Patent ID: 12215227

EXAMPLES

The present invention is described below in detail based on examples and comparative examples. In the examples, the viscosity is measured at 25° C. The term “parts” in the blended amounts refers to parts by mass, and the term “%” indicating the amount refers to the mass %. Note that in the formula, Me represents a methyl group, and Et represents an ethyl group.

The average particle size of the emulsion particles was measured using a submicron particle analyzer (Coulter Electronics Inc. COULTER MODEL N4 MD) using a dynamic light scattering method at 25° C., or calculated by single dispersion mode analysis.

The viscosity of the emulsion composition was measured at 25° C. using a Wells-Brookfield Cone/Plate Viscometer provided with a 20 mm diameter 2° tapered cone, at a shear rate of 1s-1 measured (ASTM D4287).

Evaluation of Cured Film

The oil-in-water silicone emulsion composition (coating film-forming composition) of each example was applied by gravure roller coating to a coating surface of a woven nylon airbag fabric, heat cured at 140° C., and evaluated for the following items.Uniformity: The uniformity was visually evaluated for a coating film formed when the coating film composition was applied at a rate of 20 g/m2.Friction reduction: As an indicator of initial wear resistance, the coefficient of kinetic friction was measured when the coating film composition was applied at a rate of 25 g/m2.Friction reduction after scribing: Scribing was performed by a finger 10 times, and then evaluated by finger touch.

Example 1

92.5 parts of (a) polydimethylsiloxane blocked with a hydroxydimethylsiloxy group at both ends of a molecular chain and having a viscosity of 2400 mPa-s and 7.5 parts of (b) polysiloxane containing an aminoxy group expressed by Formula (1):

Et2NO(Me2SiO)7NEt2 were uniformly blended in a pre-blended dispersion containing 7.5 parts of (C2) polyoxyethylene-polyoxypropylene copolymer type nonionic emulsifier (Product name: Pluronic (registered trademark) F108 manufactured by Adeka) and 12.5 parts of (C1) a 40% aqueous solution of sodium alkane sulfonate, and emulsified in an emulsifier.

86 parts of (D) water, 44.0 parts of (B-1) colloidal silica (Product name: Snowtex 30 produced by Nissan Chemical, active ingredient 30%, pH 10, colloidal silica surface stabilized with sodium), and 1.25 parts of (G) diethylamine were added to the emulsion that was obtained, and then uniformly blended. Furthermore, 2.5 parts of (F) methyltriethoxysilane was added, blended uniformly, and allowed to stand at room temperature for 2 weeks, then 125 parts of (B-2) colloidal silica (Nissan Chemical product name: Snowtex 30, active ingredient 30%, pH 10, surface stabilized by sodium) was added and mixed uniformly to produce an oil-in-water type silicone emulsion (No. 1). The total amount of silica particles was 50.7 parts.

The viscosity of the reacted organopolysiloxane (A) obtained by emulsion polymerization was measured by the following procedure. 92.5 parts of (a) polydimethylsiloxane blocked with a hydroxydimethylsiloxy group at both ends of a molecular chain and having a viscosity of 2400 mPa-s and 7.5 parts of (b) polysiloxane containing an aminoxy group expressed by Formula (1): Et2NO(Me2SiO)7NEt2 were uniformly blended in a pre-blended dispersion containing 7.5 parts of (C2) polyoxyethylene-polyoxypropylene copolymer type nonionic emulsifier (Product name: Pluronic (registered trademark) F108 manufactured by Adeka) and 12.5 parts of (C1), a 40% aqueous solution of sodium alkane sulfonate, and emulsified in an emulsifier. After allowing to sit for one week, 10 g of isopropyl alcohol was added to 10 g of the prepared emulsion while stirring, and only the precipitated dimethylsiloxane was dried at 105° C. for 3 hours, and measured using a Brookfield type viscometer. The viscosity at 25° C. was 1,800,000 mPa·s.

12 parts of the silicone emulsion (No. 1) obtained above was uniformly blended with a dispersion obtained by adding 73 parts of (E) 1.5% aqueous solution of an anionic polymer composite purified bentonite (product name: Venger W100U: Hojun Co., Ltd.) and 15 parts of talc powder, to obtain the oil-in-water silicone emulsion composition of the present invention (coating film composition).

When the resulting oil-in-water silicone emulsion was allowed to sit at 25° C., no separation was observed even after 6 months, and the dispersion state was stable. In addition, when evaluated by the method described above, a cured film could be formed. The results are shown in Table 1.

Example 2

A silicone emulsion (No. 2) and a coating film composition were prepared by the same method as Example 1, except that the total amount of silica particles was changed to 65.7 parts, and an evaluation was carried out by the same method as Example 1. The results are shown in Table 1.

Example 3

A silicone emulsion (No. 3) and a coating film composition were prepared by the same method as Example 1, except that the total amount of silica particles was changed to 73.2 parts, and an evaluation was carried out by the same method as Example 1. The results are shown in Table 1.

Comparative Example 1

A silicone emulsion (No. C1) and a coating film composition were prepared by the same method as Example 1, except that total amount of silica particles was changed to 24.75 parts, and the evaluation was carried out by the same method as Example 1. The results are shown in Table 1.

Comparative Example 2

A silicone emulsion (No. C2) and a coating film composition were prepared by the same method as Example 1, except that total amount of silica particles was changed to 35.7 parts, and the evaluation was carried out by the same method as Example 1.

TABLE 1Compar-Compar-ExampleExampleExampleativeative123Example 1Example 2Viscosity3710036400487002130035400(mPa · s)UniformityFavorableFavorableFavorableRepellentRepellentKinetic0.350.360.350.510.38coefficientof frictionAbrasionSmoothSmoothSmoothTackyTackyresistanceandandandafterslipperyslipperyslipperyscrubbing

SUMMARY

The oil-in-water type silicone emulsion composition (=coating film composition) of Examples 1 to 3 provided a coating film having a solid content of the colloidal silica that was within the scope of the present invention, and thus a coating film having excellent uniformity was formed, and a smooth cured film could be formed on a substrate. On the other hand, in Comparative Examples 1 and 2, the uniformity of the coating film was insufficient and the friction reduction was inferior compared to the examples, and a coating film with reduced surface tackiness (tack) could not be achieved.

INDUSTRIAL APPLICABILITY

The oil-in-water type silicone emulsion composition of the present invention has favorable storage stability even though it contains colloidal silica, and when water content is removed after application or impregnation on a substrate, a cured film with rubber-like elasticity, or in other words, excellent strength is formed. Therefore the composition is useful in water-based paints and inks, as a paper coating agent for thermal paper and inkjet paper, a mold release agent for molds and rubber, a resin coating agent for automotive weather stripping, gaskets and rubber hoses, a fiber treatment agent for clothing and airbags, as well as a release agent, cosmetic, construction material, and the like.