| 摘要 |
A process for the production of an expandable silicone resin includes reacting a substantial amount of the silanol (SiOH) groups present in the resin to form siloxane bonds and water, and heating the resin to a temperature above the resin's melting point, at which chemical reaction (condensation) of the silanol groups occur. The reaction increases the molecular weight of the resin and decreases the amount of water that must be removed during a subsequent foaming step, thereby controlling the rate and extent of foaming which can occur. The resin is solidified, pulverized and size-reduced to a powder form. The resin powder is blended with a minor amount of a particulate inert filler which is coated with a silicone resin curing catalyst and also with a minor amount of blowing agent (powder). The dry powder blend is then thermally fused for a closely-controlled, short duration, time at a temperature near the lower end of the blowing agent's gas-generating temperature range. The fused mass is ground to a powdered form to produce an expandable resin.
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