compounds, more particularly brominated compounds, and compounds based on magnesium hydroxide. [0022] Examples of resilience modifiers that may be mentioned include elastomers, optionally grafted with maleic anhydride, such as EPDMs, EPRs and SEBSs, silicone elastomers and nitrile rubbers. [0023] These examples have no limiting nature. [0024] The proportions of each of the three components used to