Impregnated porous granules with slow release pore membranes and process therefor
AssigneeStauffer Chemical Company
InventorsAlice U. Hahn, Richard H. Rider, Herbert B. Scher, Garrard L. Hargrove
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Abstract
Open-ended pores of a porous granule are filled with a liquid material which is at least partially immiscible with water, and sealed with a porous polyurea membrane which limits the release rate of the material into the surrounding medium. The membrane is formed by (a) applying to the bare granule an organic solution comprising the liquid material and an organic polyisocyanate, followed by (b) applying to the granule an aqueous solution comprising water and a catalytic amount of a catalyst selected from the group consisting of a basic organic tertiary amine and an alkyl tin carboxylate.
Claims28
A method for impregnating a porous granule with a material which is at least partially immiscible with water and sealing said material within the pores of said granule by covering the openings of said pores with a porous membrane to effect a slow rate of release of said material from said granule, which comprises
- (a) applying to said granule an organic solution comprising said material and an organic polyisocyanate, and
- (b) applying to said granule an aqueous solution comprising water and a catalytic amount of a catalyst selected from the group consisting of a basic organic tertiary amine and an alkyl tin carboxylate.
An article of manufacture which comprises a porous granule impregnated with a material which is at least partially immiscible with water, the pores of which are sealed with a porous polyurea membrane formed by
- (a) applying to said granule an organic solution comprising said material and an organic polyisocyanate, and
- (b) applying to said granule an aqueous solution comprising water and a catalytic amount of a catalyst selected from the group consisting of a basic organic tertiary amine and an alkyl tin carboxylate.
Dependencies are inferred from the claim text.