Abstract:
A diphase drain cleaning composition and method wherein the composition has two liquid layers. The lower, denser layer makes up from 50 to 99 percent of the total composition weight while the upper, less-dense layer makes up from 1 to 50 percent of the total composition weight. The lower layer consists of at least 20 percent sulfuric acid solution. The upper layer consists of a halogenated aliphatic hydrocarbon polystyrene solvent and, optionally, fully saturated aliphatic hydrocarbons. The composition attacks drain blockage consisting of polystyrene and other organic and inorganic matter in two phases. First, the lower layer of sulfuric acid contacts the blockage and melts and dissolves many organic and inorganic materials. Second, loosened polystryene, which is not affected by the sulfuric acid, floats to the upper layer where it is dissolved by the solvent making up the upper layer.

Description:
BACKGROUND OF THE DISCLOSURE 
     This patent application is a continuation-in-part of co-pending patent application Ser. No. 374,450 entitled Diphase Drain Cleaner, now U.S. Pat. No. 4,453,983. 
    
    
     Sulfuric acid has been used to clear drains of many organic materials, including fats, hair, paper, cotton, tea, coffee grounds and tobacco, as well as some inorganic materials such as chalk, hard water salts, lime scale and iron scales. The properties of sulfuric acid which make it effective for drain cleaning include: (1) its high heat of dilution in contact with residual water in the drain which melts fats, greases and low melting point compounds that otherwise act as clogging sites for other debris; (2) its reactivity with a wide range of function groups such as hydroxyl, carbonyls, esters, unsaturated bonds, rings and amino groups; and (3) its high dissociation constant that helps dissolve many organic and inorganic materials. Notable examples of use of sulfuric acid to clean drains are U.S. Pat. Nos. 3,538,008 to Ancel et al. and 4,096,871 to Vlahakis. 
     Unfortunately, sulfuric acid will not affect polystyrene. Consequently, it is desirable to combine sulfuric acid with a polystyrene solvent in a single drain cleaning drain cleaning system. However, many polystyrene solvents are reactive with sulfuric acid and they have not previously been employed together in a stable two-phase drain cleaning composition. 
     Previous drain cleaning compositions and processes that utilize hydrocarbon solvents include U.S. Pat. Nos. 3,553,145 and 3,553,146 to Butke et al., 3,666,670 to Gilbert et al., 3,576,751 to Noznick et al., and 3,060,125 to Sims. None of the disclosed compositions use halogenated hydrocarbon solvents specifically for dissolution of polystyrene. 
     The Diphase Drain Cleaner patent application identified above was primarily directed to halogenated aromatic hydrocarbon polystyrene solvents. The present application is, in comparison, directed to halogenated aliphatic hydrocarbon polystyrene solvents. 
     It is an object of the present invention to provide an improved two layer composition for diphase cleaning of a drain utilizing selected halogenated aliphatic polystyrene solvent. 
     It is another object of the present invention to provide a method of cleaning a drain using a diphase composition of sulfuric acid and selected halogenated aliphatic polystyrene solvents. 
    
    
     DESCRIPTION OF THE INVENTION 
     I have discovered that certain organic solvents and solvent blends will not be attacked by sulfuric acid. These solvents form a layer above sulfuric acid and dissolve polystyrene while not being affected by, or having an affect upon sulfuric acid. A stable diphase composition is formed. Further, the two layers produce a synergistic effect. The heat produced by the sulfuric acid reacting with water present in the drain drastically increases the polystyrene dissolving powers of the solvent layer. The solvent layer also acts to wash down the sides of the drain as the drain blockage is removed and to act as a &#34;cover&#34; for unwanted smells from sulfuric acid reaction products. 
     The composition of the invention consists of two mutually immiscible liquid layers. The lower and denser layer makes up from 50 to 99 percent of the total composition weight and consists of at least 20 percent sulfuric acid solution. The preferred composition uses 93 percent sulfuric acid solution for the lower layer. 
     The sulfuric acid solution should be of sufficient concentration and volume to make a sulfuric acid solution of at least 10% concentration after dilution with water in the drain. Normally, about four ounces of water will sit above a clogged drain. Therefore, a minimum amount of four ounces of at least 25% sulfuric acid solution is required. Of course, less volume of a more concentrated solution would be necessary. 
     The upper less-dense layer makes up from 1 to 50 percent of the total composition weight and consists of selected halogenated aliphatic hydrocarbon polystyrene solvents such as carbon tetrachloride; dichloroethane; trichloroethane; trichloroethylene; dichloropropane; tetrachloroethane; pentachloroethane; and perchloroethylene. The invention contemplates the upper layer composed of any of these substances or a combination of two or more of the substances. 
     The upper less-dense layer may include saturated aliphatic hydrocarbons to reduce the necessary amount of halogenated aliphatic hydrocarbon in that layer. Substances such as mineral oil and mineral spirits, containing saturated cyclic hydrocarbons, are adequate for this purpose. The upper layer can be up to 99% by weight saturated hydrocarbons, being up to almost 5% of the total composition weight. At least 1% by weight of the upper layer should be any of the halogenated aliphatic hydrocarbons listed above or any combination thereof. That is, the active ingredients in the upper layer are the halogenated aliphatic hydrocarbons which should make up at least 0.01% of the total composition weight. 
     A preferred composition consists of a lower layer being 95% of total composition weight and consisting of 93% sulfuric acid solution. A solvent blend makes up the upper layer, being 5% of the total composition weight. The solvent blend is composed of equal amounts of weight of the halogenated aliphatic hydrocarbon and the saturated aliphatic hydrocarbons. Alternatively, the solvent blend may vary from 95% by weight saturated hydrocarbons and 5% by weight halogenated aliphatic, to 100% by weight halogenated aliphatics. 
     The particular polystyrene solvents used in the upper layer blend were selected because of two criteria: (1) they must be stable in contact with concentrated sulfuric acid; and (2) they must be effective polystyrene solvents when in a layer above concentrated sulfuric acid. In order to determine which solvents meet these criteria, stability and effectiveness studies were conducted. 
     STABILITY STUDY 
     The following results were obtained for storage of five cubic centimeters of a candidate solvent in a layer above and in contact with ninety/five cubic centimeters of concentrated sulfuric acid (93%) at room temperature in glass containers. 
     
         ______________________________________5 cc Solvent Over 95 cc 93% Sulfuric AcidSolvent            Observation______________________________________methyl ethyl ketone              Layer gone in 1 day.chlorothene NU.sup.(1)              Reacts releasing sulfur              dioxide.pinene             Layer gone in 1 day.dipentene          Layer gone in 1 day.ethyl benzoate     Layer gone in 7 days.methyl benzoate    Layer gone in 7 days.ethyl proprionate  Layer gone in 7 days.sodium xylene sulfonate              Forms gel in 7 days.isopropyl alcohol  Layer gone in 7 days.ethyl alcohol      Layer gone in 7 days.octyl alcohol      Layer gone in 14 days.toluene            Layer gone in 26 days.xylene             Layer gone in 26 days.paraxylene         Layer 1/3 gone in 26              days.mesitylene         Forms crystals in              sulfuric acid in 7              days.methylene chloride Layer gone in 31 days.orthochlorotoluene Layer remains over 90              days.Freon 113.sup.(2)  Layer remains over 90              days.perchloroethylene  Layer remains over 90              days.orthodichlorobenzene              Layer remains over 90              days.a blend of orthodichloro-              Layer remains over 90benzene and paradichloro-              days.benzene (1:1)carbon tetrachloride              Layer remains over 90              days.1,2 dichloroethane Layer remains over 90              days.1,1,1 trichloroethane              Layer remains over 90              days.1,1,2 trichloroethylene              Layer remains over 90              days.1,2 dichloropropane              Layer remains over 90              days.1,1,2 trichloroethane              Layer remains over 90              days.1,1,2,2 tetrachloroethane              Layer remains over 90              days.1,1,1,2,2 pentachloroethane              Layer remains over 90              days.trichloromonofluoromethane              Layer remains over 90              days.Mineral Spirits    Layer essentially              unchanged over 90              days; sulfuric              significantly              darkened.140 Solvent.sup.(3)              Layer essentially              unchanged over 90              days; sulfuric              significantly              darkened.OB #140.sup.(3)    Layer essentially              unchanged over 90              days; sulfuric              significantly              darkened.Odorless Mineral Spirits.sup.(3)              Layer essentially              unchanged over 90              days; sulfuric              significantly              darkened.135 Solvent.sup.(3)              Layer essentially              unchanged over 90              days; sulfuric              significantly              darkened.Odorless Base #3.sup.(3)              Layer essentially              unchanged over 90              days; sulfuric              significantly              darkened.Alkylate 21.sup.(4)              Layer essentially              unchanged over 30              days; sulfuric              darkened.Alkylate 200.sup.(5)              Layer essentially              unchanged over 30              days; sulfuric              darkened.Alkylate 300.sup.(5)               Layer essentially              unchanged over 30              days; sulfuric              darkened.Isopar E.sup.(6)   Layer essentially              unchanged over 90              days; sulfuric              darkened.Isopar M.sup.(6)   Layer essentially              unchanged over 30              days; sulfuric              darkened.DC 200, 100 cs..sup.(7)              Essentially unchanged              over 90 days.Kaydol.sup.(8)     Essentially unchanged              over 90 days;              sulfuric slightly              darkened.Klearol.sup.(8)    Essentially unchanged              over 90 days;              sulfuric slightly              darkened.______________________________________ .sup.(1) Dow Chemical Co. principally 1,1,1trichloroethane plus significant amounts of inhibitors. .sup.(2) E. I. DuPont De Nemours, Inc.,  trichlorotrifluoroethane .sup.(3) Technical Petroleum Co. .sup.(4) Chevron Chem. Co.  monoalkyl benzene .sup.(5) Chevron Chem. Co.  mono and dialkyl benzene .sup.(6) Exxon Oil  isoparaffinic hydrocarbon .sup.(7) Dow Chem. Co.  dimethyl siloxane .sup.(8) Witco Co.  refined mineral oil 
    
     Additional stability data was obtained for storage of five cubic centimeters of the candidate solvent in a layer above and in contact with ninety-five cubic centimeters of 84% sulfuric acid solution at 100° F. in glass containers. The results are set forth below. 
     
         ______________________________________5 cc Solvent in 95 cc 84% SulphuricAcid Stored at 100° F.Solvent         Observations______________________________________toluene         Layer reduced 50% in 26           days; sulfuric           slightly yellow.xylene          Layer reduced 50% in 26           days; sulfuric very           slightly yellow.paraxylene      Layer reduced 25% in 26           days.Alkylate 21     Layer essentially           unchanged in 26 days.Alkylate 300    Layer essentially           unchanged except for           color.______________________________________ 
    
     EFFECTIVENESS STUDY 
     The study of the effectiveness of candidate solvents in a layer above sulfuric acid for dissolving polystyrene was conducted using the following procedure: 
     (1) A Pyrex measuring cup was placed on an acid resistant surface; 
     (2) An empty polystyrene drinking cup was placed in the center of the Pyrex container; 
     (3) The following items were placed in the polystyrene cup: 
     a paper towel 
     a teaspoon of Crisco 
     a piece of Kotex 
     a tea bag 
     a cigarette or cigarette butt; 
     (4) The polystyrene cup was filled about half way with water; and 
     (5) The solvent-acid system was added to the contents of the polystyrene cup. 
     The results of these tests are summarized below: 
     
         ______________________________________Effectiveness Study       wt. %  Observations______________________________________Test 1sulfuric acid, 93%         95.00    Breaks through cup in 2OB 140        4.75     minutes. Cup rapidlyorthochlorotoluene         .25      dissolves in mixture.         100.00Test 2sulfuric acid, 93%         95.00    Stays in cupOB 140        5.00     overnight. No apparent         100.00   actionTest 3sulfuric acid, 93%         95.00    Stays in cupOB 140        4.95     overnight. There isorthochlorotoluene         .05      slight attack on cup         100.00   but no enough to break                  through.Test 4sulfuric acid, 93%         95.00    Breaks through cup inxylene        5.00     less than 2 minutes.         100.00   Cup rapidly dissolves                  in mixture.Text 5sulfuric acid, 93%         95.00    Breaks through cup intoluene       5.00     less than 2 minutes.         100.00   Cup rapidly dissolves                  in mixture.Test 6sulfuric acid, 93%         95.00    Breaks through cup inorthochlorotoluene         5.00     less than 2 minutes.         100.00   Cup rapidly dissolves                  in mixture.Test 7sulfuric acid, 93%         95.00    Stays in cupkerosene      5.00     overnight. No apparent         100.00   action.Test 8sulfuric acid, 84%         95.00    Breaks through cup in 2OB 140        4.75     minutes. Cup rapidlyorthochlorotoluene         .25      dissolves in mixture.         100.00Test 9sulfuric acid, 93%         95.00    Breaks through cup in 2orthodichloro-         5.00     minutes. Cup rapidlybenzene                dissolves in mixture.         100.00Test 10sulfuric acid, 93%         95.00    Breaks through cup in 2OB 140        2.50     minutes. Cup rapidlyorthodichloro-         2.50     dissolves in mixture.benzene         100.00Test 11sulfuric acid, 93%         95.00    Stays in cupOB 140        4.75     overnight. There isorthodichloro-         .25      slight attack on cupbenzene                but not enough to break         100.00   through.Test 12sulfuric acid, 93%         95.00    Breaks through cup inOB 140        2.50     2 minutes. Cupcarbon tetrachloride         2.50     dissolves in mixture.         100.00Test 13sulfuric acid, 93%         95.00    Breaks through cup inOB 140        2.50     2 minutes. Cup1,2 dichloroethane         2.50     dissolves in mixture.         100.00Test 14sulfuric acid, 93%         95.00    Breaks through cup inOB 140        2.50     2 minutes. Cup1,1,1 trichloroethane,         2.50     dissolves in mixture.uninhibited         100.00Test 15sulfuric acid, 93%         95.00    Breaks through cup inOB 140        2.50     2 minutes. Cup1,1,2 trichloro-         2.50     dissolves in mixture.ethylene         100.00Test 16sulfuric acid, 93%         95.00    Breaks through cup inperchloroethylene         2.50     2 minutes. CupOB 140        2.50     dissolves in mixture.         100.00Test 17sulfuric acid, 93%         90.00    Breaks through cup inOB 140        5.00     2 minutes. Cuporthodichloro-         5.00     dissolves in mixture.benzene         100.00Test 18sulfuric acid, 93%         95.00    Breaks through cup inOB 140        2.50     2 minutes. Cup1,2 dichloropropane         2.50     dissolves in mixture         100.00Test 19sulfuric acid, 93%         95.00    Breaks through cup inOB 140        2.50     2 minutes. Cup1,1,2 trichloro-         2.50     dissolves in mixture.ethane         100.00Test 20sulfuric acid, 93%         95.00    Cup breaks through in 2OB 140        2.50     minutes. Cup dissolves1,1,2,2 tetra-         2.50     in mixture.chloroethane         100.00Test 21sulfuric acid, 93%         95.00    Cup breaks through in 2pentachloroethane         2.50     minutes. Cup dissolvesOB 140        2.50     in mixture.         100.00Test 22sulfuric acid, 93%         95.00    Cup breaks through in 2OB 140        4.50     minutes, but the cuphexachloroethane         .50      does not dissolve in         100.00   mixture.Test 23sulfuric acid, 93%         95.00    The cup breaks throughOB 140        2.50     but the Freontrichloromonofluoro-         2.50     solublizes before themethan                 cup dissolves.         100.00______________________________________ 
    
     Additional ingredients such as a corrosion inhibitor, dye or stable fragrance may be added to make the composition more commercially desirable. 
     Drains are cleaned by the diphase composition in a unique manner. The denser sulfuric acid layer comes in contact with water and the drain blockage. It melts and dissolves fats, hair, paper, cotton, tea, coffee grounds and tobacco, chalk, hard water salts, lime scale, iron salts, and other organic and inorganic substances which may cause drain blockage. Polystyrene material in the drain blockage is not affected by the sulfuric acid but will be released from the drain blockage as the other substances are melted and dissolved. The free polystyrene will float to the upper less-dense layer of halogenated aliphatic hydrocarbons where it is dissolved. Although the density of the sulfuric acid solution will vary with its strength, it will normally be denser than the halogenated aliphatic layer and will, consequently, be the lower layer in the composition. This guarantees initial contact of the sulfuric acid with the drain blockage. 
     The following examples demonstrate possible diphase drain cleaning compositions. 
     EXAMPLE I 
     95% by weight 93% sulfuric acid is combined with 5% by weight carbon tetrachloride to produce a two layer composition. 
     EXAMPLE II 
     60% by weight 40% sulfuric acid is combined with 20% by weight of 1,1,1-trichloroethane and 20% by weight of saturated aliphatic hydrocarbons to form a two layer composition for cleaning drains. 
     EXAMPLE III 
     50% by weight 80% sulfuric acid is combined with 49.75% by weight saturated aliphatic hydrocarbons and 0.25% by weight pentachloroethane to produce a diphase drain cleaning composition. 
     While the invention presently disclosed is considered to be the preferred embodiment of the invention, it is understood that changes, modifications and substitutions may be made therein without departing from the true scope of the invention as defined in the claims.