Encapsulated enzyme in dry bleach composition
Reference Number: N 03-07
Inventors: Deleeuw, David L.; Steichen, Dale S.; Mitchell, James D.
The present invention relates to enzyme-containing oxidant bleach compositions, especially organic diperacid based bleaching products. More specifically, compositions provide enzyme stability during prolonged storage in the presence of oxidants, while supporting enzyme solubility.
The improved product is prepared by coating or encapsulating the enzyme or enzymes with a material which both effectively renders the enzyme resistance to degradation in bleach products and allows for sufficient solubility upon introduction into an aqueous medium, such as found during laundering. Particularly, alkaline materials act as protective agents, which neutralize oxidant species before they contact and denature the enzyme. Exemplary of such protective agents are sodium silicate and sodium carbonate, both of which act to physically block the attack of the enzyme by oxidants, and to chemically neutralize the oxidants. Active protective agents also include reducing materials, such as sodium sulfite and sodium thiosulfate, and antioxidants such as BHT (butylated hydroxytoluene) and BHA (butylated hydroxyanisole), which act to inhibit radical chain oxidation. Transition metals, especially iron, cobalt, nickel, and copper, act as catalysts to speed up the breakdown of oxidant species and thus protect the enzymes. These active enzyme protective agents may be used in conjunction with carriers, especially water-soluble polymers, which do not of themselves protect the enzyme, but which provide enhanced solubility and act as dispersant agents or carriers for protective agents.
Standard bleaching composition adjuncts such as builders, fillers, buffers, brighteners, fragrances, and the like may be included in an enzyme-containing oxidant bleach composition in addition to the discrete enzyme granules, and the oxidant bleach.