Method for producing aqueous silicone resin emulsion for preparing coating composition

A method for preparing an aqueous coating composition comprising a silicone resin emulsion, comprising the following steps:

• an emulsification step of subjecting a mixture of a silicone resin (A) and an organic solvent (B) and a mixture of an emulsifier (C) and an aqueous medium to a mechanical emulsification treatment or subjecting a mixture of a silicone resin (A), an organic solvent (B) and an emulsifier (C) and an aqueous medium to a mechanical emulsification treatment, thereby obtaining an emulsified mixture,
• a desolventization step of at least partially removing the organic solvent (B) from the resulting emulsified mixture, thereby obtaining a silicone resin emulsion, and
• a step of preparing an aqueous coating composition comprising the resulting silicone resin emulsion,
• wherein the silicone resin (A) comprises
• a branched organopolysiloxane (A1) having a weight average molecular weight within a range of 5,000 to 100,000, and
• a linear organopolysiloxane (A2) having a weight average molecular weight within a range of 1,000 to 30,000,
• a mass ratio of the branched organopolysiloxane (A1) and the linear organopolysiloxane (A2) contained in the aqueous coating composition is within a range of (A1):(A2)=98:2 to 40:60,
• the organic solvent (B) is an organic solvent which is miscible with the silicone resin (A) in any ratio and has a solubility in water of 1 g/100 g-H2O or less or a mixture thereof, provided that at least one species of the organic solvent has an azeotropic point with water, and
• a mass ratio (A):(B) of the silicone resin (A) and the organic solvent (B) in the mixture before the mechanical emulsification treatment comprising the silicone resin (A) and the organic solvent (B) satisfies the relationship of (A):(B)=1:2 to 1:0.2, and amass ratio (A):(B) of the silicone resin (A) and the organic solvent (B) contained in the emulsified mixture satisfies the relationship of (A):(B)=1:2 to 1:0.2.

A method for preparing an aqueous coating composition comprising a silicone resin emulsion, comprising the following steps:

• an emulsification step of subjecting a mixture of a silicone resin (A) and an organic solvent (B) and a mixture of an emulsifier (C) and an aqueous medium to a mechanical emulsification treatment or subjecting a mixture of a silicone resin (A), an organic solvent (B) and an emulsifier (C) and an aqueous medium to a mechanical emulsification treatment, thereby obtaining an emulsified mixture,
• a desolventization step of at least partially removing the organic solvent (B) from the resulting emulsified mixture, thereby obtaining a silicone resin emulsion, and
• a step of mixing the resulting silicone resin emulsion and an emulsion prepared in advance and comprising a linear organopolysiloxane (A2) having a weight average molecular weight within a range of 1,000 to 30,000, thereby preparing an aqueous coating composition,
• wherein the silicone resin (A) comprises a branched organopolysiloxane (A1) having a weight average molecular weight within a range of 5,000 to 100,000, and
• a mass ratio of the branched organopolysiloxane (A1) and the linear organopolysiloxane (A2) contained in the aqueous coating composition is within a range of (A1):(A2)=98:2 to 40:60,
• the organic solvent (B) is an organic solvent which is miscible with the silicone resin (A) in any ratio and has a solubility in water of 1 g/100 g-H2O or less or a mixture thereof, provided that at least one species of the organic solvent has an azeotropic point with water,
• a mass ratio (A):(B) of the silicone resin (A) and the organic solvent (B) in the mixture before the mechanical emulsification treatment comprising the silicone resin (A) and the organic solvent (B) satisfies the relationship of (A):(B)=1:2 to 1:0.2, and a mass ratio (A):(B) of the silicone resin (A) and the organic solvent (B) contained in the emulsified mixture satisfies the relationship of (A):(B)=1:2 to 1:0.2.

A method for preparing an aqueous clear coating composition comprising a silicone resin emulsion, comprising the following steps:

• an emulsification step of subjecting a mixture of a silicone resin (A) and an organic solvent (B) and a mixture of an emulsifier (C) and an aqueous medium to a mechanical emulsification treatment or subjecting a mixture of a silicone resin (A), an organic solvent (B) and an emulsifier (C) and an aqueous medium to a mechanical emulsification treatment, thereby obtaining an emulsified mixture,
• a desolventization step of at least partially removing the organic solvent (B) from the resulting emulsified mixture, thereby obtaining a silicone resin emulsion, and
• a step of mixing the resulting silicone resin emulsion and an inorganic oxide fine particle (D), thereby preparing an aqueous clear coating composition,
• wherein the silicone resin (A) comprises a branched organopolysiloxane (A1) having a weight average molecular weight within a range of 5,000 to 100,000,
• the organic solvent (B) is an organic solvent which is miscible with the silicone resin (A) in any ratio and has a solubility in water of 1 g/100 g-H2O or less or a mixture thereof, provided that at least one species of the organic solvent has an azeotropic point with water,
• a mass ratio (A):(B) of the silicone resin (A) and the organic solvent (B) in the mixture before the mechanical emulsification treatment comprising the silicone resin (A) and the organic solvent (B) satisfies the relationship of (A):(B)=1:2 to 1:0.2, and a mass ratio (A):(B) of the silicone resin (A) and the organic solvent (B) contained in the emulsified mixture satisfies the relationship of (A):(B)=1:2 to 1:0.2,
• the inorganic oxide fine particle (D) has an average particle diameter within a range of 20 to 300 nm.

A method for preparing an aqueous clear coating composition comprising a silicone resin emulsion, comprising the following steps:

• an emulsification step of subjecting a mixture of a silicone resin (A) and an organic solvent (B) and a mixture of an emulsifier (C) and an aqueous medium to a mechanical emulsification treatment or subjecting a mixture of a silicone resin (A), an organic solvent (B) and an emulsifier (C) and an aqueous medium to a mechanical emulsification treatment, thereby obtaining an emulsified mixture,
• a desolventization step of at least partially removing the organic solvent (B) from the resulting emulsified mixture, thereby obtaining a silicone resin emulsion, and
• a step of mixing the resulting silicone resin emulsion, an inorganic oxide fine particle (D) and an emulsion prepared in advance and comprising a linear organopolysiloxane (A2) having a weight average molecular weight within a range of 1,000 to 30,000, thereby preparing an aqueous clear coating composition,
• wherein the silicone resin (A) comprises a branched organopolysiloxane (A1) having a weight average molecular weight within a range of 5,000 to 100,000, and
• a mass ratio of the branched organopolysiloxane (A1) and the linear organopolysiloxane (A2) contained in the aqueous clear coating composition is within a range of (A1):(A2)=98:2 to 40:60,
• the organic solvent (B) is an organic solvent which is miscible with the silicone resin (A) in any ratio and has a solubility in water of 1 g/100 g-H2O or less or a mixture thereof, provided that at least one species of the organic solvent has an azeotropic point with water,
• a mass ratio (A):(B) of the silicone resin (A) and the organic solvent (B) in the mixture before the mechanical emulsification treatment comprising the silicone resin (A) and the organic solvent (B) satisfies the relationship of (A):(B)=1:2 to 1:0.2, and a mass ratio (A):(B) of the silicone resin (A) and the organic solvent (B) contained in the emulsified mixture satisfies the relationship of (A):(B)=1:2 to 1:0.2,
• the inorganic oxide fine particle (D) has an average particle diameter within a range of 20 to 300 nm.