Stock material or miscellaneous articles – Composite – Of silicon containing
Reexamination Certificate
2002-05-01
2004-04-27
Tucker, Philip (Department: 1712)
Stock material or miscellaneous articles
Composite
Of silicon containing
C428S446000, C528S025000, C528S032000, C528S033000, C524S866000, C525S479000
Reexamination Certificate
active
06726997
ABSTRACT:
BACKGROUND OF THE INVENTION
The present invention relates to an aqueous dispersion and a coated product. More particularly, the invention relates to an aqueous dispersion of composite polymer particles obtained by a specified condensation/polymerization process of an organosilane and a radical polymerizable monomer, which is low in the concentration of an alcohol or alcohols having a boiling point of 100° C. or less contained therein, contains a component having ultraviolet absorption action and/or light stabilization action as needed, is excellent in leveling properties and anti-checking properties which have never been obtained by conventional methods, and has extremely excellent weather resistance to be useful as a coating; and a coated product coated with a coating containing the aqueous dispersion.
Previously, coating materials have been used in various fields, and the scope of application thereof keeps on expanding. With the expansion of the scope of application, higher-level performances have increasingly been required for the coating materials. In recent years, coating materials have been desired which are excellent in the balance of performances such as adhesion, chemical resistance, moisture resistance, weather resistance, (hot) water resistance and stain resistance, and can form coating films high in hardness.
As coating materials partly satisfying such requirements, there are proposed a composition comprising a partial condensation product of an organosilane, a dispersion of colloidal silica and a silicone-modified acrylic resin (Japanese Patent Laid-open Publication (Sho) 60-135465) and a composition comprising a condensation product of an organosilane, a chelate compound of a zirconium alkoxide and a hydrolytic silyl group-containing vinyl resin (Japanese Patent Laid-open Publication (Sho) 64-1769).
However, all these coating materials are of the solvent type, and the switchover to aqueous coating materials has been promoted, with their use enlarged, because of strong demands for desolvation from the viewpoints of low pollution, resource saving, safety and sanitation in recent years. With the switchover to the aqueous coating materials, higher-level performances have increasingly been required for the aqueous coating materials.
In such a situation, the developments of reactive resin emulsions as the aqueous coating materials which can be expected to improve performances such as water resistance and chemical resistance have intensively been studied, and as one of them, a hydrolytic silyl group-containing resin emulsion has been proposed. As an example thereof, Japanese Patent Laid-open Publication (Hei) 5-25354 discloses a reactive resin emulsion comprising a hydrolytic silyl group- and amineimido group-containing vinyl polymer, and Japanese Patent Laid-open Publication (Hei) 5-331408 discloses an aqueous coating composition comprising an aqueous dispersion of an alkoxysilyl group-containing vinyl polymer and an aqueous dispersion of a tin compound.
However, these hydrolytic silyl group-containing resin emulsions are poor in storage stability, and have a problem in respect to practicability, because particularly when stored for a long period of time, the emulsions gel, or coating films obtained from the emulsions after long-term storage are different from coating films obtained from the emulsions immediately after production in performances, resulting in failure to ensure stable quality. Even when the emulsions are relatively good in storage stability, the balance of performances including adhesion, weather resistance and stain resistance can not be satisfied.
Further, Japanese Patent Laid-open Publication (Hei) 11-255846 proposes a silicone resin-containing emulsion composition obtained by emulsion polymerization of a solution containing a silanol group-containing silicone resin and a radical polymerizable monomer. However, this process precipitates a large amount of condensation product during polymerization, or reduces polymerization ability, so that it is difficult to industrially utilize the process.
On the other hand, of polymer components which have hitherto been used in the coating materials, (meth)acrylic polymers have been widely used in the coating materials as aqueous dispersions, because of their excellent transparency and film forming properties. Further, polysiloxanes have excellent weather resistance, water repellency and adhesion to inorganic base materials. Aiming at the synergetic effect of excellent performances of these (meth)acrylic polymers and polysiloxanes, for example, Japanese Patent Laid-open Publication (Hei) 3-45628 and Japanese Patent Laid-open Publication (Hei) 4-261454 propose that both the polymer components are compounded, and used in coating materials. However, although the composite materials of these (meth)acrylic polymers and polysiloxanes have good weather resistance, they can not be satisfied in terms of adhesion to organic base materials and weather resistance to stripe-like stains caused by rain fall. Further, Japanese Patent Laid-open Publication (Hei) 4-214747 proposes a self-crosslinking polymer latex composition comprising an organopolysiloxane-containing polymer latex obtained by copolymerizing a carbonyl group-containing monomer with another monomer in the presence of hydrolytic silane, and a multifunctional hydrazine derivative. Still further, Japanese Patent Laid-open Publication 2000-53919 proposes a silicone-containing aqueous coating agent composition obtained by polymerizing an aqueous emulsion containing a polyalkoxypolysiloxane, an unsaturated monomer and an emulsifier. However, these compositions are also difficult to retain the weather resistance and stain resistance of coating films for a long period of time.
Furthermore, Japanese Patent Laid-open Publication (Hei) 9-3394 proposes a composition for a coating which can retain luster retaining properties and weather resistance for a long period of time, the composition containing a copolymer obtained by polymerization, for example, emulsion polymerization, of a monomer mixture containing a benzotriazole-based ultraviolet absorbing monomer, a cycloalkyl group-containing unsaturated monomer and a hydroxyl group-containing monomer. In addition, Japanese Patent Laid-open Publication (Hei) 10-120724 proposes a highly durable emulsion which is an acrylic emulsion obtained by emulsion polymerization of an acrylic monomer in an aqueous medium in the presence of an ultraviolet absorbing agent and/or a light stabilizer, and by silicone modification during or after the emulsion polymerization.
However, of these, the former can not be satisfied as a coating in various characteristics, because the polymer contained therein has no polysiloxane component. The latter has a limitation on the amount of the polysiloxane component substantially compounded/integrated, from the restrictions of polymerization stability and storage stability. Further, the silicone modification is carried out after the emulsion polymerization of the acrylic monomer has substantially considerably proceeded. Accordingly, the polysiloxane component and the acrylic monomer are not sufficiently compounded/integrated, which causes a problem in storage stability. Furthermore, the latter is not necessarily sufficient as a coating in various characteristics.
As described above, the aqueous coating agents have previously been used in various fields against a background of the environmental problems, and the scope of application thereof keeps on expanding. With the expansion of the scope of application, higher-level performances have increasingly been required for the coating agents.
In particular, coating agents have recently been desired which have such a high level of weather resistance that recoating is unnecessary for 10 to 30 years when they are used as coatings for outer walls.
As means for satisfying these requirements, the polyorganosiloxane composite polymer particles disclosed in Japanese Patent Laid-open Publication (Hei) 3-45628, which are obtained by compounding a polyorganosiloxane and an orga
Ishizuki Kenji
Shida Hirotaka
Tamori Kouji
Feely Michael
JSR Corporation
Oblon & Spivak, McClelland, Maier & Neustadt P.C.
Tucker Philip
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