| 摘要 |
<p>A silicone composition comprises a continuous phase of a polar organic liquid having dispersed therein particles of a silicone antifoam in intimate contact with and surrounded by an encapsulant. The encapsulant is solid at 25 ° C and is sparingly soluble in the polar organic liquid at 25 °C but is substantially dissolved in the polar organic liquid at an elevated temperature in the range 40-100 °C. The encapsulated silicone antifoam composition can be produced by (i) dispersing a polyorganosiloxane fluid, a solid organic material and a hydrophobic silicaceous material in a polar organic liquid with shear so that the average silicone particle size is less than 0.5mm., the temperature of the resulting dispersion being sufficiently high that the said organic material is dissolved in the composition; and (ii) cooling the dispersion to deposit the organic material onto the interface of the silicone particles while agitating sufficiently to maintain the silicone particle size below 0.5mm.</p> |
