JP4046451B2 - Aqueous dispersion, method for producing the same, and coating composition - Google Patents

Description

【００９１】
表１より合成例１及び２の水性分散体は、ポリマー単独粒子及びコロイド状シリカ粒子が少なく、コア−シェル型複合粒子で構成された水性分散体であった。合成例３の水性分散体は、コア−シェル構造の複合粒子とポリマー単独粒子とで構成されていた。また合成例４の水性分散体は、コア−シェル構造の複合粒子と、コロイド状シリカ粒子とで構成されていた。合成例５の水性分散体は、コア−シェル構造複合粒子／ポリマー単独粒子／コロイド状シリカ粒子の３成分系で構成されていた。これら合成例より、本発明では、前記３成分を任意に合成条件及びノニオン界面活性剤種の調整により調整することができる。
【００９２】
［貯蔵安定性］
合成例１〜２及び１０〜１１、比較合成例１の水性分散体を、常温で３カ月間保存するとともに、温度５０℃で１０日保存して促進貯蔵安定性調べた。結果を表２に示す。
【００９３】
【表２】

【００９４】
合成例１〜２及び１０〜１１の水性分散体は、室温での保存安定性および５０℃での促進試験においても、増粘、外観の変化がなく良好な貯蔵安定性を示した。これに対して、比較合成例では、遊離のシラノール化合物によるためか、憎粘傾向が認められ、特に５０℃での促進試験では著しい増粘が認められた。
【００９５】
［塗料組成物］
実施例１
５００ｍＬのスチール製ビーカーに、蒸留水１０．８ｇ、増粘剤（旭電化工業（株）製，ＵＨ４２０，固形分６重量％）５．０ｇ、分散剤（花王（株）製，デモールＥＰ）４．０ｇ、湿潤剤（花王（株）製，エマルゲンＬ−４０）１．０ｇ、消泡剤（サンノプコ（株）製、ノプコ８０３４）０．８ｇを加え、１０００ｒｐｍで撹拌しながら、二酸化チタン（テイカ（株）製，ＪＲ−６０３）８０ｇを徐々に加え、デイスパーを用い１５分間に亘り回転数３０００ｒｐｍで撹拌を行った。その後、合成例１の水性分散体（エマルジョン）２００ｇを回転数１０００ｒｐｍで徐々に加え、さらに蒸留水６０ｇを加え５分間撹拌を行った。次に、造膜助剤（大阪有機化学工業（株）製、酢酸ブチル ジ ユーキゾール）１２ｇを加え撹拌をさらに５分間続け、白色塗料を得た。
【００９６】
実施例２〜５
表３に示す割合で、上記と同様に塗料組成物を得た。
【００９７】
実施例６
５００ｍＬのスチール製ビーカーに蒸留水１０．８ｇ、消泡剤（サンノプコ（株）製、ノプコ８０３４）０．４ｇを加え、１０００ｒｐｍで攪拌しながら、合成例１０の水性分散体（エマルジョン）２００ｇと、通常のアクリル系エマルジョン（Ｇ−２５、５０重量％、水谷ペイント（株）製）１６０ｇを加えた。続いて、蒸留水６０ｇと増粘剤（旭電化工業（株）製、ＵＨ４２０、固形分６重量％）５．０ｇを加え、約１０分間攪拌を行った。さらに造膜助剤（大阪有機化学工業（株）製、酢酸ブチル ジ ユーキゾール）１２ｇを加え、攪拌を５分間続け、白色塗料を得た。
【００９８】
実施例７
５００ｍＬのスチール製ビーカーに蒸留水１０．８ｇ、消泡剤（サンノプコ（株）製、ノプコ８０３４）０．４ｇを加え、１０００ｒｐｍで攪拌しながら、合成例１０の水性分散体（エマルジョン）２００ｇと合成例６の水性分散体（エマルジョン）１８０ｇを加えた。続いて、６０ｇの蒸留水と、増粘剤（旭電化工業（株）ＵＨ４２０、固形分６重量％）５．０ｇを加え、約１０分間攪拌を行った。さらに造膜助剤（大阪有機化学工業（株）製、酢酸ブチル ジ ユーキゾール）１２ｇを加え、攪拌を続けて白色塗料を得た。
【００９９】
比較実施例１
合成例１の水性分散体２００ｇにかえて、アクリル系エマルジョン（Ｇ−２５，固形分５０重量％，水谷ペイント（株）製）２００ｇを用い、白色塗料を得た。すなわち、５００ｍＬスチル製ビーカーに蒸留水１０．８ｇ、増粘剤５．０ｇ（６重量％，ＵＨ−４２０）、分散剤４．０ｇ（デモールＥＰ）、湿潤剤１．０ｇ（エマルゲン Ｌ４０）、消泡剤０．８ｇ（サンノプコ（株）製、ノプコ８０３４）を加えディスパーで１０００ｒｐｍで撹拌しながら、二酸化チタン８０ｇ（ＪＲ−６０３）を徐々に加えていった。回転数を３０００ｒｐｍにした後、１５分間撹拌を続けた。その後回転数を１０００ｒｐｍにした後、エマルジョン（Ｇ−２５，固形分５０重量％，水谷ペイント製）２００ｇを加えた。さらにコロイド状シリカ１５０ｇ（アデライトＡＴ−５０）を加え、さらに水６０ｇ及び造膜助剤（酢酸ブチル ジ ユーキゾール）１２ｇを加え１０分撹拌し白色塗料を得た。
【０１００】
比較実施例２
合成例１の水性分散体２００ｇにかえて、アクリル系エマルジョン（Ｇ−２５，５０重量％，水谷ペイント製）５０ｇおよびコロイダルシリカ（アデライトＡＴ−５０）１５０ｇを用い、白色塗料を得た。すなわち、５００ｍＬスチール製ビーカーに蒸留水１０．８ｇ、増粘剤５．０ｇ（６重量％，ＵＨ−４２０）、分散剤４．０ｇ（デモールＥＰ）、湿潤剤１．０ｇ（エマルゲン Ｌ４０）、消泡剤０．８ｇ（サンノプコ（株）製、ノプコ８０３４）を加えディスパーで１０００ｒｐｍで撹拌しながら、二酸化チタン８０ｇ（ＪＲ−６０３）を徐々に加えていった。回転数を３０００ｒｐｍにした後、１５分間撹拌を続けた。その後回転数を１０００ｒｐｍにした後、エマルジョン（Ｇ−２５，固形分５０重量％，水谷ペイント製）５０ｇ、さらにコロイダルシリカ（アデライトＡＴ−５０）１５０ｇを加えた。さらに水６０ｇ及び造膜助剤（酢酸ブチル ジ ユーキゾール）１２ｇを加え１０分撹拌し白色塗料を得た。
【０１０１】
比較実施例３〜５
表３に示す割合で、上記同様に塗料組成物を得た。
表３に上記実施例および比較実施例の塗料の組成を示す。
【０１０２】
実施例及び比較実施例の塗料について、次のようにして試料を作製した。
実施例及び比較実施例で得られた塗料１００重量部に水１５重量部を加え、試料調整後、７０×１５０ｍのスレート板に塗布量２００ｇ／ｍ²になるようスプレーガンで塗装し、常温で７日間放置して塗膜を形成した。
【０１０３】
Ｌ字型のステンレス製の汚染性用試験パネルは、上記と同様にスプレーガンで塗装し、常温７日間放置することにより作製した。なお、Ｌ字型のステンレス製パネルは、地面に対して垂直なプレート（幅２０ｃｍ×高さ３０ｃｍ）と、このプレートの上端部から角度１２０^oで斜め上方へ延びる傾斜プレート（幅２０ｃｍ×長さ７０ｃｍ）で構成されており、傾斜プレートの端部は支持可能であった。
【０１０４】
そして、下記のようにして、塗膜形成性、耐性、耐アルカリ性、耐沸性、耐凍害性、促進耐候性、屋外暴露試験、耐汚染性を評価したところ、表３に示す結果を得た。
【０１０５】
［試験方法および評価方法］
（１）貯蔵安定性
塗料１００ｇを２００ｍｌの容器に入れ、５０℃の熱風乾燥炉中に１０日間貯蔵し、塗料の状態を目視にて観察し、下記の基準で評価した。
【０１０６】
◎：全く増粘していないもの
○：わずかに増粘しているもの
△：増粘しているが塗装において問題を生じないもの
▲：著しく増粘し、塗装に適さないもの
×：ゲル化状態のもの
（２）光沢及び塗膜形成性
ドクタブレード（４ミル）でガラス板上に塗布し、室温で乾燥させ、塗膜を顕微鏡で観察し、下記の基準で評価した。塗膜の光沢を６０^o光沢として測定した。
【０１０７】
◎：５℃以下の温度でワレを生じないもの
○：ワレを生じないもの
▲：わずかにワレを生じるもの
×：著しくワレを生じているもの
（３）密着性
クロスカット２ｍｍ幅にてセロハンテープ剥離テストを行ない、碁盤目が全く剥離しない場合を１００／１００、碁盤目が全て剥離した場合を０／１００として表示した。
【０１０８】
（４）耐水性
水中へ２０日間浸漬し、塗膜の状態を目視により観察し、下記の基準で評価した。
【０１０９】
◎：塗膜の変化が全くなく、著しく良好
○：塗膜の変化がほとんどなく、良好
△：塗膜の変化が小さく、実用上問題ないレベル
▲：塗膜の変化がやや大きく、実用上やや問題の生じるレベル
×：塗膜の変化が大きく、実用性に乏しい
（５）耐アルカリ性
３０％ＮａＯＨ水溶液に７日間浸漬し、塗膜の状態を目視により観察し、上記（４）と同様の基準で評価した。
【０１１０】
（６）耐凍害性
水道水に浸漬した試験板を、−２０℃で１６時間、２０℃で８時間を１サイクルとする５０サイクルの凍結試験に供し、塗膜の状態を目視より観察し、上記（４）と同様の基準で評価した。
【０１１１】
（７）屋外暴露試験
１８カ月後の塗膜の外観（光沢、ワレ、変色）を観察し、上記（４）と同様の基準で評価した。また、光沢のグロス保持率も評価した。
【０１１２】
（８）汚染性
図に示したステンレス板に塗装し６カ月後、傾斜部、垂直部の変色により目視で観察し、上記（４）と同様の基準で評価した。
【０１１３】
（９）難燃性
塗料を長さ１５０ｍｍ、幅２０ｍｍ、厚さ１０ｍｍの型に流し込み、常温で１ヶ月放置した後、厚さを３．０ｍｍ±０．５ｍｍの試験片を調製した。この試験片を、ＪＩＳ Ｋ７２０１に準拠して試験を行い、燃焼する酸素指数値により以下の基準で難燃性を評価した。
【０１１４】
◎：２８以上
○：２６以上２８未満
△：２４以上２６未満
▲：２０以上２４未満
×：２０未満
【０１１５】
【表３】

【０１１６】
【表４】

【０１１７】
表３及び４に示されるように、実施例１〜５の塗料では、比較実施例１に比べて、耐汚染性、屋外暴露試験（耐候性）、耐水性などが１〜２ランク程度改善されている。また、実施例２と比較実施例２との対比から明らかなように、実施例２では、塗膜形成性、付着性、および耐性などを改善でき、バランスのとれた塗膜物性を示している。さらに、コロイド状シリカを含むエマルジョンを用いることにより、塗膜の光沢を広い範囲で調整可能である。さらには、コロイド状シリカの含有量の高いエマルジョン（合成例７，８）を用いた実施例２，３では、前記評価基準に基づいて、相対的に難燃性を評価したところ、難燃剤を添加することなく、難燃性を付与できる。
【０１１８】
また、合成例１０（微粒子として二酸化チタンを使用）を用いた実施例６の塗料では、二酸化チタンをポリマーによって被覆しているため、耐光性、耐水性、耐アルカリ性などにおいて、比較実施例１に比べて改善でき、バランスのとれた物性となっている。さらに、合成例１０（微粒子として二酸化チタンを使用）と、合成例６（微粒子としてコロイド状シリカ粒子を使用）とを用いた実施例７の塗料では、実施例６に比べて汚染性が、さらに改善されている。[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an aqueous dispersion composed of composite particles having inorganic or organic particles as a core and an organic polymer as a shell, and a method for producing the same, and the aqueous dispersion. The present invention relates to a coating composition which is high and can control gloss, mechanical properties and the like.
[0002]
[Prior art]
Colloidal silica is excellent in hardness, mechanical strength, antistatic property, chemical resistance, and weather resistance, and organic polymer is excellent in flexibility, adhesion, water resistance, etc. Complex aqueous compositions are known. For example, an aqueous coating material containing a mixture of a vinyl acetate emulsion, an acrylic emulsion, an acrylic-styrene emulsion, colloidal silica, a water-curable binder, or the like as a main component is known. However, these water-based coatings have a small bonding force between the organic polymer and the inorganic substance, and do not have long-term durability, film-forming properties, water resistance, and the like. In addition, in the coating composition using a blend system of the colloidal silica and the organic polymer as a binder, when the amount of the colloidal silica is increased, the film forming property is lowered, and the contamination property and the film forming property by the colloidal silica are high. It is difficult to achieve a balance between levels. Furthermore, when adjusting the gloss of the coating film, if a delustering agent such as silica or calcium carbonate is used, the water resistance, weather resistance, and mechanical properties are lowered as the amount of the delustering agent increases.
[0003]
In order to chemically bond colloidal silica as an inorganic substance and an organic polymer, Japanese Patent Application Laid-Open Nos. 59-71316 and 63-37168 are obtained by copolymerizing a silane monomer and colloidal silica. An aqueous resin dispersion is disclosed. In this dispersion, a chemical bond is formed between the colloidal silica and the silane monomer, so the compatibility and affinity between the inorganic substance and the organic polymer are good, and the water resistance, alkali resistance, and stain resistance are excellent. ing. However, because the resulting aqueous dispersion and paint have low stability and the coating film is non-uniform, the coating film has strong shrinkage and cohesion, and cracks may occur in the coating film. There are difficulties.
[0004]
Japanese Patent Application Laid-Open No. 9-194208 proposes that after colloidal silica and organoalkoxysilane are coupled, vinyl monomer is polymerized to produce an aqueous dispersion of core-shell composite particles. . However, when using colloidal silica having an average particle diameter of 50 nm or less that expresses good strength, appearance, and transparency as a coating film, it is difficult to obtain an aqueous dispersion having a solid content of 40% by weight or more, At a high solid content, the viscosity increases remarkably and the film formability is poor. Further, in order to obtain stable core-shell composite particles, it is necessary to use a large amount of a special silane compound having a methacryloyl group, which is disadvantageous in terms of cost. Furthermore, the total reaction time is 10 hours or more, and an aqueous dispersion or binder for coating cannot be produced industrially advantageously.
[0005]
Furthermore, the conventional method cannot provide stable core-shell composite particles having not only colloidal silica but also inorganic or organic particles as a core and an organic polymer as a shell.
[0006]
[Problems to be solved by the invention]
Accordingly, an object of the present invention is to provide an aqueous dispersion having good dispersion stability and storage stability, a high solid content concentration and high film formability, and a method for producing the same.
[0007]
Another object of the present invention is to provide an aqueous dispersion having excellent characteristics economically without using a special silane compound and a method for producing the same.
[0008]
Another object of the present invention is to provide an aqueous dispersion mainly composed of core-shell composite particles having inorganic or organic particles as a core and organic polymer as a shell, and a method for producing the same.
[0009]
Still another object of the present invention is to provide a method for producing an aqueous dispersion capable of controlling the amount of polymer single particles produced and the surface coverage of inorganic or organic particles.
[0010]
Another object of the present invention is to provide a coating composition that can maintain a film forming property, stain resistance, appearance and weather resistance at a high level and can form a highly durable coating film.
[0011]
Still another object of the present invention is to provide a coating composition capable of adjusting the gloss of a coating film without using a delustering agent.
[0012]
[Means for Solving the Problems]
In order to solve the above problems, the present inventors have intensively studied, and in a system in which inorganic or organic particles are dispersed in an aqueous medium in the presence of a nonionic surfactant, the clouding point of the nonionic surfactant or higher It has been found that when a vinyl monomer is polymerized at a temperature, the vinyl polymer is effectively bonded to the surface of the inorganic or organic particles, and an aqueous dispersion having high dispersion stability and film-forming properties can be obtained, thereby completing the present invention.
[0013]
    That is, the aqueous dispersion of the present invention is a system in which inorganic or organic particles are dispersed in an aqueous medium.The worldIn the presence of surfactant, BiAn aqueous dispersion obtained by polymerizing a nil monomer,The surfactant is selected from a first nonionic surfactant having a cloud point below the polymerization temperature, a second nonionic surfactant having a cloud point above the polymerization temperature, and an anionic surfactant. And at least one clouding point of the first nonionic surfactant, and when the second nonionic surfactant is used, the second nonionic surfactant A dispersion obtained by polymerizing a vinyl monomer at a temperature below the cloud point,The vinyl polymer binds to the surface of the inorganic or organic particles directly or via a nonionic surfactant.And having a core-shell structure with the inorganic or organic particles as a core and the vinyl polymer as a shell.The particles are dispersed in an aqueous medium. Inorganic or organic particles may be colloidal silica or pigments. SaidFirstAs the nonionic surfactant, polyoxyalkylene ether or a derivative thereof can be used,The cloud point of the first nonionic surfactant may be 0 to 80 ° C. The first nonionic surfactant may have at least one ethylenically unsaturated group.The vinyl polymer can be formed of a (meth) acrylic monomer, an aromatic vinyl monomer, a vinyl ester monomer, or the like.The ratio of the inorganic or organic particles and the first nonionic surfactant to 100 parts by weight of the vinyl polymer is 3 to 500 parts by weight of the inorganic or organic particles and 0.1 to 20 parts by weight of the first nonionic surfactant. Also good. Spherical composite particles having a core-shell structure in which 80% by weight or more of the particles have inorganic or organic particles as a core and a vinyl polymer as a shell may be used.In such an aqueous dispersion, the average particle size of the composite particles is 10 μm or less. The average particle size of the inorganic or organic particles may be 5 nm to 1 μm, and the average particle size of the composite particles may be 10 nm to 5 μm.
[0014]
  The aqueous dispersion is produced by polymerizing a vinyl monomer at a temperature equal to or higher than the cloud point of the nonionic surfactant in a system in which inorganic or organic particles are dispersed in an aqueous medium in the presence of the nonionic surfactant. it can.
  More specifically, it is a method for producing an aqueous dispersion by polymerizing a vinyl monomer in the presence of a surfactant in a system in which inorganic or organic particles are dispersed in an aqueous medium, wherein the surfactant At least one selected from a first nonionic surfactant having a cloud point below the polymerization temperature, a second nonionic surfactant having a cloud point above the polymerization temperature, and an anionic surfactant And a temperature higher than the cloud point of the first nonionic surfactant, and when the second nonionic surfactant is used, it is lower than the cloud point of the second nonionic surfactant. By polymerizing a vinyl monomer at a temperature, an aqueous dispersion in which composite particles having a core-shell structure with the inorganic or organic particles as a core and the vinyl polymer as a shell are dispersed in an aqueous medium can be produced. . In this method, the vinyl monomer may be polymerized by increasing the temperature above the cloud point of the first nonionic surfactant to adsorb the first nonionic surfactant on the surface of the inorganic or organic particles. .The polymerization temperature may be a temperature exceeding the cloud point of the nonionic surfactant (for example, 20 to 110 °, particularly 60 to 100 ° C.).The amount of the first nonionic surfactant used is
(a-1) Less than the critical micelle concentration and less than the saturated adsorption amount of inorganic or organic particles,
(a-2) Less than the critical micelle concentration, and more than the saturated adsorption amount of inorganic or organic particles,
(b-1) Greater than the critical micelle concentration and less than the saturated adsorption of inorganic or organic particles, or
(b-2) The vinyl monomer may be polymerized with a critical micelle concentration or higher and a saturated adsorption amount of inorganic or organic particles.
  The present invention also discloses a coating composition comprising the aqueous dispersion.This coating composition is composed of an aqueous dispersion in which the ratio of the composite particles having the core-shell structure and the inorganic or organic particles is the former / the latter = 100/0 to 50/50 (weight ratio) in terms of solid content. May be.
[0015]
DETAILED DESCRIPTION OF THE INVENTION
The composite particles constituting the aqueous dispersion of the present invention are composed of inorganic or organic particles and a vinyl polymer bonded to the surface of the inorganic or organic particles directly or via a nonionic surfactant. Is distributed. This composite particle of the dispersion system utilizes the fact that the nonionic surfactant is adsorbed on the particle surface at a temperature equal to or higher than the cloud point and provides a vinyl monomer polymerization field.
[0016]
In the present invention, fine particles are usually used as the particles.
[0017]
In the composite particles, the inorganic or organic particles constitute a core, and the polymer which is a vinyl polymer constitutes a shell. The shell portion of such an aqueous dispersion may contain other nonionic surfactants or anionic surfactants.
[0018]
[Inorganic particles]
As the inorganic particles, various functional particles such as silica, inorganic pigments, conductors (for example, gold, silver, platinum, aluminum, or alloys thereof), magnetic bodies (for example, ferrite) and the like can be used. These functional particles may be colloidal (for example, colloidal silica).
[0019]
(Colloidal silica particles)
As colloidal silica particles (colloidal silica), colloidal silica particles having an average particle diameter of 5 nm to 1 μm, preferably about 10 to 100 nm, can be used. Reference can be made to Japanese Patent Publication No. 57-9051 and Japanese Patent Publication No. 57-51653.
[0020]
Colloidal silica can be prepared and used by a sol-gel method, or a commercially available product can be used. When colloidal silica is prepared by the sol-gel method, Werner Stober et al; J. Colloid and Interface Sci., 26, 62-69 (1968), Rickey D. Badley et al; Langmuir 6, 792-801 (1990), Journal of Color Material Association, 61 [9] 488-493 (1988).
[0021]
Commercially available products of colloidal silica are from Nissan Chemical Co., Ltd., Snowtex-XL (average particle size 40-60 nm), Snowtex-YL (average particle size 50-80 nm), Snowtex-ZL (average particle size 70). ~ 100nm), PST-2 (average particle diameter 21nm), Snowtex 20 (average particle diameter 10-20nm, SiO₂/ Na₂O> 57), Snowtex 30 (average particle size 10-20 nm, SiO₂/ Na₂O> 50), Snowtex C (average particle size 10-20 nm, SiO₂/ Na₂O> 100), Snowtex O (average particle size 10-20 nm, SiO₂/ Na₂O> 500), Snowtex 50 (average particle size 20-30 nm), etc., available from Asahi Denka Kogyo Co., Ltd., Adelite AT-40 (average particle size 10-20 nm, solid content 40% by weight), Adelite AT -50 (average particle size 20-30 nm, solid content 50% by weight) etc.₂/ Na₂O is silicon dioxide and sodium hydroxide (Na₂The content weight ratio of (converted to O) is shown and described in the catalog). When using a commercial item, Adelite AT-40, AT-50, Snowtex 40, 50, etc. are preferable.
[0022]
The main component of colloidal silica is silicon dioxide, and it may contain alumina, sodium aluminate, etc. as a minor component. The colloidal silica may contain an inorganic base (such as sodium hydroxide, potassium hydroxide, lithium hydroxide, or ammonia) or an organic base (such as tetramethylammonium) as a stabilizer.
[0023]
(Inorganic pigment)
Examples of inorganic pigments include white pigments (eg, zinc oxide, lithopone, titanium oxide), yellow pigments (eg, chrome yellow, nickel titanium yellow, iron oxide yellow, yellow lead oxide), red pigments (eg, iron oxide red, Red lead oxide, molybdenum red, etc.), orange pigment (eg, molybdate orange, etc.), green pigment (eg, chrome green, chromium oxide, etc.), blue pigment (eg, bitumen, ultramarine blue, cobalt blue), purple pigment (eg, , Manganese violet, etc.), black pigments (for example, carbon black such as channel black and furnace black, black iron oxide, etc.).
[0024]
Further, extender pigments (for example, calcium carbonate, barium sulfate, aluminum hydroxide, etc.) may be used.
[0025]
[Organic particles]
As the organic particles, organic pigments, organic polymer particles (for example, silicone resins, polymethyl methacrylate resins, melamine resins, cross-linked styrene resins, etc.) can be used.
[0026]
(Organic pigment)
Organic pigments include azo pigments (e.g. yellow pigments such as Hansa Yellow, Benzidine Yellow, Vulcan Fast Yellow, Permanent Yellow, orange pigments such as Pyrazolone Orange, Vulcan Orange, Permanent Orange, Toluidine Red, Permanent Red, Brilliant Fast Scarlet, Vulcan Fast Red, Pyrazolone Red, Watching Red, Resor Red, Lake Red, Brilliant Carmine, Lake Bordeaux, etc. Pigments), lake pigments (eg, red pigments such as rhodamine lakes, methyl violet lakes, Victoria pure blue lakes) Blue pigments, green pigments such as final yellow green), and the like. Further, organic pigments such as quinacridone, perylene, isoindolinone, dioxazine, and selenium pigments may be used as the organic pigment.
[0027]
These inorganic or organic particles may be used alone or in combination of two or more. Usually, colloidal silica and pigment (inorganic or organic pigment) are used as the inorganic or organic particles.
[0028]
The average particle diameter of the inorganic or organic particles can be selected from a range of 5 μm or less (for example, 5 nm to 1 μm), preferably 10 nm to 0.5 μm, and more preferably about 20 nm to 0.2 μm. When the inorganic or organic particles are colloidal silica, the average particle diameter is 5 to 100 nm, preferably 10 to 80 nm, and more preferably about 10 to 50 nm. In the case of carbon black, the average particle size is 10 to 300 nm, preferably 20 to 100 nm, and more preferably about 30 to 80 nm.
[0029]
Moreover, these inorganic or organic particles may be surface-treated if necessary.
[0030]
[Nonionic surfactant]
In the composite particle, a vinyl polymer is bonded to the surface of the inorganic or organic particle directly or via a nonionic surfactant. The inorganic or organic particles are usually negatively charged and dispersed and stabilized in an aqueous medium. Therefore, in the present invention, after mixing the nonionic surfactant and the inorganic or organic particle dispersion at a temperature below the cloud point, the nonionic surfactant is applied to the surface of the inorganic or organic particle by setting the temperature to the cloud point or higher. Adsorbed to provide a field for vinyl monomer polymerization. In addition, although the inorganic or organic particle surface is usually hydrophilic, the particle surface can be hydrophobized by adsorption of a nonionic surfactant.
[0031]
In the present invention, the cloud point of the nonionic surfactant is the temperature at which the dispersion system becomes cloudy during the temperature rising process in a system in which inorganic or organic particles are dispersed in an aqueous medium in the presence of the nonionic surfactant. Means. The cloud point can be measured under each reaction condition because it is affected by the concentration of nonionic surfactant, the influence of the electrolyte, and the like. The cloud point of a nonionic surfactant is 0-80 degreeC, for example, Preferably it is 10-70 degreeC, More preferably, it is about 20-60 degreeC.
[0032]
Nonionic surfactants (dispersants or dispersion stabilizers) include, for example, proteins (gelatin, colloidal albumin, casein, lecithin, etc.), sugar derivatives (agar, starch derivatives, etc.), cellulose derivatives (hydroxymethylcellulose, etc.), many Esters of monohydric alcohol [ethylene glycol monofatty acid ester (eg, monoglycol ester of oleic acid, monoglycol ester of stearic acid), polyethylene glycol monofatty acid ester, propylene glycol monofatty acid ester, glycerin monofatty acid ester (eg, stearin Acid monoglyceride, etc.), glycerin difatty acid ester, sucrose fatty acid ester, sorbitan fatty acid ester (trade name span), etc.], synthetic hydrophilic polymers such as polyvinyl alcohol, End-chain alkyl group-modified polyvinyl alcohol, vinyl polymer [(meth) acrylic acid hydroxyalkyl ester, alkyl vinyl ether, vinyl acetate, (meth) acrylamide, diacetone acrylamide, etc., a monomer having at least one ethylenically unsaturated group Homopolymer or Copolymer Containing Body as a Constituent], Polyoxyalkylene (Polyoxyethylene, Polyoxypropylene) or Derivatives thereof [Polyoxyethylene Alkyl Ether, Polyoxyethylene Alkyl Aryl Ether, Alkylene Oxide Adduct of the Fatty Acid Ester (For example, polyoxyethylene glycerin fatty acid ester, polyoxyethylene sucrose fatty acid ester, polyoxyethylene sorbitan aliphatic ester (trade name Tween), etc.)] and the like. As the dispersant, a graft polymer, a block polymer, or a macromer in which an anchor group and a dispersion stabilizing group are separated may be used. These nonionic surfactants can be used alone or in combination of two or more.
[0033]
When a nonionic surfactant having an unsaturated bond (for example, vinyl, isopropenyl, (meth) acryloyl, etc.) is used, the nonionic surfactant adsorbed on the inorganic or organic particle surface and the vinyl monomer can be polymerized.
[0034]
Preferred nonionic surfactants include polyoxyethylene alkyl ethers [for example, polyoxyethylene lauryl ether (manufactured by Kao Corporation, Emulgen 108, cloud point 40 ° C.), polyoxyethylene stearyl ether (manufactured by Kao Corporation), Emulgen 409P, cloud point 55 ° C) and other polyoxyethylene C_6-20Alkyl ether], polyoxyethylene alkyl phenyl ether [for example, polyoxyethylene octyl phenyl ether, polyoxyethylene lauryl phenyl ether, polyoxyethylene nonyl phenyl ether (manufactured by Kao Corporation, Emulgen 909, cloud point 40 ° C.), etc. Polyoxyethylene C_6-20Alkylphenyl ether, etc.], polyoxyethylene sucrose C_12-20Fatty acid ester, polyoxyethylene sorbitan C_12-20Fatty acid ester, polyoxyalkylene block copolymer [for example, polyoxyethylene-polyoxypropylene block copolymer (Asahi Denka Kogyo Co., Ltd., Pluronic L61, cloud point 24 ° C., pluronic L-64, cloud point 58 ° C. ), Etc.], polyoxyethylene C having at least one ethylenically unsaturated group (polymerizable unsaturated group) such as an allyl group_6-20Alkyl phenyl ethers [for example, 1-allyloxymethyl-2-nonylphenyloxyethanol ethylene oxide adduct (manufactured by Asahi Denka Kogyo Co., Ltd., NE-10, cloud point 40 ° C.) and the like] and the like are included.
[0035]
The hydrophilic-lipophilic balance (HLB) of the nonionic surfactant can be selected within a wide range, and is, for example, 1 to 30, preferably 3 to 25, and more preferably about 5 to 20.
[0036]
The amount of the nonionic surfactant used is 0.1 to 20 parts by weight, preferably 0.5 to 15 parts by weight, and more preferably 1 to 10 parts by weight in terms of solid content with respect to 100 parts by weight of the vinyl polymer described below. About parts by weight.
The nonionic surfactant may be referred to as a first nonionic surfactant.
[0037]
[Vinyl polymer]
The vinyl polymer can be formed of a conventional polymerizable monomer, and may be a homopolymer or a copolymer. The monomer that forms the vinyl polymer (vinyl monomer) includes at least one radically polymerizable monomer having an ethylenically unsaturated group, such as a (meth) acrylic monomer, an aromatic vinyl-based monomer. Monomers, vinyl ester monomers and the like are included. These monomers can be used alone or in combination of two or more.
[0038]
Examples of vinyl monomers include (meth) acrylic acid alkyl esters [methyl (meth) acrylate, ethyl (meth) acrylate, n- or i-propyl (meth) acrylate, 2-methyl-2-nitropropyl ( (Meth) acrylate, n-, i-, s- or t-butyl (meth) acrylate, n- or t-pentyl (meth) acrylate, 3-pentyl (meth) acrylate, 2,2-dimethylbutyl (meth) acrylate , N-hexyl (meth) acrylate, cetyl (meth) acrylate, n-octyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, 4-methyl-2-propylpentyl (meth) acrylate, n-octadecyl (meth) (Meth) acrylic acid C such as acrylate_1-20Alkyl esters], cycloalkyl (meth) acrylate [cyclohexyl (meth) acrylate, cyclopentyl (meth) acrylate, etc.], aralkyl (meth) acrylate [benzyl (meth) acrylate, etc.], polycyclic (meth) acrylate [2- Isobornyl (meth) acrylate, 2-norbornylmethyl (meth) acrylate, 5-norbornen-2-yl-methyl (meth) acrylate, 3-methyl-2-norbornylmethyl (meth) acrylate, etc.], hydroxyl group Containing (meth) acrylic acid esters [hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, 2,3-dihydroxypropylmethyl-butyl (meth) methacrylate, etc.], alkoxy group or phenoxy group (Meth) acrylic acid esters [2-methoxyethyl (meth) acrylate, 2-ethoxyethyl (meth) acrylate, 2-methoxymethoxyethyl (meth) acrylate, 3-methoxybutyl (meth) acrylate, ethyl carbitol (meth) Acrylate, phenoxyethyl (meth) acrylate, etc.], epoxy group-containing (meth) acrylates [such as glycidyl (meth) acrylate], halogen-containing (meth) acrylates [2,2,2-trifluoroethyl ( (Meth) acrylate, 2,2,2-trifluoroethylethyl (meth) acrylate, tetrafluoropropyl (meth) acrylate, hexafluoropropyl (meth) acrylate, octafluoropentyl (meth) acrylate, heptadecafluoro Sil (meth) acrylate, etc.], (meth) acrylamides [e.g., (meth) acrylamide, N-methyl (meth) acrylamide, Nn-butyl (meth) acrylamide, Ni-propyl (meth) acrylamide, N -T-butyl (meth) acrylamide, N, N-dimethyl (meth) acrylamide, 2- (meth) acrylamide-2-methylpropanesulfonic acid, (meth) acrylamidepropyltrimethylammonium chloride, diacetone (meth) acrylamide, (meta ) Acryloylmorpholine, N-methylol (meth) acrylamide, etc.], alkylaminoalkyl (meth) acrylate [dimethylaminoethyl (meth) acrylate, etc.], vinyl cyanides [(meth) acrylonitrile, etc.], vinyl ester (For example, vinyl acetate), aromatic vinyl compounds (for example, styrene, p-chlorostyrene, t-butylstyrene, α-methylstyrene, sodium styrenesulfonate), carboxyl group-containing monomers or salts thereof [(Meth) acrylic acid, itaconic acid, maleic acid, fumaric acid or salts thereof], sulfonic acid group-containing monomer or salt thereof [vinyl sulfonic acid, sodium vinyl sulfonate, sodium allyl sulfonate, methallyl sulfonic acid Sodium, etc.], unsaturated polyvalent carboxylic acid derivatives (esters such as dimethyl maleate, dibutyl maleate, diethyl fumarate, N-substituted maleimides such as N-phenylmaleimide), N-vinyl polyvalent carboxylic acid imide [ N-vinylsuccinimide etc.], dienes (for example, butadiene, Clopentadiene, isoprene), heterocyclic vinyl monomers (N-vinylpyrrolidone, N-vinyloxazolidone, 1-vinylimidazole, 4-vinylpyridine, etc.), N-vinylamides (N-vinylformamide, N-vinyl- N-methylformamide, N-vinylacetamide, N-vinyl-N-methylacetamide, etc.), halogen-containing vinyl monomers (vinyl chloride, bilidene chloride, etc.), vinyl alkyl ethers (eg, methyl vinyl ether, etc.), olefins (Ethylene, propylene, 1-butene, isobutene, etc.) and the like. These vinyl monomers can be used alone or in combination of two or more.
[0039]
Preferred vinyl monomers include (meth) acrylic monomers, aromatic vinyl monomers, vinyl ester monomers, and the like. In particular, at least (meth) acrylic monomers are often used.
[0040]
The vinyl monomer may be used in combination with a polyfunctional vinyl monomer having two or more unsaturated groups. Examples of the polyfunctional vinyl monomer include divinylbenzene, 4,4′-isopropylidene diphenylene di (meth) acrylate, 1,3-butylene di (meth) acrylate, 1,4-cyclohexylenedimethylene (meta ) Acrylate, ethylene glycol di (meth) acrylate, diethylene glycol di (meth) acrylate, triethylene glycol di (meth) acrylate, tetraethylene glycol di (meth) acrylate, tetramethylene di (meth) acrylate, diisopropylidene glycol di ( (Meth) acrylate, divinyloxymethane, ethylidene di (meth) acrylate, allyl (meth) acrylate, 1,6-di (meth) acrylamide hexane, N, N′-methylenebis (meth) acrylamide, N, N- ( , 2-dihydroxy) ethylenebis (meth) acrylamide, 2,2-dimethyl-1,3-trimethylene di (meth) acrylate, phenylethylene di (meth) acrylate, 2,2,2-trichloroethylidene di (meth) acrylate, Pentaerythritol tri (meth) acrylate, trimethylolpropane tri (meth) acrylate, tetramethylolmethane tetra (meth) acrylate, 1,3,5-tri (meth) acryloylhexahydro-s-triazine, bis (meth) acrylamide acetic acid Ethylidine tri (meth) methacrylate, propyridine tri (meth) acrylate, vinylallyloxyacetate and the like. These polyfunctional vinyl monomers can also be used alone or in combination. Of these polyfunctional vinyl monomers, divinylbenzene and a monomer having two or more (meth) acryloyl groups (such as ethylene glycol di (meth) acrylate) are generally used.
[0041]
In the dispersion system, it is preferable that the nonionic surfactant is adsorbed on the surface of the inorganic or organic particles during the polymerization of the vinyl monomer. Accordingly, the polymerization temperature of the vinyl monomer is preferably a temperature exceeding the cloud point of the nonionic surfactant, for example, 20 to 110 ° C., preferably 30 to 100 ° C., more preferably 60 to 100 ° C., particularly It is about 70-90 degreeC.
[0042]
The vinyl monomer can be selected according to the properties required for the coating film (film forming property, glass transition temperature, etc.), and usually has a glass transition temperature of −30 ° C. to 80 ° C., preferably −20 ° C. to A vinyl polymer is formed at 50 ° C., particularly about 0 to 50 ° C. Moreover, in order to comprise a bridge | crosslinking system, you may use the vinyl monomer which has reactive groups, such as a hydroxyl group, a carboxyl group, an acid anhydride group, and a glycidyl group.
[0043]
The ratio between the vinyl polymer and the inorganic or organic particles can be selected according to the film-forming properties, for example, 3 to 500 parts by weight, preferably 10 to 300 parts by weight of the inorganic or organic particles with respect to 100 parts by weight of the vinyl polymer. Part by weight, more preferably about 20 to 200 parts by weight (for example, 30 to 200 parts by weight).
[0044]
[Aqueous dispersion]
The average particle size of the composite particles composed of such components varies depending on the size of the core inorganic or organic particles, but is, for example, 10 μm or less (for example, 10 nm to 10 μm), preferably 50 nm to 5 μm (for example, 80 nm to 5 μm), more preferably about 0.1 to 1 μm. If the average particle diameter is in the above range, the dispersion stability of the composite particles is high. When the inorganic or organic particles are colloidal silica, the average particle size of the composite particles is 10 to 500 nm, preferably 20 to 300 nm (for example, 20 to 250 nm), particularly about 30 to 200 nm. In the case of carbon black, the average particle size is about 10 nm to 1 μm, preferably about 30 nm to 0.5 μm, and more preferably about 50 nm to 0.3 μm.
[0045]
The proportion of each component is, for example, about 0.1 to 20 parts by weight (for example, 0.5 to 10 parts by weight) of a nonionic surfactant and 3 to 500 parts by weight of inorganic or organic particles with respect to 100 parts by weight of the vinyl polymer. Part (for example, 100 to 500 parts by weight).
[0046]
In the aqueous dispersion, it is not necessary that all of the dispersed particles are the core-shell composite particles, but a mixture of the core-shell composite particles and at least one kind of particles selected from vinyl polymer particles and inorganic or organic particles. There may be. In a preferred aqueous dispersion, 80% by weight or more of the particles are composed of composite particles having a core-shell structure in which inorganic or organic particles are the core and vinyl polymer is the shell.
[0047]
[Method for producing aqueous dispersion]
The aqueous dispersion of the present invention contains a vinyl monomer at a temperature above the cloud point in a system in which inorganic or organic particles are dispersed in an aqueous medium in the presence of a nonionic surfactant (first nonionic surfactant). It can be obtained by polymerization. In particular, after mixing the first nonionic surfactant and the inorganic or organic particle dispersion at a temperature lower than the cloud point, the temperature is raised to a temperature equal to or higher than the cloud point, and the first nonionic surface activity on the surface of the inorganic or organic particles. By adsorbing the agent and polymerizing the vinyl monomer, composite particles in which inorganic or organic particles and vinyl polymer are effectively bonded can be obtained.
[0048]
In the dispersion system, as the first nonionic surfactant is adsorbed on the surface of the inorganic or organic particles, or as the polymerization of the vinyl monomer proceeds, the inorganic or organic particles become hydrophobic, and the dispersion stability is reduced to agglomerate. It may gel. Therefore, a second nonionic surfactant may be added to the reaction system in order to disperse and stabilize hydrophobicized inorganic or organic particles in an aqueous medium. The second nonionic surfactant may be added at the beginning of mixing, or may be added at the time of temperature increase, at the beginning of polymerization, or after polymerization. Preferably, the second nonionic surfactant is preferably added after the temperature becomes higher than the cloud point of the first nonionic surfactant.
[0049]
The cloud point of the second nonionic surfactant often exceeds the cloud point of the first nonionic surfactant in order to disperse and stabilize the inorganic or organic particles adsorbed by the first nonionic surfactant. Furthermore, in order to stabilize the inorganic or organic particles in the process of polymerization of the vinyl monomer, it is preferable to have a cloud point that exceeds the polymerization temperature. The second nonionic surfactant is oriented on the surface of the hydrophobic inorganic or organic particles, stabilizes the inorganic or organic particles, and further, together with the first nonionic surfactant, allows the polymerization of the vinyl monomer. provide.
[0050]
The amount of the second nonionic surfactant used is preferably equal to or lower than the critical micelle concentration (CMC) in order to prevent formation of vinyl polymer single particles by forming micelles. In many cases, the amount is 0.01 to 5 parts by weight, preferably 0.1 to 3 parts by weight, and more preferably about 0.1 to 2 parts by weight with respect to 100 parts by weight of the inorganic or organic particles.
[0051]
Moreover, you may use the anionic surfactant generally used for emulsion polymerization for dispersion stabilization. In order to effectively adsorb the first nonionic surfactant on the surface of the inorganic or organic particles, the anionic surfactant is added after the first nonionic surfactant is adsorbed on the surface of the inorganic or organic particles. Is preferred. For example, the anionic surfactant may be added after the nonionic surfactant is uniformly adsorbed on the inorganic or organic particles, or after the vinyl monomer is polymerized to form stabilized seed-like composite particles. . As described above, since inorganic or organic particles are usually negatively charged in an aqueous medium, the adsorption efficiency with an anionic surfactant is expected to be low, but anionic surface activity having a negative charge is expected. The agent may form micelles alone with respect to negatively charged inorganic or organic particles. Therefore, when an anionic surfactant is added at the initial stage of mixing, a large number of polymer single particles may be generated.
[0052]
In the present invention, the vinyl monomer can be polymerized by various methods that can be polymerized in the dispersion. A preferred polymerization method is an emulsion polymerization method in which a vinyl monomer is polymerized in an aqueous medium (particularly water). In the emulsion polymerization method, a method in which a vinyl monomer is charged into a reaction system continuously or stepwise is preferable. In the presence of a nonionic surfactant, if monomers are charged all together in a system in which inorganic or organic particles are dispersed, the possibility of generating core-shell composite particles may be reduced. This is because the adsorbed nonionic surfactant is dissolved in the monomer oil droplets, and the nonionic surfactant adsorbed on the surface of the inorganic or organic particles is reduced. In addition, after stable particles are generated as seeds, vinyl monomers may be charged all at once. Moreover, when adding a monomer to a reaction system, the composition of a monomer may be the same and may be changed.
[0053]
As the polymerization initiator, a peroxide (for example, hydrogen peroxide), a persulfate (for example, potassium persulfate, ammonium persulfate), an aqueous azo compound or a redox polymerization initiator can be used.
[0054]
In the polymerization of the present invention, a chain transfer agent such as an organic peroxide soluble in a vinyl monomer, an organic azo compound, a halogenated hydrocarbon (such as carbon tetrachloride), a mercaptan is used for adjusting the molecular weight of the polymer. And thiols may be used. The amount of chain transfer agent used is, for example, 5% by weight or less based on the vinyl monomer.
[0055]
If necessary, in order to increase the dispersion stability of inorganic or organic particles, a pH adjuster (for example, acid (sulfuric acid, hydrochloric acid, etc.), ammonia, amine, etc.) is added to the aqueous dispersion after the polymerization process or reaction. It may be added. The pH of the polymerization system or aqueous dispersion may be adjusted to, for example, about pH 7-9 (for example, 7.5-8.5).
[0056]
In the present invention, the ratio of the core-shell composite particles / vinyl polymer particles / inorganic or organic particles can be arbitrarily adjusted by adjusting the cloud point, critical micelle concentration (CMC), or amount used of the nonionic surfactant in combination. You can control.
[0057]
That is, in a system in which inorganic or organic particles are dispersed in an aqueous medium, when a vinyl monomer is polymerized at a temperature equal to or higher than the cloud point of the nonionic surfactant, an aqueous dispersion mainly comprising at least core-shell composite particles. You can get a body. Furthermore, when the vinyl monomer is polymerized at a nonionic surfactant concentration less than the critical micelle concentration (CMC) (a), the nonionic surfactant can be effectively adsorbed on the inorganic or organic particles, and the core-shell structure The composite particles can be obtained. On the other hand, when the nonionic surfactant concentration is equal to or higher than the critical micelle concentration (b), micelles may be formed as a polymerization site for vinyl monomers to form vinyl polymer particles.
[0058]
Further, when the amount of the nonionic surfactant used is less than the saturated adsorption amount for the inorganic or organic particles (1), normal inorganic or organic particles are produced, and if the saturated adsorption amount is equal to or greater than the saturated adsorption amount (2), at least the core -An aqueous dispersion mainly composed of composite particles having a shell structure can be obtained.
[0059]
As described above, in the present invention that polymerizes at a temperature higher than the cloud point of the nonionic surfactant, by adjusting the type and concentration of the nonionic surfactant, core-shell composite particles / vinyl polymer particles / inorganic or organic The proportion of particles can be controlled. More specifically, it is as follows.
[0060]
(A-1) When the concentration of the nonionic surfactant is less than the critical micelle concentration (CMC) and less than the saturated adsorption amount with respect to the inorganic or organic particles, the composite particles / inorganic or organic particles having a core-shell structure An aqueous dispersion composed of a mixture is obtained.
[0061]
(A-2) When the concentration of the nonionic surfactant is less than the critical micelle concentration and is equal to or greater than the saturated adsorption amount with respect to the inorganic or organic particles, an aqueous dispersion mainly composed of the core-shell composite particles is obtained. Can do.
[0062]
When the concentration of (b-1) nonionic surfactant is not less than the critical micelle concentration and less than the saturated adsorption amount for inorganic or organic particles, the composite particles / vinyl polymer particles / inorganic or organic particles are used. An aqueous dispersion composed of a component system can be obtained.
[0063]
Furthermore, when the concentration of (b-2) nonionic surfactant is not less than the critical micelle concentration and not less than the saturated adsorption amount for inorganic or organic particles, an aqueous dispersion composed of a mixture of composite particles / vinyl polymer particles You can get a body.
[0064]
In the present specification, the critical micelle concentration (CMC) means a concentration at which micelles are generated in the aqueous phase when a nonionic surfactant is added in the presence of inorganic or organic particles. This critical micelle concentration varies depending on the content of inorganic or organic particles, electrolyte concentration, etc., but from the relationship between the surfactant concentration and the surface tension, an indicator of the apparent critical micelle concentration that makes the surface tension minimum It can be. For example, the presence of these components increases the critical micelle concentration of the nonionic surfactant as compared to when no inorganic or organic particles or electrolyte are present. The saturated adsorption amount can be measured in advance by a conventional method. In the case of inorganic or organic particles having an average particle diameter of 50 nm or less, the amount may be about 0.5 to 5 parts by weight (for example, 1 to 2 parts by weight) with respect to 100 parts by weight of inorganic or organic particles in terms of solid content. Many.
[0065]
The solid content concentration of the aqueous dispersion can be selected according to the use and the like, and is, for example, about 10 to 60% by weight, preferably about 30 to 55% by weight, and particularly about 45 to 55% by weight.
[0066]
The aqueous dispersion obtained by such a method can form a coating film excellent in high film forming property, stain resistance, heat resistance, etc. even if the content of inorganic or organic particles is 50% by weight. Further, the ratio of the core-shell composite particles / vinyl polymer particles / inorganic or organic particles can be controlled, and a highly glossy coating film or matte coating film can be formed. Therefore, the composition composed of the aqueous dispersion of the present invention is useful as a film molding material (coating agent), particularly as a coating composition. In the aqueous dispersion, when the ratio of the composite particles to the inorganic or organic particles is changed in a range of composite particles / inorganic or organic particles = 100/0 to 50/50 (weight ratio in terms of solid content), Gloss (gloss) at an incident angle of 60 ° can be adjusted in the range of about 85 to 3 without using a delustering agent such as silica.
[0067]
In the coating composition (aqueous coating composition) of the present invention, various components commonly used in aqueous coatings, such as dispersants, wetting agents, thickeners, plasticizers, surface conditioners, antifoaming agents, viscosity adjustments. Agents, flame retardants, antistatic agents, water-soluble organic solvents, etc. can be used. If necessary, the coating composition may contain a pigment. As the above-mentioned pigments, the above-mentioned inorganic or organic pigments (for example, colored pigments such as titanium dioxide and phthalocyanine blue, extender pigments such as calcium carbonate and barium sulfate) may be used, and brightness such as aluminum powder and mica flakes may be used. An agent or the like may be used. The pigment weight concentration (PWC) in the coating composition is usually about 1 to 70% by weight, preferably about 10 to 65% by weight, and more preferably about 20 to 60% by weight in terms of solid content. When the solid content concentration is less than 1% by weight, the concealability is lowered, and when it exceeds 70% by weight, the gloss of the coating film is lowered, the viscosity is increased, and the water resistance and mechanical strength are liable to be lowered.
[0068]
Among the coating compositions, the coating composition containing composite particles (also functioning as a binder) as the main component (80% by weight or more) is composed of inorganic or organic particles 3 to 500 with respect to 100 parts by weight of the vinyl monomer. It has a high film-forming property in a wide range of about parts by weight (preferably 50 to 500 parts by weight, more preferably 100 to 500 parts by weight), and has excellent stain resistance and flame retardancy. In particular, a coating composition having a high content of inorganic or organic particles can exhibit high flame retardancy without using a flame retardant.
[0069]
If necessary, a water-soluble or water-dispersible binder resin, a crosslinking agent, a curing agent, a crosslinking or curing aid, and the like may be added to the coating composition of the present invention. When the coating composition of the present invention is applied to a substrate by a conventional method and dried or cured, a highly durable coating film can be formed.
[0070]
【The invention's effect】
In the present invention, since the aqueous dispersion contains the composite particles (particularly core-shell composite particles having inorganic or organic particles as the core and organic polymer as the shell), the dispersion stability and storage stability are high, and the solid content concentration Even if the film thickness is high, the film forming property can be improved. In addition, an aqueous dispersion having excellent advantageous properties economically can be obtained without using a special silane compound.
[0071]
In the coating composition of the present invention, the film-forming property and the stain resistance and weather resistance, which could not be achieved as conventional water-based paints, can be maintained at a high level, and the coating film having high water resistance, weather resistance and high durability can be obtained. Can be formed. In addition, a composition having a high composition ratio of inorganic or organic particles can greatly improve heat resistance and flame retardancy while maintaining high film formability. Furthermore, the production amount of vinyl polymer particles and the surface coverage of inorganic or organic particles can be controlled, and the composition ratio of composite particles / vinyl polymer particles / inorganic or organic particles can be adjusted. Therefore, the gloss of the coating film can be adjusted without using a matting agent.
[0072]
【Example】
Hereinafter, the present invention will be described in more detail based on synthesis examples, examples, and comparative examples, but the present invention is not limited to these examples.
[0073]
Synthesis example 1
To a 1000 mL glass four-necked flask equipped with a stirrer, thermometer, dropping funnel and reflux condenser, distilled water 100 g and colloidal silica (Asahi Denka Kogyo Co., Ltd., Adelite AT-50, solid content 50 weight) %, Average particle diameter 20-30 nm) 200 g was added, and the first nonionic surfactant (Asahi Denka Kogyo Co., Ltd., NE-10, cloud point 40 ° C., reactivity) 3.0 g was stirred under a nitrogen stream. While adding. 2N-H₂SO_FourAfter adjusting the pH to 8 to 8.5, the temperature was raised to 70 ° C. 0.6 g of ammonium persulfate was added, and 5 g of vinyl monomer of methyl methacrylate (MMA) / n-butyl acrylate (n-BA) / methacrylic acid (MAA) = 49/50/1 (weight ratio) was added. Added dropwise for 60 minutes and left for 60 minutes. Furthermore, 2.1 g of a second nonionic surfactant (manufactured by Kao Corporation, Emulgen 840S, solid content 70% by weight, cloud point of 100 ° C. or higher) was added, and MMA / n-BA / MAA = 49 at a temperature of 70 ° C. 95 g of vinyl monomer of / 50/1 (weight ratio) was added dropwise over 4 hours. The reaction temperature was maintained at 70 ° C, and after completion of the dropwise addition, the reaction was further maintained at 70 ° C for 1 hour and stirring was continued. Thereafter, the mixture was cooled and adjusted to pH 8.5 with 25 wt% aqueous ammonia to obtain 402 g of a composite fine particle dispersion (yield 98%, solid content 50 wt%, average particle diameter 81 nm).
[0074]
Synthesis example 2
To a 1000 mL glass four-necked flask equipped with a stirrer, thermometer, dropping funnel and reflux condenser, 100 g of distilled water and colloidal silica (manufactured by Nissan Chemical Co., Ltd., Snowtex 50, solid content 50% by weight, 300 g of an average particle size of 20 to 30 nm), a first nonionic surfactant (manufactured by Asahi Denka Kogyo Co., Ltd., NE-10, cloud point 40 ° C., reactivity) under a nitrogen stream, a second surfactant (Kao Co., Ltd., Emulgen 840S, solid content 70 wt%, cloud point of 100 ° C. or higher) was added with stirring 4.5 g and 2.5 g, respectively. 2N-H₂SO_FourAfter adjusting the pH to 8 to 8.5, the temperature was raised to 70 ° C. 0.6 g of ammonium persulfate was added, and 10 g of vinyl monomer of MMA / n-BA / styrene (St) / MAA = 29/50/20/1 (weight ratio) was added dropwise for 10 minutes and left for 60 minutes. did. Then, after adding 2.0 g of an anionic surfactant (Eoal 20C, solid content 25 wt%, manufactured by Kao Corporation), MMA / n-BA / St / MAA = 29/50/20/1 (weight ratio) ) Was added dropwise at 70 ° C. over 4 hours. The reaction temperature was maintained at 70 ° C, and after completion of the dropwise addition, the mixture was further maintained at 70 ° C for 1 hour and stirring was continued. Thereafter, the mixture was cooled and adjusted to pH 8.5 with 25% by weight aqueous ammonia to obtain 501 g of a composite fine particle dispersion (yield 98%, solid content 50% by weight, average particle size 66 nm).
[0075]
Synthesis Example 3 [Composite particle / polymer particle]
In a 1000 mL glass four-necked flask equipped with a stirrer, thermometer, dropping funnel and reflux condenser, distilled water 100 g, colloidal silica (Asahi Denka Kogyo Co., Ltd., Adelite AT-50, solid content 50 weight) %, Average particle diameter 20-30 nm) 200 g, under a nitrogen stream, the first nonionic surfactant (Asahi Denka Kogyo Co., Ltd., Pluronic L-64, cloud point 58 ° C.), the second surfactant (Kao Co., Ltd., Emulgen 840S, solid content 70% by weight, cloud point of 100 ° C. or higher) were added with stirring at 3.0 g and 6.2 g, respectively. 2N-H₂SO_FourAfter adjusting the pH to 8 to 8.5, the temperature was raised to 70 ° C. 0.6 g of ammonium persulfate was added, and 10 g of vinyl monomer of MMA / n-BA / MAA = 49/50/1 (weight ratio) was added dropwise for 10 minutes and left for 60 minutes. Then, after adding 2.0 g of an anionic surfactant (Eoal 20C, solid content 25% by weight, manufactured by Kao Corporation), vinyl unit of MMA / n-BA / MAA = 49/50/1 (weight ratio) 90 g of the monomer was added dropwise at 70 ° C. over 4 hours. The reaction temperature was maintained at 70 ° C., and after completion of the dropwise addition, the mixture was further maintained at 70 ° C. for 1 hour and stirring was continued. Thereafter, the mixture was cooled and adjusted to pH 8.5 with 25% by weight aqueous ammonia to obtain 400 g of an aqueous dispersion (yield 98%, solid content 50% by weight, average particle diameter 69 nm).
[0076]
Synthesis Example 4 [Composite Particle / Colloidal Silica Particle]
In a 1000 mL glass four-necked flask equipped with a stirrer, thermometer, dropping funnel and reflux condenser, 100 g of distilled water, colloidal silica (Nissan Chemical Co., Ltd., Snowtex 50, solid content 50% by weight, 200 g of an average particle diameter of 20 to 30 nm) was added, and 0.8 g of a nonionic surfactant (Asahi Denka Kogyo Co., Ltd., Pluronic L-61, cloud point 24 ° C.) was added under stirring in a nitrogen stream. 2N-H₂SO_FourAfter adjusting the pH to 8 to 8.5, the temperature was raised to 70 ° C. 0.6 g of ammonium persulfate was added, and 10 g of vinyl monomer of MMA / n-BA / 2-ethylhexyl acrylate (2-EHA) / MAA = 49/20/30/1 (weight ratio) was added dropwise for 10 minutes. And left for 60 minutes. Thereafter, 1.5 g of an anionic surfactant (Kao Co., Ltd., Emar 20C, solid content 25% by weight) was added, and at a temperature of 70 ° C., MMA / n-BA / 2-EHA / MAA = 49/20 / 90 g of 30/1 (weight ratio) vinyl monomer was added dropwise over 4 hours. The reaction temperature was maintained at 70 ° C, and after completion of the dropwise addition, the reaction was further maintained at 70 ° C for 1 hour and stirring was continued. Thereafter, the mixture was cooled and adjusted to pH 8.5 with 25 wt% aqueous ammonia to obtain 399 g of an aqueous dispersion (yield 98%, solid content 50 wt%, average particle diameter 90 nm).
[0077]
Synthesis Example 5 [Composite particle / polymer particle / colloidal silica particle]
In a 1000 mL glass four-necked flask equipped with a stirrer, thermometer, dropping funnel and reflux condenser, distilled water 5.0 g, colloidal silica (Nissan Chemical Co., Ltd., Snowtex 40, solid content 40 weight) %, Average particle size 10 to 20 nm) 250 g, and under a nitrogen stream, the first nonionic surfactant (Asahi Denka Kogyo Co., Ltd., NE-10, cloud point 40 ° C., reactivity), second nonionic Surfactants (manufactured by Kao Corporation, Emulgen 840S, cloud point of 100 ° C. or higher, solid content of 70% by weight) were added with stirring at 0.8 g and 6.2 g, respectively. 2N-H₂SO_FourAfter adjusting the pH to 8 to 8.5, the temperature was raised to 70 ° C. 0.6 g of ammonium persulfate was added, and 5 g of vinyl monomer of MMA / n-BA / St / MAA = 29/50/20/1 (weight ratio) was added dropwise over 10 minutes and left for 60 minutes. . Thereafter, 1.5 g of an anionic surfactant (Eoal 20C, solid content 25% by weight, manufactured by Kao Corporation) was added, and then MMA / n-BA / St / MAA = 29/50/20/1 (weight ratio) ) Was added dropwise at 70 ° C. over 4 hours. The reaction temperature was maintained at 70 ° C, and after completion of the dropwise addition, the reaction was further maintained at 70 ° C for 1 hour and stirring was continued. Thereafter, the mixture was cooled and adjusted to pH 8.5 with 25 wt% aqueous ammonia to obtain 399 g of an aqueous dispersion (yield 98%, solid content 50 wt%, average particle diameter 82 nm).
[0078]
Synthesis Examples 6-8
Using the components shown in Table 1, an aqueous dispersion was obtained in the same manner as in the above synthesis example.
[0079]
Synthesis Example 9
In a 500 mL steel beaker, 240 g of distilled water, the first nonionic surfactant (manufactured by Asahi Denka Kogyo Co., Ltd., NE-10, cloud point 40 ° C., reactivity), the second nonionic surfactant (Kao Corporation ), Emulgen 840S, solid content 70% by weight, cloud point 100 ° C. or higher) 2.4 g and 1.2 g, respectively, and 0.24 g of an antifoaming agent (San Nopco, Nopco 8034) are added, While stirring at 1000 rpm, 240 g of titanium dioxide (manufactured by Teika Co., Ltd., JR-603) was gradually added, and stirring was performed at 3000 rpm for 15 minutes using a disper to obtain a white mill base.
[0080]
403.2 g of this white mill base was placed in a 1000 mL four-necked flask equipped with a stirrer, thermometer, dropping funnel and reflux condenser, and further 50 g of distilled water was added, and the temperature was raised to 70 ° C. under a nitrogen stream. . 0.3 g of ammonium persulfate was added, and 5 g of vinyl monomer of MMA / n-BA / MAA = 49/50/1 (weight ratio) was added dropwise over 10 minutes and left for 60 minutes. Then, after adding 0.4 g of an anionic surfactant (Eoal 20C, solid content 25% by weight, manufactured by Kao Corporation), MMA / n-BA / MAA = 49/50/1 (weight ratio) vinyl unit 95 g of the monomer was added dropwise at 70 ° C. over 4 hours. After completion of dropping, the mixture was further maintained at 70 ° C. for 1 hour, and stirring was continued. Thereafter, the mixture was cooled and adjusted to pH 8.5 with 25 wt% aqueous ammonia to obtain 500 g of an aqueous dispersion (yield 99%, solid content 50 wt%, average particle diameter 305 nm).
[0081]
Synthesis Example 10
Using the components shown in Table 1, an aqueous dispersion was obtained in the same manner as in the above synthesis example.
[0082]
Synthesis Example 11
In a 500 mL steel beaker, 180 g of distilled water, the first nonionic surfactant (manufactured by Asahi Denka Kogyo Co., Ltd., NE-10, cloud point 40 ° C., reactivity), the second nonionic surfactant (Kao Corporation ), Emulgen 840S, solid content 70% by weight, cloud point 100 ° C. or more) are added with 5.0 g and 2.5 g, respectively, wetting agent (manufactured by San Nopco Co., Ltd., Modicol L, nonionic activator, solid content 100). (Weight%) 3.0 g, defoaming agent (manufactured by San Nopco Co., Ltd., Nopco 8034) 0.3 g, and stirring at 1000 rpm, quinacridone red (Daiichi Seika Kogyo Co., Ltd., Chromofine Red 6820) 120 g While gradually adding 200 g, 200 g of glass beads were further added, and the mixture was stirred with a disper at 3000 rpm for 15 minutes.
[0083]
207.2 g of the mixture obtained above was put into a 1000 mL glass four-necked flask equipped with a stirrer, a thermometer, a dropping funnel and a reflux condenser, and further 100 g of distilled water was added, and 70 ° C. under a nitrogen stream. The temperature was raised to. 0.3 g of ammonium persulfate was added, and 5 g of vinyl monomer of MMA / n-BA / MAA = 49/50/1 (weight ratio) was added dropwise over 10 minutes and left for 60 minutes. Then, after adding 0.4 g of an anionic surfactant (Eoal 20C, solid content 25% by weight, manufactured by Kao Corporation), MMA / n-BA / MAA = 49/50/1 (weight ratio) vinyl unit 95 g of the monomer was added dropwise at 70 ° C. over 4 hours. After completion of dropping, the mixture was further maintained at 70 ° C. for 1 hour, and stirring was continued. Thereafter, the mixture was cooled and adjusted to pH 8.5 with 25 wt% aqueous ammonia to obtain 403 g of an aqueous dispersion (yield 99%, solid content 45 wt%, average particle size 283 nm).
[0084]
Comparative Synthesis Example 1
Colloidal silica (manufactured by Nissan Chemical Co., Ltd., Snowtex 50, solid content 50% by weight, average particle size 20 to 20 ml) in a 1000 mL glass four-necked flask equipped with a stirrer, thermometer, reflux condenser, and dropping funnel (30 nm) 200 g, under a nitrogen stream, 25 g of a nonionic surfactant (manufactured by Kao Corporation, Emulgen 840S, solid content 70 wt%, cloud point 100 ° C. or higher) was added with stirring. 2N-H₂SO_FourAfter adjusting the pH to 8 to 8.5, the temperature was raised to 70 ° C. 0.6 g of ammonium persulfate was added, and 5 g of vinyl monomer of MMA / n-BA / MAA = 49/50/1 (weight ratio) was added dropwise for 10 minutes and then dropwise for 60 minutes. Thereafter, 2.0 g of an anionic surfactant (Eoal 20C, solid content 25% by weight, manufactured by Kao Corporation) was added, and vinyl monomer of MMA / n-BA / MAA = 49/50/1 (weight ratio). 95 g was added dropwise over 4 hours. The reaction temperature was maintained at 70 ° C., and after completion of the dropwise addition, the mixture was further maintained at 70 ° C. for 1 hour and stirring was continued. Thereafter, the mixture was cooled and adjusted to pH 8.5 with 25 wt% aqueous ammonia to obtain 400 g of an aqueous dispersion (yield 98%, solid content 50 wt%, average particle diameter 98 nm).
[0085]
Comparative Synthesis Example 2
Colloidal silica (Nissan Chemical Co., Ltd., Snowtex 40, solid content 40% by weight, average particle size 20 to 20 ml) in a 1000 mL glass four-necked flask equipped with a stirrer, thermometer, dropping funnel and reflux condenser. 30Ng) 250g, anionic surfactant (Kao Co., Ltd., Emar 20C, solid content 25% by weight) 16g, distilled water 135g, 2N-H₂SO_FourTo pH 7.5 and stirred. After raising the temperature to 60 ° C. under a nitrogen stream, 10 g of 3-methacryloyloxypropyltrimethoxysilane was added and stirred for 4 hours. Thereafter, 0.5 g of ammonium persulfate and 0.2 g of sodium sulfite were added, and 100 g of vinyl monomer of MMA / n-BA / MAA = 49/50/1 (weight ratio) was added dropwise over 4 hours. The reaction temperature during the dropwise addition was maintained at 65 ° C., and stirring was continued for 1 hour after the completion of the dropwise addition. Thereafter, the mixture was cooled and adjusted to pH 8.5 with 25 wt% aqueous ammonia to obtain 500 g of a composite fine particle dispersion (yield 98%, solid content 40 wt%, average particle diameter 51 nm).
[0086]
Comparative Synthesis Example 3
A 1000 mL glass four-necked flask equipped with a stirrer, thermometer, dropping funnel, reflux condenser, 12 g of anionic surfactant (Eoal 20C, solid weight 25% by weight, manufactured by Kao Corporation), colloidal silica (Nissan) Chemical Co., Ltd., Snowtex 30, solid content 30% by weight) 333 g and distilled water 65 g were added and stirred. After raising the temperature to 60 ° C. under a nitrogen stream, 0.5 g of ammonium persulfate and 0.2 g of sodium bisulfite were added, and MMA / n-BA / MAA / γ-methacryloyloxypropyltrimethoxysilane = 49 / 49.5 / 100 g of 1 / 0.5 (weight ratio) vinyl monomer was added dropwise over 3 hours. The reaction temperature during the dropping was kept in the range of 60 to 70 ° C., and the stirring was continued for 2 hours at the same temperature after the dropping. Thereafter, the mixture was cooled and adjusted to pH 8.5 with 25 wt% aqueous ammonia to obtain 508 g of a composite fine particle dispersion (solid content: 39 wt%, average particle diameter: 76 nm).
[0087]
[Ratio of composite particles, polymer particles and colloidal silica particles]
The aqueous dispersions of Synthesis Examples 1 to 5 and Comparative Synthesis Example 3 were analyzed with a transmission electron microscope.
[0088]
First, the aqueous dispersion of the sample was diluted 10 times with distilled water, and the diluted solution was dried on a mesh Cu200A covered with a carbon film using a spatula. The dried film was observed with a transmission electron microscope TEM (manufactured by JEOL Datum, JEM1220). About 200 particles were observed for one sample under the conditions of an acceleration voltage of 100 kv and a magnification of 20,000, and the number ratio of core-shell type composite particles / polymer single particles / colloidal silica particles was calculated.
[0089]
In the aqueous dispersion obtained in Comparative Synthesis Example 3, the number ratio of core-shell type composite particles / polymer single particles / colloidal silica particles was 12/25/63.
[0090]
[Table 1]

[0091]
From Table 1, the aqueous dispersions of Synthesis Examples 1 and 2 were aqueous dispersions composed of core-shell composite particles with few polymer single particles and colloidal silica particles. The aqueous dispersion of Synthesis Example 3 was composed of composite particles having a core-shell structure and polymer single particles. The aqueous dispersion of Synthesis Example 4 was composed of composite particles having a core-shell structure and colloidal silica particles. The aqueous dispersion of Synthesis Example 5 was composed of a three-component system of core-shell structure composite particles / polymer single particles / colloidal silica particles. From these synthesis examples, in the present invention, the three components can be arbitrarily adjusted by adjusting the synthesis conditions and the nonionic surfactant species.
[0092]
[Storage stability]
The aqueous dispersions of Synthesis Examples 1-2 and 10-11 and Comparative Synthesis Example 1 were stored at room temperature for 3 months, and stored at a temperature of 50 ° C. for 10 days to investigate accelerated storage stability. The results are shown in Table 2.
[0093]
[Table 2]

[0094]
The aqueous dispersions of Synthesis Examples 1-2 and 10-11 showed good storage stability with no increase in viscosity and change in appearance even in storage stability at room temperature and accelerated test at 50 ° C. On the other hand, in the comparative synthesis example, the tendency to hate was recognized because of the free silanol compound, and in particular, in the accelerated test at 50 ° C., a marked increase in viscosity was observed.
[0095]
[Coating composition]
Example 1
In a 500 mL steel beaker, 10.8 g of distilled water, thickener (Asahi Denka Kogyo Co., Ltd., UH420, solid content 6% by weight) 5.0 g, dispersant (Kao Co., Ltd., Demol EP) 4 0.0 g, 1.0 g of wetting agent (Kao Co., Ltd., Emulgen L-40) and 0.8 g of antifoaming agent (San Nopco Co., Nopco 8034) were added and stirred at 1000 rpm while titanium dioxide (Taika) 80 g of (manufactured by Co., Ltd., JR-603) was gradually added, and the mixture was stirred at a rotational speed of 3000 rpm for 15 minutes using a disperser. Thereafter, 200 g of the aqueous dispersion (emulsion) of Synthesis Example 1 was gradually added at 1000 rpm, and 60 g of distilled water was further added and stirred for 5 minutes. Next, 12 g of a film-forming auxiliary (produced by Osaka Organic Chemical Industry Co., Ltd., butyl acetate diuxol) was added and stirring was continued for another 5 minutes to obtain a white paint.
[0096]
Examples 2-5
A coating composition was obtained in the same manner as described above at the ratio shown in Table 3.
[0097]
Example 6
While adding 10.8 g of distilled water and 0.4 g of a defoaming agent (San Nopco Co., Ltd., Nopco 8034) to a 500 mL steel beaker and stirring at 1000 rpm, 200 g of the aqueous dispersion (emulsion) of Synthesis Example 10; 160 g of ordinary acrylic emulsion (G-25, 50% by weight, manufactured by Mizutani Paint Co., Ltd.) was added. Subsequently, 60 g of distilled water and 5.0 g of a thickener (manufactured by Asahi Denka Kogyo Co., Ltd., UH420, solid content: 6% by weight) were added and stirred for about 10 minutes. Further, 12 g of a film-forming auxiliary (produced by Osaka Organic Chemical Industry Co., Ltd., butyl acetate diuxol) was added, and stirring was continued for 5 minutes to obtain a white paint.
[0098]
Example 7
Add 10.8 g of distilled water and 0.4 g of defoaming agent (San Nopco, Nopco 8034) to a 500 mL steel beaker and synthesize with 200 g of the aqueous dispersion (emulsion) of Synthesis Example 10 while stirring at 1000 rpm. 180 g of the aqueous dispersion (emulsion) of Example 6 was added. Subsequently, 60 g of distilled water and 5.0 g of a thickener (Asahi Denka Kogyo Co., Ltd. UH420, solid content 6 wt%) were added and stirred for about 10 minutes. Further, 12 g of a film-forming auxiliary (produced by Osaka Organic Chemical Industry Co., Ltd., butyl acetate diuxol) was added, and stirring was continued to obtain a white paint.
[0099]
Comparative Example 1
Instead of 200 g of the aqueous dispersion of Synthesis Example 1, 200 g of an acrylic emulsion (G-25, solid content 50% by weight, manufactured by Mizutani Paint Co., Ltd.) was used to obtain a white paint. That is, in a 500 mL still beaker, 10.8 g of distilled water, 5.0 g of thickener (6 wt%, UH-420), 4.0 g of dispersant (Demol EP), 1.0 g of wetting agent (Emulgen L40), While adding 0.8 g of foaming agent (San Nopco Co., Ltd., Nopco 8034) and stirring at 1000 rpm with a disper, 80 g of titanium dioxide (JR-603) was gradually added. After the rotation speed was set to 3000 rpm, stirring was continued for 15 minutes. Thereafter, the number of revolutions was set to 1000 rpm, and 200 g of an emulsion (G-25, solid content 50% by weight, manufactured by Mizutani Paint) was added. Further, 150 g of colloidal silica (Adelite AT-50) was added, and 60 g of water and 12 g of a film-forming aid (butyl acetate diuxol) were added and stirred for 10 minutes to obtain a white paint.
[0100]
Comparative Example 2
Instead of 200 g of the aqueous dispersion of Synthesis Example 1, 50 g of an acrylic emulsion (G-25, 50 wt%, manufactured by Mizutani Paint) and 150 g of colloidal silica (Adelite AT-50) were used to obtain a white paint. That is, in a 500 mL steel beaker, distilled water 10.8 g, thickener 5.0 g (6 wt%, UH-420), dispersant 4.0 g (Demol EP), wetting agent 1.0 g (Emulgen L40), While adding 0.8 g of foaming agent (San Nopco Co., Ltd., Nopco 8034) and stirring at 1000 rpm with a disper, 80 g of titanium dioxide (JR-603) was gradually added. After the rotation speed was set to 3000 rpm, stirring was continued for 15 minutes. Thereafter, the number of revolutions was set to 1000 rpm, and 50 g of an emulsion (G-25, solid content 50% by weight, manufactured by Mizutani Paint) and 150 g of colloidal silica (Adelite AT-50) were added. Further, 60 g of water and 12 g of a film-forming auxiliary (butyl acetate diexosol) were added and stirred for 10 minutes to obtain a white paint.
[0101]
Comparative Examples 3-5
A coating composition was obtained in the same manner as described above at the ratio shown in Table 3.
Table 3 shows the compositions of the paints of the above examples and comparative examples.
[0102]
Samples were prepared as follows for the paints of Examples and Comparative Examples.
15 parts by weight of water was added to 100 parts by weight of the paint obtained in Examples and Comparative Examples, and after the sample was prepared, the coating amount was 200 g / m on a 70 × 150 m slate plate.²Then, it was painted with a spray gun and left at room temperature for 7 days to form a coating film.
[0103]
An L-shaped stainless steel test panel for contamination was prepared by painting with a spray gun in the same manner as described above and leaving it at room temperature for 7 days. Note that the L-shaped stainless steel panel has a plate perpendicular to the ground (width 20 cm × height 30 cm) and an angle 120 from the upper end of the plate.^oIt was comprised with the inclination plate (width 20cm x length 70cm) extended diagonally upward, and the edge part of the inclination plate was supportable.
[0104]
And as follows, when film-forming property, tolerance, alkali resistance, boiling resistance, frost damage resistance, accelerated weather resistance, outdoor exposure test, and stain resistance were evaluated, the results shown in Table 3 were obtained. .
[0105]
[Test method and evaluation method]
(1) Storage stability
100 g of the paint was put in a 200 ml container, stored in a hot air drying oven at 50 ° C. for 10 days, the state of the paint was visually observed, and evaluated according to the following criteria.
[0106]
◎: not thickened at all
○: Slightly thickened
Δ: Thickened but does not cause problems in painting
▲: Thickened significantly, not suitable for painting
X: Gelled state
(2) Gloss and film formability
It apply | coated on the glass plate with the doctor blade (4 mil), it was made to dry at room temperature, the coating film was observed with the microscope, and the following reference | standard evaluated. The gloss of the coating is 60^oMeasured as gloss.
[0107]
A: No cracking occurs at temperatures below 5 ° C
○: No cracking
▲: Slightly cracking
X: Remarkably cracked
(3) Adhesion
The cellophane tape peel test was performed with a cross cut width of 2 mm, and the case where the grids were not peeled at all was displayed as 100/100, and the case where all the grids were peeled was displayed as 0/100.
[0108]
(4) Water resistance
It was immersed in water for 20 days, the state of the coating film was visually observed, and evaluated according to the following criteria.
[0109]
A: Remarkably good with no change in coating film
○: Almost no change in coating film, good
△: Level where there is little change in coating film and no problem in practical use
▲: Slightly large change in coating film, causing practical problems
X: The change of the coating film is large and the practicality is poor.
(5) Alkali resistance
The film was immersed in a 30% NaOH aqueous solution for 7 days, the state of the coating film was visually observed, and evaluated according to the same criteria as in (4) above.
[0110]
(6) Frost resistance
The test plate immersed in tap water is subjected to a 50-cycle freezing test in which one cycle is -20 ° C for 16 hours and 20 ° C for 8 hours, and the state of the coating film is visually observed, as in (4) above. Evaluation based on the criteria.
[0111]
(7) Outdoor exposure test
The appearance (gloss, crack, discoloration) of the coating film after 18 months was observed and evaluated according to the same criteria as in (4) above. The gloss gloss retention was also evaluated.
[0112]
(8) Pollution
6 months after coating on the stainless steel plate shown in the figure, it was visually observed by discoloration of the inclined part and the vertical part, and evaluated according to the same criteria as the above (4).
[0113]
(9) Flame resistance
The paint was poured into a mold having a length of 150 mm, a width of 20 mm, and a thickness of 10 mm, and allowed to stand at room temperature for 1 month, and then a test piece having a thickness of 3.0 mm ± 0.5 mm was prepared. This test piece was tested in accordance with JIS K7201, and the flame retardance was evaluated according to the following criteria based on the burning oxygen index value.
[0114]
A: 28 or more
○: 26 or more and less than 28
Δ: 24 or more and less than 26
▲: 20 or more and less than 24
X: Less than 20
[0115]
[Table 3]

[0116]
[Table 4]

[0117]
As shown in Tables 3 and 4, in the paints of Examples 1 to 5, the stain resistance, the outdoor exposure test (weather resistance), the water resistance, etc. are improved by about 1 to 2 ranks compared to Comparative Example 1. ing. Further, as is clear from the comparison between Example 2 and Comparative Example 2, Example 2 can improve the film-forming property, adhesion, resistance, etc., and shows a well-balanced film property. . Furthermore, the gloss of the coating film can be adjusted in a wide range by using an emulsion containing colloidal silica. Furthermore, in Examples 2 and 3 using emulsions with high colloidal silica content (Synthesis Examples 7 and 8), the flame retardancy was relatively evaluated based on the above evaluation criteria. Flame resistance can be imparted without the addition.
[0118]
Moreover, in the coating material of Example 6 using Synthesis Example 10 (using titanium dioxide as fine particles), since titanium dioxide is covered with a polymer, Comparative Example 1 has light resistance, water resistance, alkali resistance, and the like. Compared to other physical properties, it can be improved. Furthermore, the paint of Example 7 using Synthesis Example 10 (using titanium dioxide as the fine particles) and Synthesis Example 6 (using colloidal silica particles as the fine particles) is more pollutant than Example 6. It has been improved.

Claims (16)

Inorganic or organic particles dispersed in an aqueous medium system, the presence of interfacial active agent, an aqueous dispersion obtained by polymerizing a vinyl-monomer, the surfactant is, the polymerization temperature below A first nonionic surfactant having a cloud point at a temperature of 5%, and at least one surfactant selected from a second nonionic surfactant having a cloud point at a temperature above the polymerization temperature and an anionic surfactant. And when the second nonionic surfactant is used, the vinyl monomer is used at a temperature lower than the cloud point of the second nonionic surfactant. It is a dispersion obtained by polymerization, and the vinyl polymer is bonded to the surface of the inorganic or organic particles directly or via a nonionic surfactant , and the inorganic or organic particles are used as a core, and the vinyl polymer is used as a shell. Core Aqueous dispersions composite particles having a shell structure is dispersed in an aqueous medium.   The aqueous dispersion according to claim 1, wherein the inorganic or organic particles are colloidal silica or a pigment. The aqueous dispersion according to claim 1, wherein the first nonionic surfactant is a polyoxyalkylene ether or a derivative thereof. The aqueous dispersion according to claim 1 or 3, wherein the cloud point of the first nonionic surfactant is from 0 to 80 ° C. The aqueous dispersion according to claim 1, 3 or 4, wherein the first nonionic surfactant has at least one ethylenically unsaturated group.   The aqueous dispersion according to claim 1, wherein the vinyl polymer is at least one polymer selected from a (meth) acrylic monomer, an aromatic vinyl monomer, and a vinyl ester monomer. The aqueous dispersion according to claim 1, comprising 3 to 500 parts by weight of inorganic or organic particles and 0.1 to 20 parts by weight of a first nonionic surfactant with respect to 100 parts by weight of the vinyl polymer.   The aqueous dispersion according to claim 1 or 7, wherein 80% by weight or more of the particles are spherical composite particles having a core-shell structure having inorganic or organic particles as a core and vinyl polymer as a shell. The aqueous dispersion according to claim 1, 2, 7, or 8, wherein the composite particles have an average particle size of 10 µm or less.   The aqueous dispersion according to claim 1, wherein the average particle diameter of the inorganic or organic particles is 5 nm to 1 µm, and the average particle diameter of the composite particles is 10 nm to 5 µm. Inorganic or system in which organic particles are dispersed in an aqueous medium in the presence of interfacial active agent, a process for producing an aqueous dispersion by polymerizing a vinyl-monomer, the surfactant, the polymerization At least one surfactant selected from a first nonionic surfactant having a cloud point below the temperature, a second nonionic surfactant having a cloud point above the polymerization temperature, and an anionic surfactant And when the second nonionic surfactant is used, the vinyl monomer is used at a temperature lower than the cloud point of the second nonionic surfactant. A method for producing an aqueous dispersion in which composite particles having a core-shell structure in which an inorganic or organic particle is used as a core and the vinyl polymer is used as a shell are dispersed in an aqueous medium . The aqueous dispersion according to claim 11, wherein the first monomer is heated to a temperature equal to or higher than the cloud point of the first nonionic surfactant, and the vinyl monomer is polymerized by adsorbing the first nonionic surfactant on the surface of the inorganic or organic particles. Body manufacturing method. The method for producing an aqueous dispersion according to claim 11, wherein the polymerization temperature is 60 to 100 ° C. above the cloud point of the first nonionic surfactant. The amount of the first nonionic surfactant used is
(a-1) less than the critical micelle concentration and less than the saturated adsorption amount of inorganic or organic particles,
(a-2) less than the critical micelle concentration, and more than the saturated adsorption amount of inorganic or organic particles,
(b-1) above the critical micelle concentration and less than the saturated adsorption amount of inorganic or organic particles, or
(b-2) The method for producing an aqueous dispersion according to any one of claims 11 to 13 , wherein the vinyl monomer is polymerized at a critical micelle concentration or higher and a saturated adsorption amount of inorganic or organic particles.   A coating composition comprising the aqueous dispersion according to claim 1. Core - ratio of the composite particles and the inorganic or organic particles of shell structure, in terms of solid content, the former / the latter = 100 / 0-50 / 50 claims is composed of an aqueous dispersion (weight ratio) 15 The coating composition as described.