Encapsulated enzyme in dry bleach composition
Reference Number: N 03-07
Inventors: Deleeuw, David L.; Steichen, Dale S.; Mitchell, James D.
Owner: NISTAC
USPTO Link:5254287
Invention Summary
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.