as an acetic acid / sodium acetate system, dispersed by ultrasonic oscillation, and titanium sulfate, which is a metal salt such as titanium or zirconium. And zirconium sulfate or the like as a raw material, an aqueous solution of these metal salts is slowly dropped into the reaction system, and the resulting metal hydroxide or metal oxide is deposited around the base particles. During this dropping reaction, the pH is maintained at the pH of the buffer solution (5.4).
After completion of the reaction, the powder is subjected to solid-liquid separation, washed and dried, and then subjected to a heat treatment. The drying means may be either vacuum drying or natural drying. Further, it is also possible to use a device such as a spray dryer in an inert atmosphere.
When the film to be coated is titanium oxide, the formation of titanium oxide is represented by the following reaction formula.
[0048]
Ti (SO₄)₂+ 2H₂O → TiO₂+ 2H₂(SO₄  )
[0049]
Titanyl sulfate TiO₂The content is preferably 5 g / l to 180 g / l, more preferably 10 g / l to 160 g / l. If the amount is less than 5 g / l, it takes too much time to form a film, and the amount of powder to be treated is reduced, which is uneconomical. If the amount exceeds 180 g / l, the diluting solution is hydrolyzed during the addition and does not become a film forming component. Are both unsuitable.
[0050]
Subsequently, when forming a film such as silicon dioxide or aluminum oxide, KCl / H₃BO₃The above titania-coated particles are immersed and dispersed in a buffer solution in which NaOH is added to a system or the like, and a metal salt of silicon or aluminum, such as sodium silicate or aluminum chloride, is used as a raw material, and an aqueous solution of these metal salts is reacted. It can be carried out by slowly dropping the solution into the system and depositing the generated metal hydroxide or metal oxide around the base particles. During this dropping reaction, the pH is maintained at the pH of the buffer solution (9.0).
After completion of the reaction, the powder is subjected to solid-liquid separation, washed and dried, and then subjected to a heat treatment. By this operation, by repeating the operation of forming two layers of metal oxide films having different refractive indexes on the surface of the base particles, a powder having a multilayer metal oxide film on the surface is obtained.
When the film to be coated is silicon dioxide, the formation of silicon dioxide is represented by the following reaction formula.
[0051]
Na₂Si_XO_{2X + 1}+ H₂O → XSiO₂+ 2Na⁺+ 2OH⁻
[0052]
The multilayer film-coated powder composition of the present invention may contain only a plurality of types of multilayer film-coated powders having different spectrophotometric characteristics. Preferably it is in the form of a composition.
Representative examples of the color material composition include (1) each specific color ink or paint-like composition (fluid) and (2) each specific color toner, each specific color dry ink-like composition (powder), and the like. There is. These will be described below.
[0053]
(1) As a medium (vehicle) of the specific color ink or the paint-like composition (fluid), a conventionally known varnish used for color printing, color magnetic printing, and color magnetic paint can be used. For example, a liquid polymer, a polymer or a monomer dissolved in an organic solvent, and the like can be appropriately selected and used depending on the type of powder, the method of applying the ink, and the application.
[0054]
Examples of the liquid polymer include dienes such as polypentadiene and polybutadiene, polyethylene glycols, polyamides, polypropylenes, waxes, and modified copolymers thereof.
Polymers soluble in organic solvents include olefin polymers, acrylic resins such as oligoester acrylates, polyesters, polyamides, polyisocyanates, amino resins, xylene resins, ketone resins, diene resins. And rosin-modified phenolic resins, diene rubbers, chloroprene resins, waxes, and modified products and copolymers thereof.
Examples of the monomer soluble in the organic solvent include styrene, ethylene, butadiene, propylene and the like.
Examples of the organic solvent include alcohols such as ethanol, isopropanol and normal propanol, ketones such as acetone, benzene, toluene, xylene, kerosene, benzene hydrocarbons, esters, ethers, and modified products and copolymers thereof. Can be mentioned.
[0055]
(2) The specific color-based toner, the specific color-based dry ink, and the specific color-based dry paint-like composition (powder) are obtained by mixing a plurality of types of multi-layer coating powders having different spectrophotometric characteristics with a resin or as required. Directly kneading the toning material with a screw type extruder, roll mill, kneader, etc., coarsely pulverizing with a hammer mill, cutter mill, finely pulverizing with a jet mill, etc., and classifying to the required particle size with an elbow jet etc. Thus, a powdery cyan color material composition can be obtained. In addition, a powdery specific color coating composition can be obtained by using a polymerization method such as an emulsion polymerization method or a suspension polymerization method.
Furthermore, the multi-layer coating powder, resin, additives such as a toning agent, and a solvent may be liquefied by a colloid mill or a three-roll mill to obtain a liquid specific color paint composition such as an ink paint.
[0056]
Examples of the toning material for increasing the brightness include white pigments (painting materials), such as titanium oxide, zinc oxide, tin oxide, silicon oxide, antimony oxide, lead oxide, and composite oxides thereof, and Calcium carbonate, magnesium carbonate, carbonates such as barium carbonate, or barium sulfate, sulfates such as calcium sulfate, sulfides such as zinc sulfate or composite oxides obtained by sintering the oxides and carbonates and sulfates, Complex hydrated oxides are included.
[0057]
In order to adjust saturation and hue, especially when used for color reproduction with full color mixture, as a toning material, a blue pigment (organic dye / pigment) such as alkali blue lake, peacock lake, peacock lake blue, etc. Lake dyes and lake pigments, oil dyes such as oil blue, alcohol dyes such as alcohol blue, phthalocyanine pigments such as phthalocyanine and copper phthalocyanine, (inorganic pigments) oxide sulfide composite pigments such as ultramarine, iron blue, Copper-based ultramarine blue pigments such as Millory Blue, cobalt oxide-based composite oxides such as Cobalt Blue and Cerulean Blue, blue pigments, blue-based organic dyes and pigments, and blue inorganic pigments Lake dyes such as alkali blue lake and peacock blue lake, lakes Pigments such as metal-free phthalocyanine and copper phthalocyanine Chrome-based oxides and hydrated oxides such as chrome green, zinc green, chromium oxide, and hydrated chromium (viridian), which are tarocyanine-based dyes and green pigments, copper-based oxides such as emerald green, and cobalt-based oxides such as cobalt green Pigments, nitroso pigments such as pigment green and naphthol green, azo pigments such as green gold, phthalocyanine pigments such as phthalocyanine green and polychrome copper phthalocyanine, lakes such as malachite green lake and acid green lake, oils Organic dyes and pigments such as oil dye pigments such as green and oil dye pigments and alcohol dye pigments such as alcohol blue are exemplified. However, the present invention is not limited only to these.
[0058]
Further, when it is necessary to perform toning using pigments or dyes such as blue, yellow and magenta in delicate color tone control, it is preferable to add these pigments to obtain an optimum specific color.
In the case of this specific color coating composition, (a) the resin produced by the above-mentioned pulverization method is not particularly limited, but polyamide, epoxy resin, polyester, melamine resin, polyurethane, vinyl acetate resin, Examples thereof include a polymer or a copolymer of a silicon resin, an acrylate, a methacrylate, styrene, ethylene, butadiene, propylene and a derivative thereof.
(B) In the case of the polymerization method, polymerization is started from one or a mixture of ester, urethane, vinyl acetate, organic silicon, acrylic acid, methacrylic acid, styrene, ethylene, butadiene, propylene and the like, and the polymer or These copolymers are formed.
[0059]
As typical examples of the color material composition comprising the multilayer film-coated powder composition of the present invention, as described above, (1) each specific color ink or paint-like composition (fluid) and (2) each specific color And a specific color-based dry ink-like composition (powder).
In the case of fluid, it is a specific color ink, paint, etc., the toning material, a resin that is slow drying, a solidification accelerator, a thickener to increase the viscosity, a fluidization to reduce the viscosity. A component such as a dispersant can be included for dispersing the agent and the particles.
On the other hand, in the case of powder, (a) when powder is produced by a pulverization method, a solidification accelerator is used for the toning material and a resin that is slowly dried, and a fluidizing agent is used for reducing viscosity during kneading. In order to disperse the agent and the particles, components such as a dispersant, a charge controlling agent for fixing to paper or the like, and a wax can be included.
(B) When a polymerization method is used, the above-mentioned toning material, polymerization initiator, polymerization accelerator, thickener to increase the viscosity, dispersant to disperse the particles, fixing to paper, etc. And components such as a wax and a charge control agent.
The multi-layer coated powder formulation is applicable to wet and dry color printing, wet and dry color magnetic printing, visible light, invisible light (ultraviolet and infrared), fluorescent coloring and magnetism, and electric (electric field). ) Can be applied to other uses that require a security function, such as a color magnetic ink for preventing forgery of printed matter.
[0060]
Each said specific color ink or paint-like composition or each specific color toner, each specific color dry ink-like composition, each specific color dry paint composition, printed on a substrate, melt-transferred or coated on When applied, the relationship between the content of the powder coated with the multilayer film and the resin in the coating composition is 1: 0.5 to 1:15 in volume ratio. If the content of the medium is too small, the applied film does not adhere to the object to be coated. On the other hand, if the amount is too large, the color of the pigment becomes too light and cannot be called a good ink or paint.
In addition, the relationship between the amount of the solvent and the total amount of each color material and resin in each color ink or coating composition is 1: 0.5 to 1:10 by volume ratio, and the amount of the solvent is small. If it is too long, the viscosity of the paint is too high to apply uniformly. On the other hand, if the amount of the solvent is too large, it takes time to dry the coating film, and the efficiency of the coating operation is extremely reduced.
[0061]
In addition, the color density of a coating film when printing, melt-transferring, or applying a coating material to an object to be coated is determined by the amount of pigment per unit area of the object to be coated. The amount of the multilayer film-coated powder on the object after the paint is dried is 0.1 to 300 g per square meter, preferably 0.1 to 100 g, in terms of area density when uniformly applied. Good paint color can be obtained. If the area density is smaller than the above value, the ground color of the object to be coated appears, and if the area density is larger than the above value, the color density of the coating color does not change, which is uneconomic. That is, even if the pigment is placed on the object to be coated to a certain thickness or more, the light does not reach the pigment on the lower side of the coating film. It is uneconomical to make the coating film thicker than such a thickness, because the coating thickness exceeds the hiding power of the coating material, and the coating effect is not obtained. However, this is not the case when thick coating is performed because the thickness of the coating film is reduced in consideration of the abrasion of the coating film. Also, this is not limited to the case where a specific design or the like is partially formed.
[0062]
It should be noted that the multilayer film-coated powder composition of the present invention and a coloring material using the same can also be provided with fluorescent coloring properties.
The application method is not particularly limited, but a method of further providing a coating layer containing a fluorescent substance as described in JP-A-2000-87103 on a multilayer film-coated powder, or a method of providing a color-shifting powder and a fluorescent substance To form a coloring material composition.
[0063]
【Example】
Hereinafter, the present invention will be described more specifically with reference to Examples, but it is needless to say that the scope of the present invention is not limited thereto.
[Example 1]
1. Preparation of raw material solution
(Adjustment of buffer solution A)
The buffer solution A was adjusted at the following solution concentration.
A solution C was prepared by dissolving 0.4 mol of potassium chloride and 0.4 mol of boric acid in 1 liter of deionized water.
Solution B was prepared by dissolving 0.4 mole of sodium hydroxide in 1 liter of deionized water.
115 g of the solution C was mixed and homogenized with 250 g of the solution B to obtain a buffer solution A.
[0064]
(Adjustment of buffer B)
The buffer solution B was adjusted at the following solution concentration.
Solution D was obtained by dissolving 29.8 g of potassium chloride and 24.7 g of boric acid in 1 liter of deionized water.
Next, 16.0 g of sodium hydroxide was dissolved in 16 g of deionized water and 1 liter of deionized water to obtain a solution E.
200 g of the solution D and 80 g of the solution E were mixed to prepare a buffer B.
[0065]
(Adjustment of sodium silicate aqueous solution)
The aqueous solution of sodium silicate was prepared with the following composition.
Sodium silicate is gradually added to deionized water to homogenize₂The solution had a content of 10% (hereinafter referred to as "silicic acid solution").
(Preparation of titania dripping liquid)
The titania dropping solution was prepared with the following composition.
133 g of a 20% aqueous solution of titanium chloride [III] was mixed with 273 g of 28% aqueous ammonia and 133 g of hydrogen peroxide to obtain a peroxotitanic acid solution (hereinafter referred to as "titanium solution").
[0066]
2. Preparation of opaque polychromatic magnetic powder (powder changing from magenta to green)
(Formation of First Layer Silica Film)
100 g of plate-shaped permalloy powder (average particle size: 21 μm) (manufactured by Fukuda Foil Powder Co., Ltd.) was added to 2,800 g of buffer solution A prepared in advance, and the mixture was sufficiently stirred and suspended.
While stirring the powder suspension solution in a water bath at 30 ° C. and stirring at 1000 rpm with a stirrer, 1400 g of an aqueous solution of sodium silicate was added dropwise at 26.7 ml / min. A silica film was gradually formed on the powder surface.
After the completion of the reaction, the slurry containing the silica film powder was repeatedly decanted with sufficient water and washed.
After the washing, for the second time, the silica membrane powder was added to 2,800 g of the buffer solution A prepared in advance, and the suspension was sufficiently stirred and suspended. While stirring the powder suspension solution in a water bath at 30 ° C. and stirring at 1000 rpm with a stirrer, 1400 g of an aqueous solution of sodium silicate was added dropwise at 26.7 ml / min. A silica film was gradually formed on the powder surface.
After washing, solid-liquid separation was performed by sedimentation, the solid content was spread on a vat, and dried at 120 ° C. for 8 hours using a drier.
The obtained dried powder was heat-treated in a rotary tube furnace at 650 ° C. for 30 minutes in a nitrogen atmosphere to obtain a silicon oxide-coated powder A1.
[0067]
(Formation of second layer titanium oxide film)
100 g of silicon oxide-coated powder A1, 100 g was sufficiently suspended in 4,200 ml of buffer B, and the temperature was maintained at 30 ° C. in a 28 kHz, 600 W ultrasonic bath equipped with a temperature controller, and ultrasonic waves were applied. While stirring with a stirrer, 1352 g of titania dropping solution was dropped at 15 ml / min, and after the dropping, the mixture was kept for 2 hours to gradually form a titanium oxide film on the surface of the powder.
After the completion of the reaction, the slurry containing the silica film powder was repeatedly decanted with sufficient water and washed.
After washing, solid-liquid separation was performed by sedimentation, the solid content was spread on a vat, and dried at 120 ° C. for 8 hours using a drier.
The obtained dried powder was subjected to a heat treatment in a rotary tube furnace at 650 ° C. in a nitrogen atmosphere for 30 minutes to obtain a silicon oxide-titanium oxide coated powder A2.
[0068]
(Formation of Third Layer Silica Film)
To 2,800 g of the buffer solution A prepared in advance, 100 g of the silicon oxide-titanium oxide-coated powder A2 was added, and the mixture was sufficiently stirred and suspended.
While stirring the powder suspension solution in a water bath at 30 ° C. and stirring at 1000 rpm with a stirrer, 1400 g of an aqueous solution of sodium silicate was added dropwise at 26.7 ml / min. A silica film was gradually formed on the powder surface.
After the completion of the reaction, the slurry containing the silica film powder was repeatedly decanted with sufficient water and washed.
After the washing, for the second time, 2800 g of buffer solution A prepared in advance was added, and the mixture was sufficiently stirred and suspended. While holding the powder suspension solution in a water bath at 30 ° C. and stirring at 1000 rpm with a stirrer, 1320 g of an aqueous solution of sodium silicate was added dropwise at 26.7 ml / min. A silica film was gradually formed on the powder surface.
After washing, solid-liquid separation was performed by sedimentation, the solid content was spread on a vat, and dried at 120 ° C. for 8 hours using a drier.
The obtained dried powder was heat-treated in a rotary tube furnace at 650 ° C. in a nitrogen atmosphere for 30 minutes to obtain a silicon oxide-titanium oxide-silicon oxide-coated powder A3.
[0069]
3. Preparation of coated paper
16 g of the obtained silicon oxide-titanium oxide-silicon oxide-coated powder A3 was kneaded into 10 ml of a 10% aqueous solution of polymethacrylamine to obtain an ink-like composition LA.
The ink-like composition was applied to coated paper with a bar coater, and dried to obtain a coated paper CP1. Looking at the color, the color from the front was blue, the color became reddish purple when tilted at 45 degrees, and the color viewed further tilted was dark brown.
[0070]
4. Production of transparent interference powder
(Formation of titanium oxide film)
220 g of muscovite (average particle size: 21 μm) (manufactured by REPCO) was added to 4,200 ml of buffer B, and the temperature was kept at 30 ° C. in a 28 kHz, 600 W ultrasonic bath with a temperature controller. While stirring with a stirrer, 1352 g of a titania dropping solution was dropped at 15 ml / min, and the solution was kept for 2 hours after dropping, and a silica film was gradually formed on the powder surface.
After the completion of the reaction, the slurry containing the silica film powder was repeatedly decanted with sufficient water and washed.
After washing, solid-liquid separation was performed by sedimentation, the solid content was spread on a vat, and dried at 120 ° C. for 8 hours using a drier.
The obtained dry powder was heat-treated in a rotary tube furnace at 500 ° C. for 30 minutes in a nitrogen atmosphere to obtain a titanium oxide-coated powder B.
[0071]
5. Preparation of coated paper
16 g of the obtained silicon oxide-titanium oxide coated powder A3 was kneaded into 10 ml of a polymethacrylamine aqueous solution to obtain an ink-like composition LB1.
The ink-like composition LB1 was coated on a coated paper with a bar coater, and dried to obtain a coated paper CP2.
12 g of the titanium-coated powder B was kneaded into 10 ml of a 10% aqueous solution of polymethacrylamine to obtain an ink-like composition LB2. After drying the ink-like composition LB2, the coated paper CP2 was further coated with a bar coater to obtain a coated paper CP3 after drying.
Looking at the color of CP3, the color from the front was yellow-green, blue when tilted by 45 degrees, and red-violet when viewed further tilted. 3 above. CP3 changed color more vividly than the coated paper CP1 prepared in the above.
[0072]
6. Formation of thin film material 1
10 g of the film-coated powder A3 whose substrate is a light-impermeable physical property is sufficiently dispersed in 500 ml of an alcohol solution in which 0.5 g of an acrylic resin is dissolved, and the bottom surface is 200 square centimeters in width and 5 cm in depth. The mixture was uniformly settled. After all the powder settled, the liquid was sucked out with a suction machine and dried at 60 ° C. for 12 hours. The dried product was a thin film A1.
After drying, 10 g of the film-coated powder B whose substrate is a light-transmitting substance is sufficiently dispersed and poured into 500 ml of an alcohol solution in which 0.5 g of an acrylic resin is dissolved, and the powder is completely poured into the container in which the thin film is formed. After the precipitation, it was dried at 60 ° C. for 12 hours. The dried product was a thin film 1B.
As a result, this thin film-like substance has remarkable polychromaticity. Further, when the color of this thin film 1B is viewed, the color from the front is yellow-green, the color becomes yellow when it is inclined by 45 degrees, and the color when further inclined. Was purplish red. The magnetism of the thin film is 31 Am²/ Kg (magnetic field of 790 kA / m).
[0073]
7. Formation of thin film substance 2
10 g of the film-coated powder A3 whose base is a light-impermeable physical property and 10 g of the film-coated powder B whose base is a light-transmissive substance are sufficiently dispersed in 500 ml of an alcohol solution in which 0.5 g of an acrylic resin is dissolved. A 200 cm2, 5 cm deep bottom was evenly placed in a square plastic container and settled. After all the powder settled, the liquid was sucked out with a suction machine and dried at 60 ° C. for 12 hours.
When this thin film is observed with a microscope, the film-coated powder A3 in which the substrate having a high specific gravity is a light-impermeable substance first settles out to form a layer, and the substrate having a low specific gravity is subsequently a film-coated powder in which the substrate having a low specific gravity is a light-transmissive substance The body B had a double structure with sedimentation.
This thin film material 2 has remarkable polychromaticity, and the color of the thin film material 2 from the front is yellow-green, becomes blue when tilted by 45 degrees, and becomes reddish purple when viewed further. there were. The magnetic properties of the thin film are 33 Am²/ Kg (magnetic field of 790 kA / m).
It is difficult to produce such interference colors using only a single type of interference particle, and it is considered that a more complex forgery prevention effect can be obtained by applying multiple interference of a plurality of particles.
In this case, by arranging the opaque interference powder containing the magnetic substance in the lower layer, the effect that the reflected color can be made clearer by the absorption of the magnetic powder was also recognized.
[0074]
Example 2 (polychromaticity due to spherical powder orientation)
In order to use the spherical powder as the permeable particles, a film was formed. The buffer solution and the film forming raw materials used were the same as in Example 1.
(Formation of First Layer Silica Film)
500 g of glass beads (UB13 manufactured by Union) were added to 2,800 g of the buffer solution A prepared in advance, and the mixture was sufficiently stirred and suspended.
While stirring the powder suspension in a water bath at 30 ° C. and stirring at 1000 rpm with a stirrer, 1400 g of an aqueous solution of sodium silicate was dropped at 26.7 ml / min, and after dropping, held for 2 hours. A silica film was gradually formed on the powder surface.
After the completion of the reaction, the slurry containing the silica film powder was repeatedly decanted with sufficient water and washed.
For the second time after washing, 2,800 g of buffer solution A prepared in advance was added, and the mixture was sufficiently stirred and suspended. While stirring the powder suspension in a water bath at 30 ° C. and stirring at 1000 rpm with a stirrer, 1400 g of an aqueous solution of sodium silicate was dropped at 26.7 ml / min, and after dropping, held for 2 hours. A silica film was gradually formed on the powder surface.
As the third time after washing, 2,800 g of buffer solution A prepared in advance was added, and the mixture was sufficiently stirred and suspended. While stirring the powder suspension solution in a water bath at 30 ° C. and stirring at 1000 rpm with a stirrer, 1400 g of an aqueous solution of sodium silicate was added dropwise at 26.7 ml / min. A silica film was gradually formed on the powder surface.
After washing, solid-liquid separation was performed by sedimentation, the solid content was spread on a vat, and dried at 120 ° C. for 8 hours using a drier.
The obtained dried powder was heat-treated in a rotary tube furnace at 650 ° C. for 30 minutes in a nitrogen atmosphere to obtain a silicon oxide-coated powder C1.
[0075]
(Formation of the second layer titanium oxide film)
300 g of silicon oxide-coated powder C1, 300 g was sufficiently suspended in 4,200 ml of buffer B, and the temperature was maintained at 30 ° C. in a 28 kHz, 600 W ultrasonic bath equipped with a temperature controller. While stirring with a machine, 1352 g of titania dropping solution was dropped at 15 ml / min, and the solution was kept for 2 hours after dropping, and a titanium oxide film was gradually formed on the powder surface.
After the completion of the reaction, the slurry containing the titanium oxide film-forming powder was repeatedly decanted with sufficient water and washed.
After washing, solid-liquid separation was performed by sedimentation, the solid content was spread on a vat, and dried at 120 ° C. for 8 hours using a drier.
The obtained dried powder was subjected to a heat treatment in a rotary tube furnace at 650 ° C. for 30 minutes in a nitrogen atmosphere to obtain a silicon oxide-titanium oxide coated powder C2.
This powder had peaks at 435 nm, 553 nm, and 687 nm, and had a light pink surface color.
[0076]
(Preparation of coated paper)
16 g of the magnetic powder A3 powder obtained in Example 1 was kneaded into 15 ml of a 10% aqueous solution of polymethacrylamine to obtain an ink-like composition LD1.
The ink-like composition LD1 was coated on a coated paper with a bar coater, and dried to obtain a coated paper CP4.
9 g of the powder C2 of Example 2 was further kneaded into 15 ml of a 10% aqueous solution of polymethacrylamine on the coating CP4 to obtain an ink-like composition LE.
The ink-like composition LE was applied to the coated paper CP4 with a bar coater, and after drying, the color of the coated paper CP5 was reddish purple when viewed from the front, and changed to yellow and green as the color was inclined.
This color change is considered to be due to multiple interference between the spherical coated powder and the plate-like powder.
[Brief description of the drawings]
FIG. 1 is a conceptual diagram showing an example of an estimation mechanism that causes multiple interference in a spectrophotometric spectrum of a powder contained in a multilayer film-coated powder composition of the present invention.
FIG. 2 is a conceptual diagram showing another example of an estimation mechanism that causes multiple interference in a spectrophotometric spectrum of a powder contained in a multilayer film-coated powder composition of the present invention.
FIG. 3 is a conceptual diagram showing another example of an estimating mechanism that causes multiple interference of a spectrophotometric spectrum of a powder contained in a multilayer film-coated powder composition of the present invention.
[Explanation of symbols]
1 light transmissive substance
2 Light-impermeable material

Claims (6)

A composition containing a plurality of types of multilayer-coated powders having different spectrophotometric characteristics. 2. The composition according to claim 1, wherein the powder coated with the multilayer film contains at least both a substance whose base particles are a light-transmitting substance and a substance which is a light-impermeable substance. 3. The composition according to claim 2, wherein the light-impermeable substance is a magnetic substance as the multilayer-coated powder. A colored material which is colored with a composition containing a plurality of types of multilayer film-coated powders having different spectrophotometric characteristics. 5. The colored product according to claim 4, wherein at least both the base particle of which is a light-transmitting substance and the base particle of which is a light-impermeable substance are used as the multilayer film-coated powder. 6. The colored material according to claim 5, wherein the light-impermeable material of the multilayer film-coated powder is a magnetic material.

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