Patent Publication Number: US-7214652-B1

Title: Anionic surfactant-containing hypochlorite bleach composition and methods of making and use

Description:
FIELD   
     The present invention relates to liquid hypochlorite bleaching compositions, in particular those useful in treating fabrics, and methods of making and using such compositions. 
     BACKGROUND 
     Hypochlorite liquid bleaches have found wide commercial acceptance and are commonly used in a variety of household cleaning and laundering products. However, there are certain limitations to the utility of hypochlorite bleaches. 
     One limitation of hypochlorite bleaches is the aroma which is typically considered distinctive and disagreeable. To address this, it is known to incorporate fragrances in bleach compositions to impart a more desirable aroma thereto. U.S. Patent No. 5,080,826 (Colborn et al.) discloses a stable, fragranced liquid hypochlorite bleach composition. U.S. Pat. Nos. 3,876,551 (Laufer et al.) and 4,390,448 (Borden et al.) disclose stable alkali metal hypochlorite liquid solutions containing perfumes and certain amide oxide or anionic surfactants. 
     Another well known limitation of hypochlorite bleaches is that in addition to providing desired whitening or bleaching of a garment, treatment with hypochlorite bleaches tends to make garments look worn and undergo pilling after several washings as the bleach composition tends to attack the fibers. In some instances, garments or other fabric articles treated with hypochlorite bleach will even develop holes. 
     SUMMARY 
     It has been discovered that hypochlorite bleach compositions containing emulsions of certain softeners and certain stabilizing surfactants as described herein will provide heretofore unattained shelf stability and performance. Compositions of the invention provide effective bleaching performance while imparting reduced wear and degradation and enhanced softness to the treated fabric article. 
     The present invention relates to new hypochlorite bleach compositions that provide a number of advantages as compared to previously known hypochlorite bleach compositions. Compositions of the invention provide excellent bleaching performance, provide longer shelf life and are more storage stable, and provide more gentle conditioning of fabrics, resulting in less degradation of the fabrics when compositions of the invention are used. The invention provides new bleach compositions, methods for making such compositions, and methods for using such compositions. 
     In brief summary, compositions of the invention comprise an aqueous mixture of an alkali metal hypochlorite and softener emulsion containing an anionic stabilizing surfactant. 
     Briefly summarizing, compositions of the invention may be made by providing a softener emulsion containing an anionic stabilizing surfactant and mixing such emulsion with an aqueous alkali metal hypochlorite solution. 
     In brief summary, compositions of the invention may be used to treat articles, e.g., fabrics and other garments, in conventional manner. 
    
    
     DETAILED DESCRIPTION OF ILLUSTRATIVE EMBODIMENTS 
     In brief summary, treatment compositions of the invention are aqueous liquid compositions comprising alkali metal hypochlorite and a softener emulsion of certain fabric softener components containing anionic stabilizing surfactant, and optionally, desired adjuvants and additives. 
     The alkali metal hypochlorite used in the present invention is selected from the group consisting of: sodium hypochlorite, potassium hypochlorite, lithium hypochlorite, and mixtures thereof. 
     If desired, the pH of the bleach composition may be adjusted, typically preferably to a range of about 10 to about 14. For example, a sufficient quantity of one or more alkali metal hydroxides, e.g., selected from the group consisting of lithium hydroxide, potassium hydroxide, sodium hydroxide, and mixtures thereof may be added to the composition. If the pH of the bleach composition is too low it will tend to lose effectiveness more quickly, i.e., will exhibit a relatively shorter shelf life than would otherwise be the case. 
     The temperature at which compositions of the invention remain both substantially stable and commercially useful for the purposes set forth herein varies from approximately 20° F. (−7° C.) up to approximately 120° F. (50° C.). At temperatures below about 20° F. the composition will typically separate into a two-phase system and at temperatures higher than about 120° F. the bleaching or sterilizing efficiency of the composition of the invention is diminished at an excessive rate. 
     Treatment compositions of the invention will typically comprise from about 1 to about 16 weight percent, typically preferably from about 3 to about 5 weight percent, of alkali metal hypochlorite. Compositions comprising lesser amounts of hypochlorite may tend to be less effective than desired. Compositions comprising greater amounts of hypochlorite will typically be more corrosive and potentially more troubling to work with. 
     Fabric softeners used in the present invention are preferably polyethylene-based. Illustrative examples include oxidized polyethylene, polyethylene acrylic acid, polyethylene/polypropylene, polypropylene, polyethylene, polyethylene/paraffin wax emulsions, and combinations thereof. 
     In order to make a bleaching composition of the invention, an aqueous emulsion of the softener is prepared. Typically, an aqueous emulsion of the softener is prepared with other surfactant(s), e.g., one or more ionic or non-ionic surfactants, to yield a preliminary emulsion and then augmented by addition of one or more stabilizing surfactants as described herein. This permits selection of emulsifying surfactants based on desired emulsion properties and then selection of a different stabilizing surfactant in accordance with the present invention based on desired performance in the bleach composition. 
     The emulsions may be prepared via any of various known techniques. The size of the emulsion particles can be controlled by selection of emulsifying conditions, e.g., temperature, pressure, and surfactant level. The particles of softening within the emulsion are typically from about 0.020 to about 0.2 microns in size, preferably from about 0.035 to about 0.07 microns in size. 
     The aqueous emulsion is then augmented by adding an anionic stabilizing surfactant such as is discussed below before being added to the bleach composition. 
     Some commercially available softener emulsions may be used in the present invention. Illustrative examples of commercially available emulsions that can be used herein include FLUFTONE® POLYETHYLENE Softeners from Apollo Chemical Company of Burlington, N.C., and FABRITONE® Fabric Softeners from Noveon, Inc. of Cleveland, Ohio. 
     Typically, a treatment composition of the invention will contain from about 1 to about 15 weight percent, typically from about 5 to about 8 weight percent, of softener. 
     The stabilizing surfactant is an anionic surfactant or blend of such surfactants. Preferably the surfactant does not contain significant oxidizable functionality. 
     It has been unexpectedly discovered that certain anionic surfactants protect the softener emulsion in the bleach composition such that it will impart useful benefits to fabrics treated with the bleach composition while also inhibiting or preventing consumption of the hypochlorite components during storage such that the composition retains more effective bleaching capability when it is used. 
     Illustrative examples of anion surfactants useful herein include those of the formula:
 
R 3  (C 6 H 10 )(SO 3 M 1 )O(C 6 H 9 )(SO 3 M 2 )
 
wherein R 3  is a straight or branched chain alkyl comprising from 6 to 18 carbon atoms and M 1  and M 2  are the same or different and each is an alkali metal such as sodium, potassium or lithium. One illustrative example of such anionic surfactants is DOWFAX™ 2A1 from Dow Chemical Company.
 
     Typically the softener emulsion will contain from about 5 to about 50 weight percent of such surfactant compositions when blended into bleach compositions of the invention. 
     Bleaching compositions of the invention can be prepared as follows. 
     Providing an aqueous emulsion of suitable softener containing a stabilizing surfactant as described above. 
     The pH range of the aqueous alkali metal hypochlorite solutions of the invention is typically from about 11.0 up to about 14.0. The requisite pH range is achieved by adding an aqueous solution of alkali metal hydroxide (e.g., from 1 molar up to 12.5 molar) to the alkali metal hypochlorite solution which has had or will have added to it the softener emulsion containing a stabilizing surfactant. 
     Following mixing, the bleach composition is then stored. An advantage of the present invention is that the composition can be stored under room temperature conditions for several weeks or more while retaining good bleaching effectiveness and improved fabric protection as described above. 
     The hypochlorite bleach composition may, if desired, also contain additional components such as buffers, primary cleansing agents (surfactants), detergents, builders, fluorescent whitening agents, stainblockers, fragrances, pigments, dyes, thickening agents, and defoamers. Buffers preferably comprise one or more of a pH adjusting agent effective to adjust or to maintain the pH of a solution (e.g., wash liquor) in which the hypochlorite bleach composition is added to a pH greater than about 10. Suitable pH adjusting agents, are well known to the art and include, for example, carbonates, borates, phosphates, silicates, and bicarbonates. 
     In some embodiments, bleach compositions of the invention will be substantially free of whitening agents. 
     Fragrances are usually blends of volatile oils that are composed of organic compounds such as esters, aldehydes, ketones or mixtures thereof. Such fragrances are usually proprietary materials commercially available from such manufacturers as Quest, International Flavors and Fragrances, Givaudan and Firmenich, Inc. Examples of fragrances which may be suitable for use in the present invention may be found in Laufer et al., U.S. Pat. No. 3,876,551, and Boden et al, U.S. Pat. No. 4,390,448, which are incorporated herein. Stable fragranced hypochlorite bleaching compositions are described, for example, in U.S. Pat. No. 5,080,826. 
     Compositions of the invention may be readily used. In a typical embodiment, an effective amount of the bleach composition will be contacted to an article, e.g., a fabric article, which is desired to be treated. For example, a desired quantity of the liquid bleach composition may be added to vessel such as a wash tub or basin in which water is already present and then subject articles to be treated are present. 
     Compositions of the invention will typically be applied to fabric articles, e.g., garments, bolts of fabric, etc. Typically the fabric articles will comprise natural fibers such as wool and cotton. It will be understood, however, that compositions of the invention may be used on other articles, e.g., non-fabric articles, or fabric articles made of other fibers, if desired. 
     EXAMPLES 
     The invention will now be explained with the following non-limiting examples. 
     Surfactant Stability in Bleach 
     The following procedure was used to determine the stability of various surfactants in bleach. 
     To 5 grams of surfactant was added 10% sodium hydroxide solution to adjust the pH to approximately 13. To this was slowly added 94 to 95 g of liquid bleach (Target™ Bleach) and the mixture was allowed to stir for 10 minutes. Stability was tested by visual appearance of the solution at room temperature and after accelerated aging at 50° C. The stability data is summarized in Table 1. 
     
       
         
           
               
               
             
               
                   
                 TABLE 1 
               
             
            
               
                   
                   
               
               
                   
                 Stability 
               
            
           
           
               
               
               
               
            
               
                   
                 Class of 
                 Room 
                 50° C. for 
               
               
                 Surfactant* 
                 Surfactant 
                 Temperature 
                 2 days 
               
               
                   
               
               
                 DS-10 
                 Sulfates &amp; 
                 Milky-2 
                 Two Layers 
               
               
                   
                 Sulfonates 
                 Layers 
               
               
                 TRITON ™ 
                 Sulfates &amp; 
                 Thick 
                 Two Layers 
               
               
                 QS-15 
                 Sulfonates 
                 Solution 
               
               
                 TRITON ™ 
                 Sulfates &amp; 
                 Cloudy 
                 Milky 
               
               
                 W-30 
                 Sulfonates 
               
               
                 TRITON ™ 
                 Sulfates &amp; 
                 Cloudy 
                 Milky 
               
               
                 XN-45S 
                 Sulfonates 
               
               
                 TRITON ™ 
                 Sulfates &amp; 
                 Cloudy, some 
                 Precipitate 
               
               
                 X-200K 
                 Sulfonates 
                 precipitate 
               
               
                 DOWFAX ™ 
                 Alkyl Diphenyl 
                 Clear Yellow 
                 Clear Yellow 
               
               
                 8390 
                 Oxide Disulfonate 
                 Solution 
                 Solution 
               
               
                   
                 salts 
               
               
                 DOWFAX ™ 
                 Alkyl Diphenyl 
                 Clear Yellow 
                 Clear Yellow 
               
               
                 D 30599 
                 Oxide Disulfonate 
                 Solution 
                 Solution, slight 
               
               
                   
                 salts 
                   
                 precipitate 
               
               
                 DOWFAX ™ 
                 Alkyl Diphenyl 
                 Clear Yellow 
                 Clear Yellow 
               
               
                 2A1 
                 Oxide Disulfonate 
                 Solution 
                 Solution 
               
               
                   
                 salts 
               
               
                 DOWFAX ™ 
                 Alkyl Diphenyl 
                 Clear Yellow 
                 Clear Yellow 
               
               
                 3B2 
                 Oxide Disulfonate 
                 Solution 
                 Solution 
               
               
                   
                 salts 
               
               
                   
               
               
                 *Surfactants: 
               
               
                 DS-10 = Dodecylbenzene sulfonate (SIPONATE ™ from Rhone Poulenc of Cranbury, New Jersey) 
               
               
                 TRITON ™ QS-15 = Polyether sulfate (from Dow Chemical Company, Midland, MI) 
               
               
                 TRITON ™ W-30 = Alkoxylate sulfate (from Dow Chemical Company, Midland, MI) 
               
               
                 TRITON ™ XN-45S = Sulfate (from Dow Chemical Company, Midland, MI) 
               
               
                 TRITON ™ X-200K = Polyether sulfonate (from Dow Chemical Company, Midland, MI) 
               
               
                 DOWFAX ™ 8390, DOWFAX ™ 30599, DOWFAX ™ 2A1, DOWFAX ™ 3B2 = Alkydiphenyloxide Disulfonate salts (from Dow Chemical Company, Midland, MI) 
               
            
           
         
       
     
     The above data suggests that the alkyldiphenyloxide disulfonate salts are more stable in bleach. 
     General Procedure for Fabric Washing and Drying 
     A full size top load washing machine (Sears™ KENMORE™ Elite) was used with the following settings: Normal Wash cycle, Hot/Cold temperature and #10 setting, one rinse, using highest fill. 
     The washing machine was filled with water. The temperature of the hot water averaged approximately 103° F. (40° C.). Approximately 75 grams of regular Tide™ Liquid laundry detergent (available from Procter &amp; Gamble) was then added to the water. This was followed by adding approximately 250 grams of Target™ brand liquid bleach (with or without the additive) into the water, all around the circular tub. The weight of materials washed was approximately 4 pounds dry weight (approximately 10 men&#39;s extra-large t-shirts and 10 washcloths). When the water level reached approximately ¼–⅓ full, the fabrics were placed in the washing machine with an even distribution. At end of each wash cycle, the fabrics were placed into a clothes dryer (Sears™ KENMORE™ Elite) timed for 45 minutes using the highest heat setting (cotton towels/high). 
     Example 1 
     1.25 grams of SIPONATE™ DS-10 anionic surfactant was added to 15 grams of a polyethylene wax emulsion (ME29730, available from Michelman, Inc., Cincinnati, Ohio) and the mixture was allowed to stir for 10 minutes. When it was observed that the solution was homogenous, the pH was raised to about 12 to about 13 by using a 10% aqueous sodium hydroxide solution (approximately 44 drops). Then approximately 223 grams of TARGET™ brand liquid bleach was slowly added to the polyethylene was/surfactant solution and the bleach mixture was allowed to stir for 10 minutes. 
     Fabric appearance was then evaluated after 20 wash/dry laundering cycles (described above) using regular TIDE™ Liquid laundry detergent (75 grams). For comparison fabrics were also evaluated using regular Tide™ Liquid laundry detergent (75 grams) and TARGET™ brand liquid bleach with no additive (250 grams). Five 100% cotton white knit HANES™ t-shirt size extra-large, five FRUIT OF THE LOOM™ 100% cotton white knit size large t-shirts and ten 100% cotton white washcloths with no decoration (WAL-MART brand) were used for a total of approximately four pounds (dry weight). The fabrics were evaluated visually for texture, softness/coarseness, pilling, wear (holes, tears) and whiteness/brightness vs. dinginess/yellowing. The performance data is summarized in Table 2. 
     
       
         
           
               
               
               
             
               
                   
                 TABLE 2 
               
             
            
               
                   
                   
               
               
                   
                   
                 # of 
               
               
                   
                 Appearance 
                 Holes- 
               
            
           
           
               
               
               
               
               
            
               
                 Formula 
                 Feel 
                 Wash Cloths 
                 T-Shirts 
                 T-Shirts 
               
               
                   
               
            
           
           
               
               
               
               
               
            
               
                 Example 4 
                 Softer 
                 Less wear 
                 Less wear 
                 4 
               
               
                   
                   
                 Fibers are 
                 than bleach with 
               
               
                   
                   
                 denser 
                 no additive 
               
               
                   
                   
                 Reduced 
                 Reduced 
               
               
                   
                   
                 yellowing and 
                 yellowing and 
               
               
                   
                   
                 less dingier 
                 less dingier 
               
               
                   
                   
                 than bleach with 
                 than bleach with 
               
               
                   
                   
                 no additive 
                 no additive 
               
               
                 TARGET ™ 
                 Coarse 
                 Fibers are quite 
                 Much wear 
                 61 
               
               
                 Liquid Bleach 
                   
                 worn, stretched 
                 and threadbare 
               
               
                 and TIDE ™ 
                   
                 and 
                 Dingier 
               
               
                 Liquid Laundry 
                   
                 threadbare 
               
               
                 Detergent 
               
               
                 (no additive) 
               
               
                   
               
            
           
         
       
     
     Examples 2–9 
     The following procedure was typical of that used to make the remaining examples summarized in Table 3 of bleach solutions having the polyethylene wax emulsion/surfactant additive. The indicated amount of stabilizing surfactant was added to 6 grams of a polyethylene wax emulsion (ME29730, available from (Michelman Inc., Cincinnati, Ohio) and the mixture was allowed to stir for 10 minutes. When it was observed that the solution was homogenous, the pH was raised to approximately 12 to 13 by using a 10% aqueous sodium hydroxide solution. Then approximately 92 to 93 grams of TARGET™ liquid bleach was slowly added to the polyethylene wax/surfactant solution and the bleach mixture was allowed to stir for 10 minutes. 
     The initial appearance of the bleach composition after mixing was noted. The compositions were then stored at 40° C. and visually examined periodically. The time at which the homogenous composition was observed to have become heterogenous (i.e., no longer clear, separated into separate phases, etc.) is noted in the far right column. 
     
       
         
           
               
               
               
               
               
               
             
               
                 TABLE 3 
               
               
                   
               
               
                   
                   
                 Wax 
                   
                   
                   
               
               
                   
                   
                 Emulsion 
                   
                   
                   
               
               
                   
                   
                 Particle 
                   
                 Appear- 
                   
               
               
                   
                 Wax 
                 Size 
                   
                 ance in 
                   
               
               
                 Example 
                 Emulsion* 
                 (microns) 
                 Surfactant 
                 Bleach 
                 Time 
               
               
                   
               
             
            
               
                   
               
            
           
           
               
               
               
               
               
               
               
            
               
                 Control 
                 ME29730 
                 0.045 
                 NONE 
                 Slightly 
                 &lt;1 
                 day 
               
               
                   
                   
                   
                   
                 hazy 
               
               
                 2 
                 ME29730 
                 0.045 
                 DS-10 (1 g) 
                 Slightly 
                 4 
                 days 
               
               
                   
                   
                   
                   
                 hazy 
               
               
                 3 
                 ME29730 
                 0.045 
                 TRITON ™ 
                 Milky 
                 2 
                 days 
               
               
                   
                   
                   
                 W-30 (1 g) 
                 solution 
               
               
                 4 
                 ME29730 
                 0.045 
                 DOWFAX ™ 
                 Slightly 
                 10 
                 days 
               
               
                   
                   
                   
                 2A1 (1 gram) 
                 hazy 
               
               
                 5 
                 ME29730 
                 0.045 
                 DOWFAX ™ 
                 Slightly 
                 10 
                 days 
               
               
                   
                   
                   
                 2A1 
                 hazy 
               
               
                   
                   
                   
                 (0.5 grams) 
               
               
                 6 
                 ME29730 
                 0.045 
                 DOWFAX ™ 
                 Slightly 
                 10 
                 days 
               
               
                   
                   
                   
                 3B2 (1 gram) 
                 hazy 
               
               
                 7 
                 ME29730 
                 0.045 
                 DOWFAX ™ 
                 Slightly 
                 10 
                 days 
               
               
                   
                   
                   
                 3B2 
                 hazy 
               
               
                   
                   
                   
                 (0.5 grams) 
               
               
                 8 
                 ME32535 
                 0.035 
                 DOWFAX ™ 
                 Slightly 
                 10 
                 days 
               
               
                   
                   
                   
                 2A1 (1 g) 
                 hazy 
               
               
                 9 
                 ME72040 
                 0.175 
                 DOWFAX ™ 
                 Milky 
                 3 
                 days 
               
               
                   
                   
                   
                 2A1 (1 g) 
                 solution 
               
               
                 10 
                 ME43040 
                 0.045 
                 DOWFAX ™ 
                 Slightly 
                 5 
                 days 
               
               
                   
                   
                   
                 2A1 (1 g) 
                 hazy 
               
               
                   
               
               
                 *ME29730, ME32535, and ME72040 are all polyethylene wax emulsions and are available from Michelman, Inc., Cincinnati, Ohio. 
               
            
           
         
       
     
     The data in Table 3 suggests that when additional surfactants are added to a solution of the polyethylene wax additive and bleach, the stability of the additive in bleach improves. The anionic surfactants of the sulfates and sulfonates type improve the stability of the polyethylene wax additive in bleach compared to the control (no post added surfactant). Alkydiphenyloxide disulfonate salts type surfactants when post added to the wax emulsion seem to show further enhancement in keeping the additive stable after it is mixed with a bleach solution. 
     Various modifications and alterations to this invention will become apparent to those skilled in the art without departing from the scope and spirit of this invention. It should be understood that this invention is not intended to be unduly limited by the illustrative embodiments and examples set forth herein and that such examples and embodiments are presented by way of example only with the scope of the invention intended to be limited only by the claims set forth herein as follows.