Enzyme-containing heavy duty liquid detergent

#Liquid laundry detergents provide the same performance benefits as powdered detergents such as whole wash cleaning, whitening, antiredeposition and odor removal, while providing additional benefits such as convenient dispensing, complete solubility and improved stain removal on localized stains. The improved localized cleaning is accomplished by pretreating the stain directly without the need to make a paste as with powder detergents. Liquid laundry detergents have become increasingly popular in recent years due in large part to these advantages over powders.

#Liquid detergents encounter formulation difficulties over and above those seen in powders largely due to the desire to keep a wide variety of surfactants, builders and other cleaning agents solubilized for long periods in a homogeneous free flowing form. Many of the chemicals available and desirable for use in liquids are physically as well as chemically incompatible. Much of the skill utilized in formulating liquid detergents goes into keeping these chemicals stable for long periods in intimate contact with incompatible materials.

#Over the last ten to twenty years, the addition of enzyme to laundry detergents for stain removal has become commonplace, particularly in Europe. Many laundry detergents now contain one or more proteolytic and/or amylolytic enzymes to improve their performance on stains that are either protein- or starch-based, such as those caused by blood, milk, grass or fruit juices. Incorporation of enzymes into powder detergents has become common, since in powders the enzymes are not in intimate contact with surfactants and other chemicals which cause degradation of the enzyme and consequent loss of enzyme activity as well as decreased effectiveness.

#The liquid laundry detergents described in this invention contain the following components either as essential components or as optional ingredients: surfactants (either anionic, nonionic, cationic, zwitterionic or amphoteric or mixtures thereof) for detergency, both whole wash and pretreatment, builders for hardness ion sequestration, alkalinity/buffering agents for pH maintenance both in the neat liquid and upon dilution in the whole wash, solubilizers or hydrotropes for phase stability of the active in solution, enzymes (protease, and optionally amylase, cellulase, lipase or mixtures thereof) for stain removal, polyhydric alcohols and/or boron compounds to preserve enzyme activity upon storage, fluorescent whitening agents for whitening and brightening of clothing, softeners, foam control agents, appearance modifiers such as thickeners or opacifiers, bluing agents and colorants, germicides, perfumes and preservatives. Additional performance agents such as bleaching agents (either chlorine or oxygen bleaching), soil release agents, antiredeposition or soil suspending agents, solvents, or other minor performance components may optionally be added. Each of these components, both essential and optional, are discussed in greater detail as follows:

#Surfactants

#While cationic, zwitterionic or amphoteric surfactants are acceptable for use and may be considered within the scope of this invention, anionic or nonionic surfactants and mixtures thereof are more commonly used in formulating liquid laundry detergents. A ternary surfactant system of linear alkyl benzene sulfonate, linear ether sulfate and ethoxylated alcohol nonionic is especially preferred. The ratio of anionic to nonionic surfactants is preferably 1:1 to 10:1. Suitable zwitterionics and amphoteric surfactants are described in U.S. Pat. No. 4,528,039 while suitable cationic surfactants are described in U.S. Pat. No. 4,497,718, which patents are hereby incorporated by reference. The compositions of the invention may include from 1-60% by weight of one or more surfactants. The preferred anionic and nonionic surfactants are described in more detail as follows: