METHOD FOR IMPROVING FIRE RETARDANCY OF CURED SILICONE RUBBER

PROBLEM TO BE SOLVED: To provide a method for imparting stable fire retardancy to a heat-cured silicone rubber obtained from a liquid addition-curable silicone rubber composition.SOLUTION: A liquid addition-curable silicone rubber composition includes: organopolysiloxane (A) having 2 or more silicon atom-bonded alkenyl groups in a molecule; an organopolysiloxane resin (B) having a three-dimensional network structure which contains an RSiOunit (R represents a monovalent hydrocarbon group) and a SiOunit in a molar ratio [RSiO/SiO] of 0.5 to 1.5, with an alkenyl group content of 1×10to 5×10mol/g; organohydrogenpolysiloxane (C) which contains 2 or more silicon atom-bonded hydrogen atoms in a molecule; an inorganic filler (D); iron oxide fine particles (E); and an addition reaction catalyst (F). A method for improving fire retardancy of a silicone rubber formed by curing the composition includes controlling the heat loss of the component (C) after heating at 105°C for 3 hours to a level of 2.0 mass% or less.