Stock material or miscellaneous articles – Composite – Of silicon containing
Reexamination Certificate
2001-04-13
2004-06-29
Robertson, Jeffrey B. (Department: 1712)
Stock material or miscellaneous articles
Composite
Of silicon containing
C106S286400, C106S287100, C524S379000, C524S430000, C524S439000, C524S588000
Reexamination Certificate
active
06756124
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates to a coating composition excellent in dispersion stability of a photocatalyst, excellent in storage stability even when the composition has a high concentration, giving a coating layer excellent in durability and adhesion, and having a photocatalytic function, a method for producing the same, a cured product and a coating film.
BACKGROUND OF THE INVENTION
In recent years, compositions for coating have been desired which can form coating layers excellent in resistance to weather, resistance to stains and resistance to chemicals, and moreover high in hardness. Furthers coating compositions having the increased versatility will be desired in future. So far, compositions comprised of silyl group-containing vinyl resins and organosilane compounds are described in Japanese Patent Laid-open Publication (Hei) 01-69673 and Japanese Patent Laid-open Publication (Hei) 01-69674. However, they are all limited in substrates. Such compounds are further described in Japanese Patent Laid-open Publication (Hei) 04-108172, Japanese Patent Laid-open Publication (Hei) 04-117473 and so forth. However, detailed coating specifications are not described therein, although subject substrates cover a wide range.
On the other hand, organosilane coating materials have technically been developed for use as maintenance-free coating materials excellent in resistance to weather (sunlight) and resistance to stains. The performance required for such organosilane coating materials increasingly become severe. In recent years, coating materials have been desired which can form coating layers excellent in coating appearance, adhesion, resistance to weather, heat, alkalis, organic chemicals, moisture and (hot) water, insulation durability, abrasion resistance and resistance to stains, and high in hardness
In particular, for improving resistance to stains, it is known that hydrophilization of surfaces of coating layers is suitable. For example, methods of adding hydrophilic materials or water-soluble materials to the coating composition are proposed. According to such methods, however, the hydrophilic materials or water-soluble materials are gradually deteriorated by light, or washed away with water, which makes it difficult to maintain the hydrophilicity of the surfaces of the coating layers at a sufficient level for a long period of time.
In recent years, many compositions for coating in which photocatalytic components are Compounded have been proposed. For example, a method for forming an inorganic coating layer (Japanese Patent Laid-open Publication (Hei) 8-259891) is known in which 20 to 200 parts by weight of tetraalkoxysilane, 100 parts by weight of trialkoxysilane and 0 to 60 parts by weight of dialkoxysilane are used as raw materials, and a coating layer obtained from a mixed solution of an inorganic paint and a powder having a photocatalytic function is treated with an acid or an alkali, the inorganic paint being prepared from the raw materials and having a polystyrene-converted weight-average molecular weight of 900 or more, as well as a titanium oxide coating layer forming composition for a photocatalyst comprising titanium oxide, a hydrolyzate of a hydrolytic silicon compound (an alkyl silicate or a silicon halide) and a solvent (water or an alcohol) (Japanese Patent Laid-open Publication (Hei) 9-164334), and a surface treatment composition for imparting antibacterial and mildewproofing properties comprising a silicon compound having at least two alkoxyl groups, a titanium compound or zirconium compound having at least two alkoxyl groups and a hydrophilic inorganic powder such as alkoxysilane- and/or polysiloxane-treated titanium oxide having a guanidyl group (Japanese Patent Laid-open Publication (Hei) 8-176527).
However, these compositions and mixed solution for coating layer formation substantially aim at antibacterial and mildewproofing properties, deodorization and decomposition of injurious matter due to the photocatalytic components or alkoxysilane- and/or polysiloxane components having a guanidyl group. However, accompanying with above functions, coating layer performances required for organosilane coating materials, including hardness, adhesion, and resistance to alkalis, organic chemicals, weather and stains, are not studied overall.
On the other hand, as coating compositions satisfying the required performance to some degree, there are proposed a composition in which a partial condensate of organosilane, a dispersion of colloidal silica and a silicone-modified acrylic resin are compounded (Japanese Patent Laid-open Publication (Sho) 60-135465), a composition in which a condensate of organosilane, a chelate compound of zirconium alkoxide and a hydrolytic silyl group-containing vinyl resin are compounded (Japanese Patent Laid-open Publication (Sho) 64-1769), and a compound in which a condensate of organosilane, a colloidal alumina and a hydrolytic silyl group-containing vinyl resin are compounded (U.S. Pat. No. 4,904,721)
However, coating layers obtained from the compositions disclosed in Japanese Patent Laid-open Publication (Sho) 60-135465 and U.S. Pat. No. 4,904,721 described above have the disadvantage that their luster is decreased by long-term irradiation of ultraviolet rays. Also, the composition disclosed in Japanese Patent Laid-open Publication (Sho) 64-1769 described above is insufficient in storage stability, and has the problem that an increase in solid concentration is liable to cause gelation within a short period of time.
Further, the present inventors have already proposed a coating composition containing a hydrolyzate and/or a partial condensate of organosilane, a vinyl resin having a hydrolytic silyl group and/or a silyl group having a silicon atom bonded to a hydroxyl group, a metallic chelate compound, and a &bgr;-diketone and/or a &bgr;-keto ester (Japanese Patent Laid-open Publication (Hei) 5-345877). Although the composition is excellent in the balance of the above-mentioned coating layer performances required for any organosilane coating material, it is also required that these performances are further improved.
Furthermore, in Japanese Patent Laid-open Publication (Hei) 9-227161, a self-cleaning film provided with a surface layer containing substantially transparent photocatalytic oxide particles is disclosed. However, the film is deteriorated in quality by a photocatalytic function for itself, thus a problem with regard to long-term durability is sometimes raised. Furthermore, in Patent Laid-open Publication (Hei) 9-313687, a photocatalytic sheet provided with a photocatalytic layer on its surface and coated with an adhesive agent on the back thereof, thereby attaching it to another device or member to offer a photocatalytic function is proposed. However, the sheet is similarly deteriorated in quality by a photocatalytic function for itself, bringing a problem with regard to long-term durability
On the other hand, in the case that a photocatalyst (titanium dioxide) is used in the coating composition as an aqueous dispersion, the strong acidic aqueous dispersion is easily dispersible in an alcohol relatively high in hydrophobicity (for example, i-propyl alcohol or i-butyl alcohol), because of its excellent dispersion stability. However, the strong acidic aqueous dispersion brings problems such as corrosiveness to machines used in the production or coating of the resultant composition and the environmental safety. On the contrary, when aqueous titanium dioxide dispersion having a pH of 3 to 9 is used considering these problems, the problem of poor dispersion stability in the above-mentioned hydrophobic alcohol is encountered. When a solvent which can stabilize aqueous titanium dioxide dispersion having a pH of 3 to 9, for example, diethylene glycol monoethyl ether, is used for solving this problem, a cissing phenomenon of the composition is sometimes observed on an undercoat layer such as intermediate layer or a substrate, because this solvent has high surface tension.
SUMMARY OF THE INVENTION
The present invention has
Hashiguchi Yuichi
Honda Miwa
Kanamori Tarou
Kawahara Kouji
LandOfFree
Coating composition, method for producing the same, cured... does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Coating composition, method for producing the same, cured..., we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Coating composition, method for producing the same, cured... will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-3365574