US Patent 7258868 Volatile releasing substrates and methods for preparing them

Substrates are provided for use in a heating and/or blowing device that dispenses volatile material. The substrates are a porous medium (such as porous ceramic) having their interior pores coated by a polymeric material (such as a polysiloxane). The substrate is impregnated with a volatile such as pyrethrum. The substrate is less susceptible to clogging. Also disclosed are methods of making those substrates in which the polymeric material is wicked into the substrate with a volatile solvent.