| abstract |
The invention relates to a potting paste composition for honeycomb reinforcement having improved fire retardancy characteristics. The potting paste composition comprises (a) a curable polymer; (b) a curing agent for the curable polymer; (c) a fire retardant comprising an ammonium polyphosphate in combination with an ingredient selected from the group consisting of metal hydroxides, expandable graphites, liquid phosphate esters, phosphorous organic compounds or salts thereof, and zeolites; and(d) a filler selected from the group consisting of polymeric microspheres, hollow glass microspheres, and thixotropic fillers; wherein the potting paste has an uncured density determined by the method according to EN ISO 1183 of not more than 0.7100 g/cm3, preferably of at most 0.680 g/cm3, more preferably of at most 0.673 g/cm3, still more preferably of at most 0.660 g/cm3, even more preferably of at most 0.658 g/cm3, yet more preferably of at most 0.653 g/cm3 and in particular of at most 0.620 g/cm3; and wherein the total content of the fire retardant is at least 5.0 wt.-%, preferably at least 10 wt.-%, more preferably at least 15 wt.-%, relative to the total weight of the potting paste composition. |