JP3773220B2 - Titanium dioxide pigment and method for producing the same - Google Patents
Titanium dioxide pigment and method for producing the same Download PDFInfo
- Publication number
- JP3773220B2 JP3773220B2 JP30366696A JP30366696A JP3773220B2 JP 3773220 B2 JP3773220 B2 JP 3773220B2 JP 30366696 A JP30366696 A JP 30366696A JP 30366696 A JP30366696 A JP 30366696A JP 3773220 B2 JP3773220 B2 JP 3773220B2
- Authority
- JP
- Japan
- Prior art keywords
- titanium dioxide
- dioxide pigment
- slurry
- coating
- pigment
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired - Lifetime
Links
Classifications
-
- C—CHEMISTRY; METALLURGY
- C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
- C09C—TREATMENT OF INORGANIC MATERIALS, OTHER THAN FIBROUS FILLERS, TO ENHANCE THEIR PIGMENTING OR FILLING PROPERTIES ; PREPARATION OF CARBON BLACK ; PREPARATION OF INORGANIC MATERIALS WHICH ARE NO SINGLE CHEMICAL COMPOUNDS AND WHICH ARE MAINLY USED AS PIGMENTS OR FILLERS
- C09C1/00—Treatment of specific inorganic materials other than fibrous fillers; Preparation of carbon black
- C09C1/36—Compounds of titanium
- C09C1/3607—Titanium dioxide
- C09C1/3653—Treatment with inorganic compounds
- C09C1/3661—Coating
Landscapes
- Chemical & Material Sciences (AREA)
- Organic Chemistry (AREA)
- Inorganic Compounds Of Heavy Metals (AREA)
- Pigments, Carbon Blacks, Or Wood Stains (AREA)
- Paints Or Removers (AREA)
Description
【０００１】
【産業上の利用分野】
本発明は、水性分散体用の二酸化チタン顔料及びその製造方法に関する。
【０００２】
【発明の技術的背景】
塗料分野においては、地球環境の安全や作業環境の安全、衛生面、さらには省資源化などへの対応ともあいまって、水性溶媒系塗料への指向が一層強まってきている。
【０００３】
ところで、水性溶媒系塗料、とりわけエマルション塗料は、常乾型のものが多く、また臭気、火気への安全性に優れ、かつ塗装作業性が良好であるなど多くの特長を有しているところから、今日、工業用や家庭用の塗料として種々の適用分野において多量に使用されている。
【０００４】
しかして、エマルション塗料は、基本的には主要構成成分であるビヒクルの合成樹脂エマルションに顔料を配合、分散させたものであるが、この分散過程で強い機械的衝撃を受けるとエマルション系が破壊されて安定性を失い易く、溶剤型ビヒクル系塗料のように強力な剪断力下での分散処理が困難である場合が少なくない。このため通常、種々の分散剤や増粘剤などの存在下に水性媒体中に二酸化チタン顔料のほか、体質顔料などを懸濁、分散させて高濃度顔料スラリーを調製し、該顔料スラリーを樹脂エマルションに添加して塗料化することが行なわれている。
【０００５】
【発明が解決しようとする課題】
しかしながら、前記分散剤は、分散作業性を改善する上で有用なものではあるが、反面例えば塗膜の耐水性などの塗膜物性を損なったり、また二酸化チタン顔料の分散性付与には有用であっても体質顔料の分散性を損ない易かったりするなど、改善を要する問題点も少なくない。このため分散剤の不存在下もしくは添加量を極力少なくし得るような易分散性顔料、とりわけ主要構成成分である二酸化チタン顔料について強く希求されている。
【０００６】
【課題を解決するための手段】
本発明者等は、予てより前記問題点について、二酸化チタン顔料の粒子表面を金属の含水酸化物や酸化物で変成処理することによってその解決を図るべく前記処理について詳細に検討を進めた結果、意外にも、互いに沈殿物の形態が異なるシリカ被覆層のみを特定の順序で二酸化チタン顔料の粒子表面に存在させることによって、（1)エマルション塗料系における分散作業性に極めて優れた高顔料濃度の二酸化チタン顔料水性分散体を容易に得ることができること、（2)前記（1)の高顔料濃度の二酸化チタン顔料水性分散体を用いて塗料化してなるエマルション塗料は、優れた隠蔽性能や耐水性能などの塗膜性能を付与し得るとともに、いわゆるグロスエマルション系において優れた光沢性を有する塗膜性能を付与し得ること、さらの（3)シリカ被覆処理工程で惹起し易い処理スラリーやケーキのチキソトロピック粘性による取扱い作業の困難性や生産効率の低下などを実質的に回避し得ることの知見を得、本発明を完成したものである。
【０００７】
すなわち、本発明は、
１．二酸化チタン粒子表面に、高密度シリカの第一被覆層と多孔質シリカの第二被覆層とを有する二酸化チタン顔料、
２．高密度シリカの第一被覆層を有する二酸化チタン顔料の水性スラリーのｐＨを１〜４に保持しながら、ケイ酸塩溶液と酸もしくはアルカリを添加して、多孔質シリカを被覆することを特徴とする二酸化チタン顔料の製造方法、
３．二酸化チタン顔料の水性スラリーを８０℃以上でｐＨ９以上に調整し、次いでケイ酸塩を添加し、しかる後酸で緩徐に中和し、この高密度シリカの第一被覆層を有する二酸化チタン顔料の水性スラリーのｐＨを１〜４に保持しながら、ケイ酸塩溶液と酸もしくはアルカリを添加して、多孔質シリカを被覆することを特徴とする二酸化チタン顔料の製造方法、
４．多孔質シリカの第二被覆層処理後ポリオール化合物を被覆処理することを特徴とする二酸化チタン顔料の製造方法、
５．前記の二酸化チタン顔料を水性媒体に分散させてなる水性分散体及び、
６．前記の水性分散体に、エマルション樹脂を配合してなる水性塗料である。
【０００８】
本発明に用いる二酸化チタンは、例えば硫酸チタン溶液を加水分解し、得られた含水酸化チタンを焼成するいわゆる硫酸法や、ハロゲン化チタンを気相酸化するいわゆる塩素法で製造されたものを用いることができ、その平均粒子径は０．１〜１．０μｍ程度のものであって、その結晶形はアナタース型，ルチル型のいずれでもよく、さらにアナタース型二酸化チタンとルチル型二酸化チタンとを混合した混合物でもよい。なお、前記硫酸法の二酸化チタンにあっては、その製造工程の焼成過程で例えば亜鉛、カリウム、アルミニウム、リチウム、ニオブ、マグネシウムなどの金属またはリンなどの化合物を焼成処理剤として添加することもでき、また塩素法二酸化チタンにあっては、その製造工程における四塩化チタンの酸化過程で例えばアルミニウム、カリウムなどの化合物を処理剤として添加してもよい。
【０００９】
本発明において、二酸化チタン粒子表面に、高密度シリカの第一被覆層と多孔質シリカの第二被覆層とを形成するには、まず、二酸化チタンの水性スラリーを調製する。スラリーの濃度は、普通１００〜６００ｇ／ｌ、好ましくは２００〜４００ｇ／ｌである。
【００１０】
このスラリーはアルカリ化合物たとえば水酸化ナトリウム、水酸化カリウム、アンモニアなどによりpHを９以上に調整するのがよい。また、このスラリーに必要に応じ適当な分散剤たとえばリン酸塩、ケイ酸塩、ポリアクリル酸塩などを添加して二酸化チタンの分散を良くすることができる。リン酸塩としてヘキサメタリン酸ナトリウム、ピロリン酸ナトリウムなどを使用するときは、普通二酸化チタンに対し０．０１〜３％（Ｐ換算重量％）が好ましい添加量である。
【００１１】
次に、二酸化チタンの水性スラリーに対してケイ酸塩を添加し、ついで加温するか、もしくは加温下にケイ酸塩を添加する。ケイ酸塩としては、ケイ酸ナトリウム、ケイ酸カリウムなどの種々のケイ酸塩およびその他のケイ素化合物を使用することができる。とくに水ガラスが好ましいものの一つである。二酸化チタン粒子表面に被覆する高密度シリカの被覆量は、二酸化チタンの重量に対してSiO2として１〜１０重量％、望ましくは２〜６重量％であり、前記範囲より少な過ぎると耐候性等の所望の効果が得られず、また、多過ぎると経済的に有利でないばかりか分散性、塗膜光沢が損なわれたりする。
【００１２】
ケイ酸塩は、予めその添加前に必要に応じて所定濃度になるように水または弱アルカリ水溶液で希釈し、所定量を添加する。ついで添加終了後さらに充分に撹拌し混合する。続いてスラリーの温度を８０℃以上、望ましくは９０℃以上に維持するように攪拌しながら酸で緩徐に中和する。なお、前記スラリーの加温は、ケイ酸塩の添加前、または添加途中であってもよい。ここで使用する酸としては、硫酸、塩酸、硝酸、リン酸、酢酸などが挙げられ、これらによりスラリーのpHを７．５望ましくは７以下に調整する。また中和は緩徐に行い、中和時の温度、スラリー量などによって異なるが、通常望ましくは３０分間以上さらに望ましくは１時間以上かけて行うのがよい。なお必要に応じ、さらに撹拌下に前記温度を保持しながら熟成処理する。中和および熟成の間も前記の温度に維持するのがよく、熟成温度を更に高くすることにより一層好ましい効果をもたらす場合がある。上記の中和時の望ましい温度、望ましい中和時間などは、シリカをとくに高密度に被覆させるのに好適である。中和時の温度が低きに過ぎたり、中和時間が短きに過ぎたりすると、高密度シリカの被覆層を形成させるのが困難となる。
【００１３】
次に、二酸化チタン粒子表面に高密度シリカの第一被覆層を有する上記被覆二酸化チタンに、多孔質シリカの第二被覆層を形成するには、まず、被覆二酸化チタンの水性スラリーを調製する。このスラリーの濃度は、普通１００〜６００ｇ／ｌ、好ましくは２００〜４００ｇ／ｌである。
【００１４】
このスラリーは、酸たとえば硫酸、塩酸、硝酸、リン酸、酢酸などによりpHを１〜４、望ましくはpH２〜３に調整する。また、このスラリーに必要に応じ適当な分散剤たとえばリン酸塩、ケイ酸塩、ポリアクリル酸塩などを添加して被覆二酸化チタンの分散を良くすることができる。リン酸塩としてヘキサメタリン酸ナトリウム、ピロリン酸ナトリウムなどを使用するときは、普通二酸化チタンに対し０．０１〜３％（Ｐ換算重量％）が好ましい添加量である。
【００１５】
次に、二酸化チタンの水性スラリーに対してpHを１〜４、望ましくは２〜３に保持しながら酸およびケイ酸塩を添加し、次いで酸又はアルカリで中和して多孔質シリカの第二被覆層を形成する。ケイ酸塩としては、ケイ酸ナトリウム、ケイ酸カリウムなどの種々のケイ酸塩およびその他のケイ素化合物を使用することができる。とくに水ガラスが好ましいものの一つである。二酸化チタン粒子表面に被覆する多孔質シリカの被覆量は、二酸化チタンの重量に対してSiO2として１〜１０重量％、望ましくは２〜５重量％であり、前記範囲より少な過ぎると生産性の低下を来たす等の所望の効果が得られず、また、多過ぎると経済的に有利でないばかりか塗膜光沢が損なわれ易かったりする。
【００１６】
ケイ酸塩は、予めその添加前に必要に応じて所定濃度になるように水または弱アルカリ水溶液で希釈し、所定量を添加する。中和時の被覆二酸化チタン分散液の温度は適宜設定できるが、通常室温から９０℃程度が適当である。
【００１７】
本発明においては、次に前記被覆処理スラリーを濾過、洗浄、乾燥し、粉砕処理して、表面被覆処理された二酸化チタン顔料として回収する。具体的には、中和反応後のスラリーは、一定時間、普通１０〜６０分間、４０〜９０℃の温度で熟成後公知の方法に従って分別し、洗浄し、乾燥し、必要に応じて乾式粉砕などの工程を経て二酸化チタン顔料製品とする。この乾燥後の乾式粉砕は通常、ジェットミルやマイクロナイザーなどの気流粉砕機、ローラーミル、パルペライザーなどで行う。
【００１８】
なお、前記のようにして得られた二酸化チタン顔料は、必要に応じ種々の有機物を表面処理することもできる。前記有機物としては、種々のものを使用し得るが、例えばポリオール系又はアミン系のものがあり、具体例としては例えばトリメチロールメタン、トリメチロールエタン、ペンタエリスリノール、ジメチルエタノールアミン、トリエタノールアミンなどが挙げられる。これらの添加量は、水性塗料系での例えば耐水性などの塗膜性能を損なわない範囲でなるベく少量であるのが望ましい。また、前記のようにして得られた二酸化チタン顔料を、水性媒体に分散させてなる高濃度の顔料水性分散体を調製し塗料化に供するには、場合によっては前記表面被覆処理後の濾過、洗浄ケーキを水性媒体に分散させりことによっても調製することができる。前記水性分散体の固形分濃度は４０〜８０重量％、望ましくは６０〜８０重量％で、pHは、６〜９である。
【００１９】
本発明の二酸化チタン顔料は、色材として塗料やプラスチックス、インキのほか種々の分野に適用し得るものであるが、とりわけ水性系塗料、特にエマルション系塗料の塗料化に好適なものであり、前記エマルション系塗料ビヒクルとしては、種々のいわゆる合成樹脂エマルション系のものや、合成ラテックス系のものなど広範なものを使用し得る。前記水性エマルション塗料の酸化チタン顔料濃度は１５〜６０重量％、樹脂と酸化チタン顔料の固形分重量比は２／１〜１／１０、pHは、６〜１０である。
【００２０】
【実施例】
実施例１
四塩化チタンを気相で酸化して得られた二酸化チタンを粉砕し、分級してＴｉＯ2 濃度３００ｇ／ｌの水性スラリーとし、水酸化ナトリウム水溶液を添加して、スラリーpHを１０．５とした後、３０分間超音波分散を行った。次いで該スラリー４０００ｍｌを撹拌下に、７５℃に昇温し該温度を保持しながら水ガラス(JIS 3号）水溶液（Siとして７重量％含有）を３２０ｍｌ添加し、その後３０分間撹拌し混合した。次いで９０℃に昇温した後１Ｎの硫酸水溶液を約３ｍｌ／分の速度で４０分間添加して、pHが５となるまで中和した。その後さらに７０℃に保持し、撹拌下に６０分間熟成した。
次に、上記で得た被覆二酸化チタンスラリーに硫酸を添加してpHを２に調整した。次いで撹拌下に、水性スラリーのpHを２に保持しながら、水ガラス(JIS 3号）水溶液（Siとして７重量％含有）１６０ｍｌを、硫酸と共に添加した。次いで２Ｎの硫酸水溶液を約１ｍｌ／分の速度で６０分間添加して、pHが８となるまで中和した。その後さらに７０℃でpH７に保持し、撹拌下に６０分間熟成した。
この生成スラリーを濾過、水洗、乾燥、粉砕して高密度シリカの第一被覆層と多孔質シリカの第二被覆層とを有する本発明の二酸化チタン顔料（試料Ａ）を得た。
【００２１】
実施例２
前記実施例１で得られた二酸化チタン顔料（試料Ａ）１００重量部に対してトリメチロールエタン０．５重量部添加処理して本発明の二酸化チタン顔料（試料Ｂ）を得た。
【００２２】
比較例１
実施例１において、高密度シリカ及び多孔質シリカの被覆処理を行うことなく、アルミナ被覆処理（Al2O3 として２重量％）のみを行ったことの他は、同例の場合と同様に処理して比較例の二酸化チタン顔料（試料Ｃ）を得た。
【００２３】
比較例２
実施例１において、多孔質シリカの被覆処理を行うことなく、アルミナ被覆処理（Al2O3 として２重量％）を行ったことの他は、同例の場合と同様に処理して比較例の二酸化チタン顔料（試料Ｄ）を得た。
【００２４】
前記実施例及び比較例で得られた各試料の二酸化チタン顔料について、次の試験を実施した。
【００２５】
試験１
脱イオン水９０ｇに対し、所定の濃度になるように酸化チタン顔料を加え、ディスパー（ＴＫディスパー、東京機工製）で１０分間分散させた。その後分散スラリーの粘度をコーンプレート型粘度計（Ｅ型粘度計、TOKIMEC 社製、２０℃、シェアレート１９２〜２００ s-1）でスラリー粘度を測定した。結果を表１に示す。
【００２６】
【表１】
表１より明らかなように本発明の二酸化チタン顔料は、比較例のものに比べ水分散性に優れ、高濃度の水分散体が得られることがわかる。
【００２８】
試験２
下記の配合組成で二酸化チタン顔料水性分散体を調製した。
顔料水性分散体 重量（ｇ）
二酸化チタン ８５
水 ３０
メチルカルビトール ６．４
タモール731 分散剤（固形分２５％） １．７
トライトンＣＦ−１０界面活性剤 １．０
フォマスターＶＬ 消泡剤 ０．４
ガラスビーズ ８０．０
タモール731 は、ポリカルボキシレート系分散剤（タモールはロームアンドハース社の登録商標である）である。トライトンＣＦ−１０は、アルキルアリルポリエーテル界面活性剤（トライトンはロームアンドハース社の登録商標である）である。フォマスターＶＬは消泡剤（フォマスターはサンノプコ社の登録商標である）である。これらの成分をペイントコンディショナー（レッドデビル社製）で２０分間分散させ、以下の配合組成でゆっくりとレットダウンして塗料化した。
【００２９】
配合組成 重量（ｇ）
二酸化チタン顔料水性分散体 ４９．２
水 ３２．１
ブチルカルビトール １２．０
プライマルQR-708 レオロジー改質剤 １．６
テキサノール 造膜助剤 ６．９
アンモニア水（２８％） ０．７
メインコートHG-54 １１０．１
プライマルとメインコートは、ロームアンドハース社の登録商標であり、テキサノールは、イーストマンコダック社の登録商標である。
【００３０】
前記の方法によって調製した塗料を、ガラス板にチミルアプリケーターで塗布し、１週間常温で乾燥させた後、２０°−２０°及び６０°−６０°光沢を測定した。この結果を表２に示す。
【００３１】
次に前記で調製した塗料を、白黒チャート紙＃３０バーコーターで塗布し、常温で１週間乾燥させた。その後黒地上の反射率（ＹＢ値）と白地上の反射率（ＹＷ値）を計測し、それらからコントラストレシオ（ＣＲ値）を下記式により求めた。その結果を表２に示した。
【００３２】
【数１】
さらに、前記で調製した塗料を、リン酸亜鉛処理鋼板（３．５cm×１５cm）上に約７０μｍ厚（乾燥塗膜として）に塗布し、常温で１週間乾燥して試験板を作製した。この試験板について、カーボンアーク型サンシャインウエザーメーター装置内で促進曝露（６０分照射中に１２分降水、ブラックパネル温度６３±３℃）した。白亜化進行度合を日本塗料検査協会の塗膜評価基準に準じて評価するとともに、光沢保持性を一定間隔ごとに測定し、それらを総合評価して耐候性評価とした（○印：良好、×：不良）。この結果を表２に示す。
【００３４】
【表２】
表２から明らかなように、本発明の二酸化チタン顔料は比較例のものに比べ光沢が同等以上であり、分散性にも優れていることがわかる。また、本発明の二酸化チタン顔料は比較例のものに比べＹＢ値、ＣＲ値とも大きく隠蔽性に優れていることがわかる。
【００３６】
【発明の効果】
本発明の二酸化チタン顔料は、その粒子表面に、高密度シリカの第一被覆層と多孔質シリカの第二被覆層とを有するものであって、とりわけ水性塗料、特にエマルション系塗料に特に好適なものである。このものは、分散作業性に優れているほか、塗膜の隠蔽力、光沢、耐候性、さらには被覆処理時の生産効率にも優れたものである。このものは、建築用塗料や汎用の工業用塗料などに好適なものであるほか、プラスチック、インキなどに使用され得る甚だ有用なものである。[0001]
[Industrial application fields]
The present invention relates to a titanium dioxide pigment for an aqueous dispersion and a method for producing the same.
[0002]
TECHNICAL BACKGROUND OF THE INVENTION
In the paint field, the direction toward water-based solvent-based paints has been further strengthened in conjunction with the safety of the global environment, the safety of the work environment, hygiene, and resource saving.
[0003]
By the way, water-based solvent-based paints, especially emulsion paints, are usually dry and have many features such as excellent odor and fire safety and good paint workability. Today, they are used in large quantities in various application fields as industrial and household paints.
[0004]
Emulsion paints are basically made by mixing and dispersing pigments in the synthetic resin emulsion of the vehicle, which is the main component, but the emulsion system is destroyed when subjected to a strong mechanical impact during this dispersion process. In many cases, it is difficult to disperse under strong shearing force as in solvent-type vehicle paints. For this reason, a high-concentration pigment slurry is usually prepared by suspending and dispersing titanium dioxide pigment and extender pigment in an aqueous medium in the presence of various dispersants and thickeners. It has been practiced to add a paint to an emulsion.
[0005]
[Problems to be solved by the invention]
However, the dispersant is useful for improving the dispersibility, but it is useful for imparting dispersibility of the titanium dioxide pigment, while impairing the physical properties of the coating such as water resistance of the coating. Even in such a case, there are not a few problems that need improvement, such as easy dispersibility of extender pigments. For this reason, there is a strong demand for easily dispersible pigments, in particular titanium dioxide pigments, which are the main constituents, in the absence of a dispersant or in which the addition amount can be minimized.
[0006]
[Means for Solving the Problems]
The inventors of the present invention have previously studied in detail about the above-mentioned problem in order to solve the problem by modifying the particle surface of the titanium dioxide pigment with a metal hydrated oxide or oxide. Surprisingly, (1) High pigment concentration with excellent dispersion workability in emulsion paint system by having only silica coating layers with different precipitate forms on the particle surface of titanium dioxide pigment in a specific order. (2) The emulsion paint formed by using the aqueous dispersion of titanium dioxide pigment having a high pigment concentration described in (1) has excellent hiding performance and water resistance. In addition to providing coating performance such as performance, it is possible to provide coating performance with excellent gloss in a so-called gloss emulsion system, and (3) Obtained a finding that the coating process tends processing slurry or cake was raised in steps difficulties in handling due to thixotropic viscosity and production efficiency decreases and the be substantially avoided, and completed the present invention.
[0007]
That is, the present invention
1. A titanium dioxide pigment having a first coating layer of high-density silica and a second coating layer of porous silica on the surface of the titanium dioxide particles;
2. The porous silica is coated by adding a silicate solution and an acid or alkali while maintaining the pH of the aqueous slurry of titanium dioxide pigment having the first coating layer of high-density silica at 1 to 4. A method for producing a titanium dioxide pigment,
3. An aqueous slurry of titanium dioxide pigment is adjusted to a pH of 9 or more at 80 ° C. or higher, silicate is added, and then neutralized slowly with an acid. A method for producing a titanium dioxide pigment, characterized by adding a silicate solution and an acid or an alkali while coating the porous silica while maintaining the pH of the aqueous slurry at 1 to 4.
4). A method for producing a titanium dioxide pigment, wherein the polyol compound is coated after the second coating layer treatment of the porous silica;
5. An aqueous dispersion obtained by dispersing the titanium dioxide pigment in an aqueous medium; and
6). It is an aqueous paint obtained by blending an emulsion resin with the aqueous dispersion.
[0008]
The titanium dioxide used in the present invention is, for example, one produced by hydrolyzing a titanium sulfate solution and calcining the resulting hydrous titanium oxide, or by a so-called chlorine method for vapor-phase oxidation of titanium halide. The average particle diameter is about 0.1 to 1.0 μm, the crystal form may be either anatase type or rutile type, and anatase type titanium dioxide and rutile type titanium dioxide are mixed. It may be a mixture. In addition, in the sulfuric acid method titanium dioxide, for example, a metal such as zinc, potassium, aluminum, lithium, niobium, magnesium or a compound such as phosphorus can be added as a baking treatment agent in the baking process of the manufacturing process. In the case of chlorinated titanium dioxide, for example, a compound such as aluminum or potassium may be added as a treating agent during the oxidation process of titanium tetrachloride in the production process.
[0009]
In the present invention, an aqueous slurry of titanium dioxide is first prepared in order to form a first coating layer of high-density silica and a second coating layer of porous silica on the surface of titanium dioxide particles. The concentration of the slurry is usually 100 to 600 g / l, preferably 200 to 400 g / l.
[0010]
This slurry is preferably adjusted to a pH of 9 or more with an alkali compound such as sodium hydroxide, potassium hydroxide, or ammonia. Further, if necessary, an appropriate dispersing agent such as phosphate, silicate, polyacrylate or the like can be added to the slurry to improve the dispersion of titanium dioxide. When sodium hexametaphosphate, sodium pyrophosphate or the like is used as a phosphate, 0.01 to 3% (weight% in terms of P) is a preferable addition amount with respect to ordinary titanium dioxide.
[0011]
Next, silicate is added to the aqueous slurry of titanium dioxide and then heated, or silicate is added under heating. As the silicate, various silicates such as sodium silicate and potassium silicate and other silicon compounds can be used. Water glass is particularly preferred. The coating amount of the high-density silica coated on the surface of the titanium dioxide particles is 1 to 10% by weight, preferably 2 to 6% by weight as SiO 2 with respect to the weight of titanium dioxide, and if it is less than the above range, the weather resistance, etc. In addition, if the amount is too large, it is not economically advantageous, and the dispersibility and gloss of the coating film are impaired.
[0012]
The silicate is diluted in advance with water or a weak alkaline aqueous solution so as to have a predetermined concentration before the addition, and a predetermined amount is added. Then, after the addition is completed, the mixture is further stirred and mixed. Subsequently, the slurry is neutralized slowly with acid while stirring so as to maintain the temperature of the slurry at 80 ° C. or higher, desirably 90 ° C. or higher. The slurry may be heated before or during the addition of the silicate. Examples of the acid used here include sulfuric acid, hydrochloric acid, nitric acid, phosphoric acid, acetic acid, and the like, and the pH of the slurry is adjusted to 7.5, desirably 7 or less. Neutralization is performed slowly and varies depending on the temperature at the time of neutralization, the amount of slurry, etc., but it is usually preferably 30 minutes or longer, more preferably 1 hour or longer. If necessary, aging treatment is performed while maintaining the temperature while stirring. It is preferable to maintain the above temperature during neutralization and ripening, and there is a case where a more favorable effect is brought about by further raising the ripening temperature. The above desirable temperature during neutralization, desirable neutralization time, etc. are suitable for coating silica in a particularly high density. If the temperature during neutralization is too low or the neutralization time is too short, it becomes difficult to form a coating layer of high-density silica.
[0013]
Next, in order to form the second coating layer of porous silica on the above-mentioned coated titanium dioxide having the first coating layer of high-density silica on the surface of the titanium dioxide particles, first, an aqueous slurry of coated titanium dioxide is prepared. The concentration of this slurry is usually 100 to 600 g / l, preferably 200 to 400 g / l.
[0014]
The slurry is adjusted to pH 1 to 4, preferably pH 2 to 3, with an acid such as sulfuric acid, hydrochloric acid, nitric acid, phosphoric acid, acetic acid or the like. Further, if necessary, an appropriate dispersing agent such as phosphate, silicate, polyacrylate or the like can be added to the slurry to improve the dispersion of the coated titanium dioxide. When sodium hexametaphosphate, sodium pyrophosphate or the like is used as a phosphate, 0.01 to 3% (weight% in terms of P) is a preferable addition amount with respect to ordinary titanium dioxide.
[0015]
Next, acid and silicate are added to the aqueous slurry of titanium dioxide while maintaining the pH at 1 to 4, preferably 2 to 3, and then neutralized with acid or alkali to obtain a second porous silica. A coating layer is formed. As the silicate, various silicates such as sodium silicate and potassium silicate and other silicon compounds can be used. Water glass is particularly preferred. The amount of porous silica coated on the surface of titanium dioxide particles is 1 to 10% by weight, preferably 2 to 5% by weight as SiO 2 with respect to the weight of titanium dioxide. A desired effect such as a reduction cannot be obtained, and too much is not economically advantageous, and the gloss of the coating film is easily impaired.
[0016]
The silicate is diluted in advance with water or a weak alkaline aqueous solution so as to have a predetermined concentration before the addition, and a predetermined amount is added. The temperature of the coated titanium dioxide dispersion at the time of neutralization can be set as appropriate, but usually from room temperature to about 90 ° C. is appropriate.
[0017]
In the present invention, the coating treatment slurry is then filtered, washed, dried, pulverized, and recovered as a surface-coated titanium dioxide pigment. Specifically, the slurry after the neutralization reaction is aged at a temperature of 40 to 90 ° C. for a certain period of time, usually 10 to 60 minutes, and then separated according to a known method, washed, dried, and dry pulverized as necessary. The titanium dioxide pigment product is made through these processes. This dry pulverization after drying is usually carried out with an airflow pulverizer such as a jet mill or a micronizer, a roller mill, a pulverizer, or the like.
[0018]
The titanium dioxide pigment obtained as described above can be surface-treated with various organic substances as required. Various organic substances can be used as the organic substance, for example, there are polyol type or amine type. Specific examples include trimethylolmethane, trimethylolethane, pentaerythrinol, dimethylethanolamine, triethanolamine and the like. Is mentioned. The addition amount of these is desirably a small amount within a range not impairing the coating performance such as water resistance in the aqueous coating system. In addition, in order to prepare a high-concentration pigment aqueous dispersion obtained by dispersing the titanium dioxide pigment obtained as described above in an aqueous medium and use it for coating, in some cases, filtration after the surface coating treatment, It can also be prepared by dispersing the wash cake in an aqueous medium. The aqueous dispersion has a solid concentration of 40 to 80% by weight, preferably 60 to 80% by weight, and a pH of 6 to 9.
[0019]
The titanium dioxide pigment of the present invention can be applied to various fields in addition to paints, plastics and inks as a color material, and is particularly suitable for making water-based paints, particularly emulsion paints, As the emulsion-based paint vehicle, various types such as various so-called synthetic resin emulsion-based ones and synthetic latex-based ones can be used. The aqueous emulsion paint has a titanium oxide pigment concentration of 15 to 60% by weight, a solid content weight ratio of the resin and the titanium oxide pigment of 2/1 to 1/10, and a pH of 6 to 10.
[0020]
【Example】
Example 1
Titanium dioxide obtained by oxidizing titanium tetrachloride in the gas phase is pulverized and classified into an aqueous slurry having a TiO 2 concentration of 300 g / l, and an aqueous sodium hydroxide solution is added to make the slurry pH 10.5. Thereafter, ultrasonic dispersion was performed for 30 minutes. Next, 4000 ml of the slurry was heated to 75 ° C. with stirring, and 320 ml of water glass (JIS 3) aqueous solution (containing 7 wt% as Si) was added while maintaining the temperature, and then stirred and mixed for 30 minutes. Next, the temperature was raised to 90 ° C., and then a 1N sulfuric acid aqueous solution was added at a rate of about 3 ml / min for 40 minutes to neutralize the pH to 5. Thereafter, the mixture was further maintained at 70 ° C. and aged for 60 minutes with stirring.
Next, sulfuric acid was added to the coated titanium dioxide slurry obtained above to adjust the pH to 2. Next, 160 ml of water glass (JIS No. 3) aqueous solution (containing 7% by weight of Si) was added together with sulfuric acid while maintaining the pH of the aqueous slurry at 2 with stirring. Next, a 2N aqueous sulfuric acid solution was added at a rate of about 1 ml / min for 60 minutes to neutralize the pH to 8. Thereafter, the pH was further maintained at 70 ° C. and aged for 60 minutes with stirring.
The resulting slurry was filtered, washed with water, dried and pulverized to obtain a titanium dioxide pigment of the present invention (sample A) having a first coating layer of high-density silica and a second coating layer of porous silica.
[0021]
Example 2
The titanium dioxide pigment (sample B) of the present invention was obtained by adding 0.5 parts by weight of trimethylolethane to 100 parts by weight of the titanium dioxide pigment (sample A) obtained in Example 1.
[0022]
Comparative Example 1
In Example 1, the same treatment as in Example 1 was performed except that only the alumina coating treatment (2% by weight as Al 2 O 3 ) was performed without coating the high-density silica and the porous silica. Thus, a titanium dioxide pigment (sample C) of a comparative example was obtained.
[0023]
Comparative Example 2
In Example 1, the same process as in Example 1 was performed except that the alumina coating process (2% by weight as Al 2 O 3 ) was performed without performing the coating process of porous silica. A titanium dioxide pigment (sample D) was obtained.
[0024]
The following tests were carried out on the titanium dioxide pigments of the samples obtained in the examples and comparative examples.
[0025]
Test 1
A titanium oxide pigment was added to 90 g of deionized water so as to have a predetermined concentration, and dispersed with a disper (TK Disper, manufactured by Tokyo Kiko) for 10 minutes. Thereafter, the viscosity of the dispersed slurry was measured with a cone plate viscometer (E type viscometer, manufactured by TOKIMEC, 20 ° C., shear rate 192 to 200 s −1 ). The results are shown in Table 1.
[0026]
[Table 1]
As can be seen from Table 1, the titanium dioxide pigment of the present invention is superior in water dispersibility compared to the comparative example, and a high concentration aqueous dispersion can be obtained.
[0028]
Test 2
An aqueous titanium dioxide pigment dispersion was prepared with the following composition.
Pigment aqueous dispersion Weight (g)
Titanium dioxide 85
Water 30
Methyl carbitol 6.4
Tamol 731 Dispersant (25% solids) 1.7
Triton CF-10 surfactant 1.0
Formaster VL Antifoam 0.4
Glass beads 80.0
Tamol 731 is a polycarboxylate dispersant (Tamol is a registered trademark of Rohm and Haas). Triton CF-10 is an alkyl allyl polyether surfactant (Triton is a registered trademark of Rohm and Haas). Phomaster VL is an antifoaming agent (Phomaster is a registered trademark of San Nopco). These components were dispersed with a paint conditioner (manufactured by Red Devil) for 20 minutes and slowly let down with the following composition to make a paint.
[0029]
Formulation composition Weight (g)
Titanium dioxide pigment aqueous dispersion 49.2
Water 32.1
Butyl carbitol 12.0
Primal QR-708 Rheology modifier 1.6
Texanol film-forming aid 6.9
Ammonia water (28%) 0.7
Main coat HG-54 110.1
Primal and Main Coat are registered trademarks of Rohm and Haas, and Texanol is a registered trademark of Eastman Kodak Company.
[0030]
The paint prepared by the above method was applied to a glass plate with a thymil applicator and dried at room temperature for 1 week, and then the 20 ° -20 ° and 60 ° -60 ° gloss was measured. The results are shown in Table 2.
[0031]
Next, the paint prepared as described above was applied with black and white chart paper # 30 bar coater and dried at room temperature for 1 week. Thereafter, the reflectance on the black ground (YB value) and the reflectance on the white ground (YW value) were measured, and the contrast ratio (CR value) was determined from them by the following equation. The results are shown in Table 2.
[0032]
[Expression 1]
Furthermore, the coating material prepared above was applied on a zinc phosphate-treated steel plate (3.5 cm × 15 cm) to a thickness of about 70 μm (as a dry coating film) and dried at room temperature for 1 week to prepare a test plate. This test plate was subjected to accelerated exposure in a carbon arc type sunshine weather meter device (12 minutes precipitation during 60 minutes irradiation, black panel temperature 63 ± 3 ° C.). In addition to evaluating the degree of chalking according to the paint evaluation standards of the Japan Paint Inspection Association, gloss retention was measured at regular intervals, and these were comprehensively evaluated for weather resistance evaluation (marked with ○: good, × : Defect). The results are shown in Table 2.
[0034]
[Table 2]
As is apparent from Table 2, the titanium dioxide pigment of the present invention has a gloss equivalent to or higher than that of the comparative example and is excellent in dispersibility. Further, it can be seen that the titanium dioxide pigment of the present invention has a large YB value and CR value and is excellent in concealing property as compared with the comparative example.
[0036]
【The invention's effect】
The titanium dioxide pigment of the present invention has a first coating layer of high-density silica and a second coating layer of porous silica on the particle surface, and is particularly suitable for aqueous paints, particularly emulsion paints. Is. In addition to excellent dispersibility, this material is excellent in coating film hiding power, gloss, weather resistance, and production efficiency during coating treatment. This is not only suitable for architectural paints and general-purpose industrial paints, but is also very useful that can be used for plastics, inks and the like.
Claims (3)
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP30366696A JP3773220B2 (en) | 1996-10-28 | 1996-10-28 | Titanium dioxide pigment and method for producing the same |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP30366696A JP3773220B2 (en) | 1996-10-28 | 1996-10-28 | Titanium dioxide pigment and method for producing the same |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPH10130527A JPH10130527A (en) | 1998-05-19 |
| JP3773220B2 true JP3773220B2 (en) | 2006-05-10 |
Family
ID=17923771
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP30366696A Expired - Lifetime JP3773220B2 (en) | 1996-10-28 | 1996-10-28 | Titanium dioxide pigment and method for producing the same |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JP3773220B2 (en) |
Families Citing this family (18)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP4688286B2 (en) * | 1999-12-17 | 2011-05-25 | 石原産業株式会社 | Titanium dioxide pigment and method for producing the same |
| US6616746B2 (en) | 1999-12-17 | 2003-09-09 | Ishihara Sangyo Kaisha, Ltd. | Titanium dioxide pigment and method for production thereof |
| JP4668583B2 (en) * | 2004-11-04 | 2011-04-13 | 石原産業株式会社 | Titanium dioxide pigment |
| JP4982953B2 (en) * | 2005-02-14 | 2012-07-25 | 日産自動車株式会社 | Resin composition, method for producing resin composition, automotive member, building member, and optical component |
| US7863215B2 (en) | 2005-02-15 | 2011-01-04 | Mitsui Chemicals, Inc. | Photocatalyst, method for producing same, liquid dispersion containing photocatalyst and photocatalyst coating composition |
| JP4836232B2 (en) * | 2005-07-07 | 2011-12-14 | テイカ株式会社 | Method for producing silica-coated fine particle titanium oxide or silica-coated fine particle zinc oxide |
| WO2007039984A1 (en) * | 2005-09-30 | 2007-04-12 | Mitsui Chemicals, Inc. | Photocatalyst-containing organic material |
| JP4906361B2 (en) * | 2006-01-27 | 2012-03-28 | 三井化学株式会社 | Inorganic oxide ultrafine particles and production method thereof |
| JP5609873B2 (en) | 2009-07-27 | 2014-10-22 | 旭硝子株式会社 | Composite particles, coating film forming compositions, printing inks, coating compositions, coated articles, and resin films with coating films |
| KR20120052244A (en) | 2009-07-29 | 2012-05-23 | 아사히 가라스 가부시키가이샤 | Fluororesin film and method for producing same |
| JP6061097B2 (en) | 2011-08-08 | 2017-01-18 | セイコーエプソン株式会社 | Aqueous ink pigment, aqueous ink composition containing the same, and image or printed matter thereof |
| US20150329723A1 (en) | 2012-12-28 | 2015-11-19 | Seiko Epson Corporation | Surface coated particles and use of same |
| US9353266B2 (en) | 2013-03-15 | 2016-05-31 | Tronox Llc | Process for manufacturing titanium dioxide pigments using ultrasonication |
| EP3190159A1 (en) * | 2016-01-08 | 2017-07-12 | Kronos International, Inc. | Method for forming a finish surface on a substrate |
| KR20200084870A (en) * | 2017-10-17 | 2020-07-13 | 베나토 피앤에이 핀란드 오와이 | Method for manufacturing coated titanium dioxide particles, coated titanium dioxide particles and products comprising same |
| CN114014355B (en) * | 2021-09-16 | 2023-07-25 | 攀枝花学院 | Industrial meta-titanic acid purifying and deironing method |
| CN115090076B (en) * | 2022-07-05 | 2023-07-21 | 王西峰 | Quartz glass fiber loaded titanium dioxide photocatalyst filler and preparation method and application thereof |
| CN117186690A (en) * | 2023-09-06 | 2023-12-08 | 山东英诺新材料有限公司 | Preparation method of water-based ink for flexible package |
-
1996
- 1996-10-28 JP JP30366696A patent/JP3773220B2/en not_active Expired - Lifetime
Also Published As
| Publication number | Publication date |
|---|---|
| JPH10130527A (en) | 1998-05-19 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| JP3696993B2 (en) | Method for producing titanium dioxide pigment | |
| JP3773220B2 (en) | Titanium dioxide pigment and method for producing the same | |
| JP5209861B2 (en) | Titanium dioxide white pigment and method for producing the same | |
| US5165995A (en) | Process for coating titanium dioxide pigments | |
| USRE27818E (en) | Titanium dioxide pigment coated with silica and alumina | |
| CN101675119B (en) | Making co-precipitated mixed oxide-treated titanium dioxide pigments | |
| US4505755A (en) | Method of producing surface-treated barium sulfate | |
| US20020017221A1 (en) | Continuous processes for producing titanium dioxide pigments | |
| JP4668705B2 (en) | Method for producing titanium dioxide pigment | |
| JP2001527597A (en) | Method for producing a lightfast titanium dioxide pigment aqueous slurry | |
| US9539557B2 (en) | Treated inorganic pigments having improved dispersability and use thereof in coating compositions | |
| US9573108B2 (en) | Treated inorganic core particles having improved dispersability | |
| EP2864424B1 (en) | Manufacture of titanium dioxide pigments using ultrasonication | |
| JPS5930749B2 (en) | Titanium dioxide pigment composition and its manufacturing method | |
| JP2002510351A (en) | Method for producing light-fast aqueous titanium dioxide pigment slurry | |
| JPH09221604A (en) | Composite material for pigment | |
| US5338354A (en) | Composite pigmentary material | |
| DE10134272C1 (en) | Use of titanium dioxide coated with magnesium phosphate and aluminum oxide and/or hydroxide as an anticorrosion white pigment, e.g. in coatings | |
| JPH07751B2 (en) | Fine particle titanium dioxide powder | |
| JP4668583B2 (en) | Titanium dioxide pigment | |
| JPH0769636A (en) | Iron-containing titanium dioxide and production thereof | |
| JPH0252660B2 (en) | ||
| JPH0348136B2 (en) | ||
| JPS6224019B2 (en) | ||
| JPH0649387A (en) | Titanium dioxide pigment and its production |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| A977 | Report on retrieval |
Free format text: JAPANESE INTERMEDIATE CODE: A971007 Effective date: 20050930 |
|
| A131 | Notification of reasons for refusal |
Free format text: JAPANESE INTERMEDIATE CODE: A131 Effective date: 20051025 |
|
| A521 | Written amendment |
Free format text: JAPANESE INTERMEDIATE CODE: A523 Effective date: 20051222 |
|
| TRDD | Decision of grant or rejection written | ||
| A01 | Written decision to grant a patent or to grant a registration (utility model) |
Free format text: JAPANESE INTERMEDIATE CODE: A01 Effective date: 20060207 |
|
| A61 | First payment of annual fees (during grant procedure) |
Free format text: JAPANESE INTERMEDIATE CODE: A61 Effective date: 20060213 |
|
| FPAY | Renewal fee payment (event date is renewal date of database) |
Free format text: PAYMENT UNTIL: 20090224 Year of fee payment: 3 |
|
| FPAY | Renewal fee payment (event date is renewal date of database) |
Free format text: PAYMENT UNTIL: 20100224 Year of fee payment: 4 |
|
| FPAY | Renewal fee payment (event date is renewal date of database) |
Free format text: PAYMENT UNTIL: 20110224 Year of fee payment: 5 |
|
| FPAY | Renewal fee payment (event date is renewal date of database) |
Free format text: PAYMENT UNTIL: 20110224 Year of fee payment: 5 |
|
| FPAY | Renewal fee payment (event date is renewal date of database) |
Free format text: PAYMENT UNTIL: 20120224 Year of fee payment: 6 |
|
| FPAY | Renewal fee payment (event date is renewal date of database) |
Free format text: PAYMENT UNTIL: 20120224 Year of fee payment: 6 |
|
| FPAY | Renewal fee payment (event date is renewal date of database) |
Free format text: PAYMENT UNTIL: 20130224 Year of fee payment: 7 |
|
| FPAY | Renewal fee payment (event date is renewal date of database) |
Free format text: PAYMENT UNTIL: 20140224 Year of fee payment: 8 |
|
| EXPY | Cancellation because of completion of term |