Abstract:
A solution containing an inorganic hypochlorite in aqueous solution and an acetic acid and citric acid mixed with water which when applied to mold bearing surfaces removes mold without harming the surfaces of the object being cleaned and remains active preventing mold growth for a long period of time.

Description:
RELATED APPLICATIONS 
     Related applications are U.S. Provisional Application Ser. No. 60/625,161 filed Nov. 5, 2004 and U.S. Provisional Application Ser. No. 60/732,667 filed Nov. 3, 2005 from which priority is claimed. 
    
    
     FIELD OF INVENTION 
     The present invention is generally directed toward a mold and mildew cleaning and removal composition which is applied to a surface having organic biological colonies present on the surface. 
     BACKGROUND OF THE INVENTION 
     This invention generally relates to the art of disinfecting and more particularly to cleaning inanimate objects with an aqueous hypochlorite solution which retains its fungicidal activity for a significant period of time. 
     Numerous compositions containing hypochlorite are known for treating a surface so as to prevent or remove unwanted biological material. Hypochlorite solutions have been used for many years as germicides, sporicides, virucides and chemical warfare decontamination. However, their prior use has been generally limited due to the inherent corrositivity of hypochlorites and the relatively short effective life span when the same is used to clean and disinfect inanimate objects. 
     1. Field of the Invention 
     The present invention relates to a process for applying an alkali-metal hypochlorite aqueous solution combined with acetate and citrate salts to remove and destroy fungus and bacteria and a composition for same. 
     Sodium, potassium, lithium, and calcium hypochlorites are well known for their disinfecting and bleaching properties. 
     The aqueous hypochlorite solution of the instant invention is useful for removing and destroying mold, mildew, slime and algae on various surfaces, including but not limited to natural and painted/stained wood, aluminum and vinyl siding, brick, grout, stone, cement, stucco, ceramic tile, and the like and for structural items such as boats, machinery and roofs. The term mildew is used to refer generally to undesirable micro organisms which grow on surfaces including mold and algae and combinations of same. 
     2. Discussion of the Prior Art 
     Prior art in this area is exemplified by U.S. Pat. No. 4,097,395 issued Jun. 27, 1978 which discloses a mold and mildew removal composition utilizing bleach, water and acetic acid and by U.S. Pat. No. 3,717,580 issued Feb. 20, 1973, which is directed toward a disinfecting decontaminating solution comprising citrate and hypochlorite. The novel feature of this solution is its “ability”to self-destruct after a short period of germicidal activity with the stated advantage that such a system allows use of a powerful disinfectant such as sodium hypochlorite to be used on sensitive materials without undue exposure of the treated surface to the disinfectant. 
     The use of citrates and malates as disclosed in the aforementioned &#39;580 patent, destroys residual hypochlorite on treated materials and it does not permit control or prolonging of the contact time. 
     U.S. Pat. No. 5,281,280 issued Jan. 25, 1994 discloses the use of an aqueous solution for removing mildew, mold and algae from various types of surfaces. The solution contains sodium hypochlorite ranging from 2.75% to 4.0% by weight, sodium bicarbonate, and about 0.5-5% d-limonene in various ratios. The d-limonene acts as both a degreasing agent and an odor masking agent which covers the sodium hypochlorite odor. The composition was found to be effective against microorganisms such as mildew, molds and algae. An alternative embodiment, #6004 Citrus can be substituted for the d-limonene at a percentage of 0.5% by weight. 
     It can thus be seen that there is a need for a long lasting composition which will remove existing mold and algae and prevent regrowth of the same on the surface which has been cleaned. 
     SUMMARY OF THE INVENTION 
     The present invention is directed toward a composition for removing mold from articles comprising an aqueous solution of inorganic hypochlorite, the salt being NaClO ranging in weight from about 0.5% to about 6% by weight of the composition, combined with a citrate salt ranging from 0.05% to about 6.9% by weight of the composition and an acetate salt ranging from about 0.02% to about 3.2% by weight of the composition added to water. The composition is applied to the surface to be cleaned and then rinsed off with a water wash. 
     Accordingly, one object of this invention is to provide a method of disinfecting and cleaning materials harboring mold and mildew using a new aqueous hypochlorite containing composition. 
     Another object of this invention is to provide a new aqueous hypochlorite containing a number of acids which synergistically work together to prevent reoccurrence of mold and mildew and removal of same. 
     Another object of this invention is to provide a new aqueous hypochlorite containing a number of salts which synergistically work together to prevent reoccurrence of mold and mildew and removal of same. 
     A still further object of this invention is to provide hypochlorite containing composition which remain fungicidal active for a long period of time. 
     Another object of this invention is to provide a composition which is characterized by economy and simplicity of manufacture and ease of use. 
     It is another object of this invention to provide an aqueous disinfectant solution containing an organic sodium hypochlorite salt and an acetic acid and citric acid which synergistically interact to provide a long lasting effective fungicide and cleaner. 
     It is still another object of the invention to provide a composition which works immediately on contact to remove mildew and/or mold from a variety of surfaces. 
     It is yet another object of the invention to provide a composition which leaves no visible film on a treated surface and does not damage the surface. 
     It is also another object of the invention to provide a composition for removing mold and mildew which is suitable for everyday use. 
     These and other objects, advantages, and novel features of the present invention will become apparent when considered with the teachings contained in the detailed disclosure. 
    
    
     DESCRIPTION OF THE INVENTION 
     A number of tests were performed on raw wood, painted wood, brick, mortar, cement and siding as well as other surfaces as noted in the field of the invention to demonstrate the efficiency of the desired ranges of the components of the inventive compositions on different surfaces. Ambient temperature was maintained during the tests and all of the tests resulted in removal of the mildew/mold with no damage to treated surface. 
     At this point, it should be noted that hypochlorite (bleach) by itself is known to kill mold and mildew; however, when bleach is applied to a mildewed surface, although it kills mold and mildew, it does not remove the whole mold and mildew colony. Indeed, at times, mold and mildew that has been killed with bleach is often visible, and a discoloration often appears on a mildewed surface treated with bleach. Furthermore, at other times, only the pigmented spore structure of the surface is killed, and while visibly decolorized and seemingly clean, the base of the mold and mildew colony has not been effectively killed allowing the mold and the mildew to grow back after only a short period of time. The cleaning with bleach is effective for only a short period of time after which the mold and mildew grows back upon the surface. 
     The mold and mildew remover of the present invention, however, not only kills all of the mold and mildew but removes it without abrasive scrubbing. Indeed, a major advantage of the mold and mildew remover of the present invention is that its use eliminates the need to hand scrub a surface. When the teachings of the present invention are followed, the oxidizing agent, namely, the bleach as enabled by the acetate and citrate salts or by the acetic acid and citric acid, not only kills the mold and mildew but also enables the remover to dissolve and remove it to produce a visibly clean surface. 
     In accordance with the present invention, the preferred organic acids components for incorporation into the mold and mildew remover concentrate are acetic acid and citric acid which together form the organic acid ingredients in the concentrate. Facts influencing the choice of the acetate and citrate salts are their water solubility as well as their synergistic effect with hypochlorite. 
     The preferred inorganic hypochlorite salts are sodium, calcium, potassium and lithium. However, the hypochlorite NaClO is preferably used to provide the disinfectant qualities of solution composition since it is generally known that the hypochlorite ion is the source of the active disinfecting agent and not the cation. 
     It is also envisioned, but not necessary, to also add a detergent or detergent mixture to the disinfecting solution for the purpose of enhancing wetting. Any anionic or non-ionic surfactant may be used for this purpose but one should not use cationic surfactants. The surfactant which is preferably used is an anionic surfactant such as sodium dodecyl diphenyloxide disulfonate which is manufactured by the Dow Chemical Company under the trademark DOEFAC 2A1. Generally, the detergent may be present for about 0.2% to about 0.6% by weight but, in any event, the amount used is not critical. When the two organic acids or salts are added to the composition, the pH has a value which is slightly higher than the commercially available hypochlorite solutions. 
     The present inventive composition is an aqueous solution containing a bleach or hypochlorite ranging from about 0.5% to about 6.0% by weight of the composition combined with acetic acid ranging from 0.02% to 2.0% by weight and citric acid ranging from 0.03% to 3.0% by weight or acetate salts ranging from 0.02% to 3.2% by weight and citrate salts ranging from 0.05% to 6.9% by weight with the remaining percentage by weight being water. 
     If desired, a stabilizer for the bleach in the form of alkyl benzene sulfate is commercially available from the Dow Corning Chemical Company which can be used in a range of about 0.02% to about 0.30% by weight to provide for bleach stability. Other additives which can be used are alkali metal alkyl sulfates and alkyl aryl sulfonates. 
     Fragrance may be added to the formulation. 
     A preferred embodiment and best mode of the invention is sodium hypochlorite ranging from about 2.6% to about 6.0% by weight of the composition having from about 0.1% to about 1.1% sodium acetate salt by weight of the composition and from about 0.2% to about 2.4% sodium citrate salt by weight of the composition with the remaining percentage by weight being water. A surfactant and fragrance can be added as desired. While the acetate and citrate salts are noted as being a sodium inorganic salt, it is envisioned that calcium, potassium and lithium could be substituted for the sodium portion of the respective salt. 
     The most preferred embodiment is sodium hypochlorite ranging from about 4.0% to about 6.0% by weight of the composition and from 0.17% to 0.25% sodium acetate salt by weight of the composition and from 0.39% to about 0.54% sodium citrate salt by weight of the composition with the remaining percentage by weight being water. 
     Typical formulations of the present hypochlorite solution are as follows: 
     EXAMPLE 1 
     
       
         
               
               
               
             
               
               
               
             
           
               
                   
                   
               
               
                   
                 Formulation 
                 Percent by weight 
               
               
                   
                   
               
             
             
               
                   
               
             
          
           
               
                   
                 Sodium Hypochlorite (13%) 
                 39.50 
               
               
                   
                 Acetic Acid (99%) 
                 0.20 
               
               
                   
                 Citric Acid (anhy pwr) 
                 0.30 
               
               
                   
                 Water 
                 60.00 
               
               
                   
                 Total: 
                 100.00 
               
               
                   
                   
               
             
          
         
       
     
     EXAMPLE 2 
     
       
         
               
               
               
             
               
               
               
             
           
               
                   
                   
               
               
                   
                 Formulation 
                 Percent by weight 
               
               
                   
                   
               
             
             
               
                   
               
             
          
           
               
                   
                 Sodium Hypochlorite (6.5%) 
                 39.00 
               
               
                   
                 Acetic Acid (99%) 
                 0.40 
               
               
                   
                 Citric Acid (anhy pwr) 
                 0.60 
               
               
                   
                 Water 
                 60.00 
               
               
                   
                 Total: 
                 100.00 
               
               
                   
                   
               
             
          
         
       
     
     EXAMPLE 3 
     
       
         
               
               
               
             
               
               
               
             
           
               
                   
                   
               
               
                   
                 Formulation 
                 Percent by weight 
               
               
                   
                   
               
             
             
               
                   
               
             
          
           
               
                   
                 Sodium Hypochlorite (13%) 
                 39.52 
               
               
                   
                 Acetic Acid (99%) 
                 0.17 
               
               
                   
                 Citric Acid (anhy pwr) 
                 0.31 
               
               
                   
                 Water 
                 60.00 
               
               
                   
                 Total: 
                 100.00 
               
               
                   
                   
               
             
          
         
       
     
     EXAMPLE 4 
     
       
         
               
               
               
             
               
               
               
             
           
               
                   
                   
               
               
                   
                 Formulation 
                 Percent by weight 
               
               
                   
                   
               
             
             
               
                   
               
             
          
           
               
                   
                 Sodium Hypochlorite (13%) 
                 39.53 
               
               
                   
                 Sodium Acetate 
                 0.21 
               
               
                   
                 Sodium Citrate 
                 0.46 
               
               
                   
                 DOWFAX 2A1 
                 0.60 
               
               
                   
                 Fragrance 
                 0.15 
               
               
                   
                 Water 
                 59.05 
               
               
                   
                 Total: 
                 100.00 
               
               
                   
                   
               
             
          
         
       
     
     EXAMPLE 5 
     
       
         
               
               
               
             
               
               
               
             
           
               
                   
                   
               
               
                   
                 Formulation 
                 Percent by weight 
               
               
                   
                   
               
             
             
               
                   
               
             
          
           
               
                   
                 Sodium Hypochlorite (13%) 
                 39.53 
               
               
                   
                 Sodium Acetate 
                 0.02 
               
               
                   
                 Sodium Citrate 
                 0.05 
               
               
                   
                 DOWFAX 2A1 
                 0.60 
               
               
                   
                 Fragrance 
                 0.15 
               
               
                   
                 Water 
                 59.65 
               
               
                   
                 Total: 
                 100.00 
               
               
                   
                   
               
             
          
         
       
     
     EXAMPLE 6 
     
       
         
               
               
               
             
               
               
               
             
           
               
                   
                   
               
               
                   
                 Formulation 
                 Percent by weight 
               
               
                   
                   
               
             
             
               
                   
               
             
          
           
               
                   
                 Sodium Hypochlorite (13%) 
                 39.53 
               
               
                   
                 Sodium Acetate 
                 2.13 
               
               
                   
                 Sodium Citrate 
                 4.62 
               
               
                   
                 DOWFAX 2A1 
                 0.60 
               
               
                   
                 Fragrance 
                 0.15 
               
               
                   
                 Water 
                 52.97 
               
               
                   
                 Total: 
                 100.00 
               
               
                   
                   
               
             
          
         
       
     
     EXAMPLE 7 
     
       
         
               
               
               
             
               
               
               
             
           
               
                   
                   
               
               
                   
                 Formulation 
                 Percent by weight 
               
               
                   
                   
               
             
             
               
                   
               
             
          
           
               
                   
                 Sodium Hypochlorite (13%) 
                 19.77 
               
               
                   
                 Sodium Acetate 
                 0.21 
               
               
                   
                 Sodium Citrate 
                 0.46 
               
               
                   
                 DOWFAX 2A1 
                 0.60 
               
               
                   
                 Fragrance 
                 0.15 
               
               
                   
                 Water 
                 78.81 
               
               
                   
                 Total: 
                 100.00 
               
               
                   
                   
               
             
          
         
       
     
     EXAMPLE 8 
     
       
         
               
               
               
             
               
               
               
             
           
               
                   
                   
               
               
                   
                 Formulation 
                 Percent by weight 
               
               
                   
                   
               
             
             
               
                   
               
             
          
           
               
                   
                 Sodium Hypochlorite (13%) 
                 19.77 
               
               
                   
                 Sodium Acetate 
                 0.63 
               
               
                   
                 Sodium Citrate 
                 1.38 
               
               
                   
                 DOWFAX 2A1 
                 0.60 
               
               
                   
                 Fragrance 
                 0.15 
               
               
                   
                 Water 
                 77.47 
               
               
                   
                 Total: 
                 100.00 
               
               
                   
                   
               
             
          
         
       
     
     EXAMPLE 9 
     
       
         
               
               
               
             
               
               
               
             
           
               
                   
                   
               
               
                   
                 Formulation 
                 Percent by weight 
               
               
                   
                   
               
             
             
               
                   
               
             
          
           
               
                   
                 Sodium Hypochlorite 
                 5.14 
               
               
                   
                 Sodium Acetate 
                 0.21 
               
               
                   
                 DOWFAX 2A1 
                 0.60 
               
               
                   
                 Water 
                 94.05 
               
               
                   
                 Total: 
                 100.00 
               
               
                   
                   
               
             
          
         
       
     
     EXAMPLE 10 
     
       
         
               
               
               
             
               
               
               
             
           
               
                   
                   
               
               
                   
                 Formulation 
                 Percent by weight 
               
               
                   
                   
               
             
             
               
                   
               
             
          
           
               
                   
                 Sodium Hypochlorite 
                 5.14 
               
               
                   
                 Sodium Citrate 
                 0.46 
               
               
                   
                 DOWFAX 2A1 
                 0.60 
               
               
                   
                 Water 
                 93.80 
               
               
                   
                 Total: 
                 100.00 
               
               
                   
                   
               
             
          
         
       
     
     EXAMPLE 11 
     
       
         
               
               
               
             
               
               
               
             
           
               
                   
                   
               
               
                   
                 Formulation 
                 Percent by weight 
               
               
                   
                   
               
             
             
               
                   
               
             
          
           
               
                   
                 Sodium Hypochlorite 
                 5.14 
               
               
                   
                 Sodium Acetate 
                 0.21 
               
               
                   
                 Sodium Citrate 
                 0.46 
               
               
                   
                 DOWFAX 2A1 
                 0.60 
               
               
                   
                 Water 
                 93.59 
               
               
                   
                 Total: 
                 100.00 
               
               
                   
                   
               
             
          
         
       
     
     
       
         
               
               
               
               
               
             
               
               
               
               
               
             
           
               
                 TABLE I 
               
               
                   
               
               
                   
                 Example 4 
                   
                   
                 Most 
               
               
                 Component 
                 Formulation 
                 Broad Range 
                 Preferred 
                 Preferred 
               
               
                   
               
             
             
               
                   
               
             
          
           
               
                 Sodium Acetate 
                 0.21 
                 0.02-3.2 
                 0.1-1.1 
                 0.17-0.25 
               
               
                 Sodium Citrate 
                 0.46 
                 0.05-6.9 
                 0.2-2.4 
                 0.38-0.54 
               
               
                 NaOCl* 
                 5.2 
                 0.5-6  
                 2-6 
                 4-6 
               
               
                   
               
             
          
         
       
     
     The formulations of this composition have been used to clean mold and mildew from cut lumber, aluminum and vinyl siding, cement, stone, bricks, grout and the like and to prevent mold growth for up to one year without additional treatment. The composition was applied to the surface of the object by spraying the composition onto the surface using a standard spray bottle or by brushing the same onto the surface using a standard brush. If desired, the composition could be pressured under gas and foamed onto the surface. 
     The solution of Example 4 was used to remove mold and mildew from pine decking wood (approx. 10×36 inches). The solution was sprayed onto the wood under ambient conditions until the surface was thoroughly saturated and then allowed to stand on the surface. The black and green coloration of the surface began to disappear upon initial contact of the solution with the wood surface. After four minutes the surface was rinsed with flowing water and allowed to dry. No mold and mildew stains were observed on the surface. 
     The solutions of Examples 4, 5, and 6 were evaluated in the same manner as previously noted above (wood dimensions approximately 10×10 inches). The solution was allowed to remain on the surface for approximately six minutes before rinsing with flowing water. In Example 5, some black discoloration remained on the surface. In Example 6, no mold and mildew stains remained on the surface of the wood. Black and green coloration of the surface began to disappear upon initial contact with the solution. 
     The solutions of Examples 7 and 8 were evaluated in the same manner as initial Example 4 above (wood dimensions approximately 10×10 inches). The solution was allowed to remain on the surface for approximately six minutes before rinsing with flowing water. No mold and mildew stains were observed on the surface. The surface treated with the solution of Example 8 was brighter than that treated with solution of Example 7. Likewise, the black and green coloration of the surface disappeared more quickly upon initial contact with the solution of Example 8 than that of Example 7. 
     The solutions of Examples 9, 10, and 11 were evaluated in the same manner as noted in the first discussion of Example 4 (wood dimensions approximately 10×10 inches). In Example 9, some black discoloration remained on the surface. In Example 10, some black discoloration remained on the surface although the surface was brighter overall from that of the solution of Figure 9. In Example 11, no mold and mildew stains remained on the surface. Black and green coloration of the surface began to disappear upon initial contact with the solution. 
     This demonstrates the synergistic effect of sodium acetate and sodium citrate in the effective removal of mold and mildew. 
     The solutions of Examples 4, 7 and 8 were also used to remove mold and mildew from asphalt roofing material (approx. 4×4 feet). The solution was sprayed onto the roofing material under ambient conditions until the surface was thoroughly saturated and then allowed to stand on the surface. The black coloration of the surface began to disappear upon initial contact of the solution with the roofing material. After five minutes for the solution of Example 4 and after ten minutes for the solutions of Examples 7 and 8, the surfaces were rinsed with flowing water and allowed to dry. No mold and mildew stains were observed on the surfaces. 
     Similarly, the solutions of Examples 4, 7, and 8 were used to effectively remove mold and mildew stains from stucco, vinyl and aluminum siding, wood fencing, brick, mortar, grout, tile and shower surfaces. 
     After application, the composition was allowed to remain on the surface from about 1 minute to 2 minutes depending upon the density of the mold and/or mildew and then rinsed off with ordinary tap water. 
     The principles, preferred embodiments and modes of operation of the present invention have been described in the foregoing specification. However, the invention should not be construed as limited to the particular embodiments which have been described above. Instead, the embodiments described here should be regarded as illustrative rather than restrictive. Variations and changes may be made by others without departing from the scope of the present invention as defined by the following claims.