Patent ID: 7713581

Claim:
A method of impregnating a carrier matrix with at least one impregnating material comprising at least one solid or liquid compound using compressed gas, said compressed gas having a critical temperature and a critical pressure, comprising: contacting said at least one impregnating material and said carrier matrix with a compressed gas at a gas density of from 0.15 to 1.3 kg/l under at least two unsymmetrical pressure pulsations in such a manner that, per individual pulsation of a duration of from 5 s to 60 min, the respective time period to achieve the pressure maximum is greater than the time period for pressure reduction to the pressure minimum, wherein said carrier matrix is not soluble in said compressed gas and wherein the solubility of said impregnating material in said compressed gas is higher in the pressure maximum than in the pressure minimum, wherein the time period to achieve the pressure maximum is from 5 to 30 times greater than the time period for pressure reduction to the pressure minimum.