Patent ID: 7217749

Claim:
A process for infusing a synthetic resinous substrate with an alkali metal nitrite, comprising the steps of: depositing alkali metal nitrite crystals in a pressure vessel and pressurizing the vessel with carbon dioxide until supercritical conditions are attained, said alkali metal nitrite being substantially soluble in said supercritical carbon dioxide and the amount of said alkali metal nitrite crystals being from about 0.1% to about 15% by weight based upon the total weight of said alkali metal nitrite crystals and said carbon dioxide; contacting the synthetic resinous substrate with the solublized alkali metal nitrite supercritical solution for a time sufficient to transfer at least a portion of the alkali metal nitrite into the synthetic resinous substrate while maintaining the carbon dioxide under supercritical conditions; and, decreasing pressure or temperature, or both, on the synthetic resinous substrate sufficiently to evolve carbon dioxide so that alkali metal nitrite crystals are infused in said substrate in an amount from about 0.1% to about 15% by weight based upon the total weight of said nitrite crystals and said substrate.