| 摘要 |
The specification describes and claims a method of producing a foamed mass having a density of less than 150kg/m<3> adherent to surfaces of a cavity which comprises inserting into the cavity a foamable composition formed by mixing impinging jets of two or more parts of a foamable silicone composition capable of curing at 20 DEG C within 2 minutes to provide a foamed mass having a density of less than 150kg/m<3>. The Compositions comprises (a) one or more polysiloxanes having not less than three alkylhydrogensiloxane units per molecule, (b) one or more polysiloxanes having not less than two silicon-bonded hydroxyl groups per molecule, (c) one or more compounds having carbon-bonded hydroxyl groups present in a proportion to provide from 0 to 2% by weight of the composition, (d) a polyorganosiloxane comprising <CHEM> R3SiO1/2 and SiO4/2 units and silicon-bonded hydroxyl groups wherein each R represents a monovalent hydrocarbon group containing from 1 to 20 carbon atoms, m is an integer having an average value from 1 to 20, n has the value 1 or 2, p has the value 1, 2 or 3 and (e) a platinum catalyst for promoting reaction between the ingredients. The composition is provided as said two or more parts, each of the parts having a similar viscosity at 25 DEG C one to the other, which is less than 15000 mm<2>/s and the components being present in the mixed composition in proportions such that the ratio of silicon-bonded hydrogen atoms of said one or more polysiloxanes having not less than three alkylhydrogen siloxane units per molecule to silicon-bonded hydroxyl groups and carbon-bonded hydroxyl groups of the other components of the composition lies in the range 1:1 to 6:1. The method enables rapid production of foamed in situ masses having sound deadening and fire resistant properties, suitable for use for example in automobiles. |
