Abstract:
A stable wetting concentrate includes octyl or dodecyl pyrrolidone, an ethoxylated alcohol, and a compatabilizing agent for dilution of the concentrate with water, suitably a polar material, such as an anionic emulsifier, or polyol, which prevents separation of the two base components in water, and, optionally, water, provides a stable wetting composition upon dilution with water, which exhibit superior wetting and spreading properties.

Description:
BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     This invention relates to wetting agents, and, more particularly, to a stable wetting concentrate, and aqueous wetting compositions thereof, which exhibit superior wetting and spreading properties. 
     2. Description of the Prior Art 
     Kolazi S. Narayanan, in U.S. Pat. Nos. 5,424,072; 5,508,249; 5,470,508; and U.S. Pat. No. 5,409,639; has described the use of N-octyl pyrrolidone (Surfadone® LP 100) (International Specialty Products) in several applications, particularly for agricultural chemicals. N-octyl pyrrolidone (NOP) however, is costly compared to other surfactants. 
     Accordingly, it is an object of this invention to provide a stable, superior wetting agent with NOP at a reduced cost. 
     SUMMARY OF THE INVENTION 
     What is described herein is a wetting concentrate comprising, by wt.,
         (a) 10-30% of an octyl or dodecyl pyrrolidone,   (b) 50-90% of an ethoxylated alcohol, e.g. ethoxylated noninol,   (c) 0.5-5% of a compatabilizer for (a) and (b) upon dilution with water, e.g. an anionic emulsifier, or polyol, and   (d) 0-10% water.       

     In the preferred forms of the invention, (b) contains 2 or 3 EO units, the weight ratio of (a):(b) is about 80:20, (c) is sodium lauryl sulfate or sodium laureth sulfate, and (c) is about 2.5%. and (d) is about 1.5%. 
     A stable wetting composition includes the wettable concentrate and water of dilution, wherein the water of dilution, in parts concentrate to water of is 1:50 to 1:5000, preferably 1:1000 to 1:2000. 
     A typical use wetting formulation herein includes the wetting concentrate and water of dilution, which is useful, e.g. as an agricultural spray solution, a surface cleanser, a car wash or a fountain wash. 
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     N-octyl pyrrolidone (Agsol® Ex 8 or Surfadone® LP 100) is used commercially in several applications, either neat or in conjunction with other formulated compositions. The main advantage of N-octyl pyrrolidone is its high solvency for hydrophobic molecules. It can also form mixed micelles with several other surfactants, especially with anionic emulsifiers such as sodium lauryl sulfate (SLS) and sodium laureth sulfate. N-octyl pyrrolidone is unique in also being a surface active solvent and thus it can function as an interfacial solvent. This property is advantageous in many consumer formulations e.g. to control the release of organic fragrances and to provide additional wetting on surfaces in spray solutions. 
     The wetting concentrate of the invention includes (a) octyl or dodecyl pyrrolidone, (b) an ethoxylated alcohol, e.g. ethoxylated nonyl alcohol, (c) is a compatabilizer, preferably an anionic emulsifier, or polyol, and, optionally (d) water. 
     Preferably, in the wetting concentrate, (b) contains 2 or 3 EO units; the weight ratio of (a):(b) is about 80:20; and (c) is sodium lauryl sulfate or sodium laureth sulfate. 
     A stable wetting composition of the invention comprises the wetting concentrate and water of dilution, wherein the water of dilution ratio of concentrate to water is about 1:50 to 1:5000; preferably about 1:1000 to 1:2000. 
     Typical use formulations of the invention includes the wetting concentrate in an agricultural spray solution, a surface cleanser, a car wash or a fountain wash. 
     Use formulations of the invention can have wetting times &lt;30 sec. and a spreading area on Parafilm® surfaces (hydrophobic surface) 6.25×that of water (20 microliter). 
     EXAMPLES 
     Materials Used 
     
         
         
           
             Sodium Laureth Sulfate, 2 EO, Purity 25.6%, Rhodapex® ES-2 [Rhodia Chemicals, NJ]. 
             Sodium Laureth Sulfate, 3 EO, Purity 30%, Standapol® ES-3 [Stepan Chemicals, NJ]. 
             Sodium Lauryl Sulfate 29% aqueous solution, [Rhodia]. 
             N-(n-Octyl)-2-Pyrrolidone, Water, Purity &gt;99.0%, Agsol® Ex 8 [International Specialty Products, Wayne, NJ]. 
             Poly-(Oxy-1,2-ethanedlyl)-alpha-undecyl-omega 1-undecanol, 1-undecanol, (ethoxylated nonyl alcohol). Purity 84%. Tomadol® 1-3 [Tomah Reserve, Inc., Reserve, LA].
 
A) Preparation of Wetting Concentrates and Aqueous Diluted Solutions Thereof of Solutions and Serial Dilutions.
 
           
         
       
    
     The wetting concentrates were prepared by weighing accurately the appropriate amounts of each ingredient to produce 100 g of stock solutions. 
     Table 1 below shows the invention ternary compositions containing Agsol® Ex 8, Tomodol® 1-3, aqueous sodium laureth sulfate 2 EO, and/or aqueous sodium laureth sulfate 3 EO. These compositions were prepared by adding increasing amounts (from 0-25%) of commercially available aqueous sodium laureth sulfate to the base mixture of Agsol® Ex 8 and Tomidol® 1-3 (20:80). 
     
       
         
               
               
             
               
               
               
               
               
             
               
               
               
               
               
             
           
               
                   
                 TABLE 1 
               
             
             
               
                   
                   
               
               
                   
                 Wetting Concentrates 
               
             
          
           
               
                 Ingredient 
                 1 [SW 1] 
                 2 [SW 2] 
                 3 (SW 3) 
                 4 (SW 4) 
               
               
                   
               
             
          
           
               
                 Agsol Ex 8 
                 20 
                 19 
                 18.83 
                 19.0 
               
               
                 Tomadol 1-3 
                 80 
                 76 
                 75.31 
                 76.0 
               
               
                 SLS (29%) 
                 0 
                 5 
                 0 
                 0 
               
               
                 Rhodapex ES-2, 
                 0 
                 0 
                 5.86 
               
               
                 25.6% 
               
               
                 Standapol ES-3, 
                 0 
                 0 
                 0 
                 5.0 
               
               
                 30% 
               
               
                 Total 
                 100 
                 100 
                 100 
                 100 
               
               
                 Agsol Ex 8 
                 20 
                 19 
                 18.73 
                 19.0 
               
               
                 Tomadol 1-3 
                 80 
                 76 
                 75.31 
                 76.0 
               
               
                 SLS (Solid) 
                 0 
                 1.5 
                 0 
                 0 
               
               
                 Rhodapex ES-2 
                 0 
                 0 
                 1.50 
                 0 
               
               
                 Standapol ES-3 
                 0 
                 0 
                 0 
                 1.50 
               
               
                 Water 
                 0 
                 3.5 
                 4.46 
                 3.50 
               
               
                 Total 
                 100 
                 100 
                 100 
                 100 
               
               
                   
               
             
          
         
       
     
     These stock solutions were used to prepare for serial dilutions as follows. SW 1 diluted with distilled water.
         1) 1/100,10 g of Agsol EX 8 was diluted to 1000 g.   2) 1/500,100 g of Solution 1) was diluted to 500 g.   3) 1/1000, 50 g of Solution 1) was diluted to 500 g.   4) 1/2000, 25 g of Solution 1) was diluted to 500 g.   5) 1/5000, 50 g of Solution 2) was diluted to 500 g.       

     Similarly, the rest of the stock solutions at dilutions: 1/100,1/1000, 1/2000, and 1,5000 were prepared as above. All diluted solutions were used for the following tests.
     B) Stability/separation on standing   C) Drave&#39;s wetting time   D) Spreading/area of droplets/area ratios   E) Foam properties
 
B) Stability/Separation on Standing
   

     50 ml of each diluted solution was transferred to a Nessler color comparison tube and each solution was observed from time zero to 10 days. The results are shown in Table 2 below. 
     C) Wetting Time (Drave&#39;s Method) 
     About 300 ml of each dilution (higher dilution first) was transferred into a 250 ml volumetric cylinder. The weight was Hooked on to a cotton skein, then transferred into the cylinder slowly with weight at the lower end. Once the weight was placed at the bottom of the cylinder, a stop watch was started immediately, and the position of cotton skein was observed. The time was recorded when the cotton skein fell to the bottom of the cylinder. This procedure was repeated several times and an average of the wetting time for each solution was recorded. Typically reproducibility was within 10% of reported values, as shown in Table 3. The aqueous solutions of Agsol Ex 8 were acidified with conc HCI to pH ˜1.2 to solubilize Agsol Ex 8. In all other compositions using Agsol Ex 8, no acid was added. 
     D) Spreading Efficacy 
     A fine-mm graph paper was inserted between two 12 inch×12 inch glass plates. 20 microliter of each solution was transferred on a para-film wax paper mounted on the glass plate. The time and diameter of each drop was immediately recorded by observing it through a magnifying glass with ˜20× magnification. The diameter of the same drop was again measured after three minutes. This procedure was repeated at least three times for each drop. The average diameter after three minutes was recorded. Similarly the average diameter of a drop of distilled water was recorded after three minutes. The ratio of the square of the radius of each set of droplets and the radius of a water droplet was calculated as a measure of spreading efficacy, as shown in Table 4. 
     E) Foam 
     A 50 ml solution was accurately transferred into a 100 ml-measuring cylinder, stoppered, and the solution was inverted at a 180° angle 25 times. The volume height of the foam was recorded for fifteen minutes from time zero to a 1-minute interval and the foam volume height was recorded. This procedure then was repeated and an average of two readings for each minute was recorded in mm length. Similarly foam heights of all diluted stock solutions were measured (see Table 5 relative foam heights for compositions 6 and 7 or SW 1 and SW 2). 
     Table 2 shows the physical stability of selected compositions of Table 1 upon dilution with at ratios of 1/100, 1/500, 1/1000, and 1/2000. All compositions remained clear even after 10 days. However, on dilution in water, the base composition not containing any anionic surfactant (SW 1) separated into two phases within 24 h at 1/100 dilution. However, addition of 5% aqueous sodium laureth sulfate (either with 2 EO or with 3 EO) was sufficient to improve its stability on dilution. 
     The wetting, spreading and foaming properties of the blends of Agsol® Ex 8, Tomadol® 1-3 and aq Rhodapex® ES-2, or, and Standapol® ES-3, at dilutions at 1/100, 1/500, 1/1000, 1/2000, and 1/5000 were determined. The results are shown in Tables 3 through Tables 5. 
     
       
         
               
             
               
               
               
               
               
             
               
               
               
               
               
             
           
               
                 TABLE 2 
               
             
             
               
                   
               
               
                 Stability of Diluted Compositions of Invention at Room Temperature 
               
             
          
           
               
                   
                 1 (SW 1) 
                 2 (SW 2) 
                 3 (SW 3) 
                 4 (SW 4) 
               
               
                   
                   
               
             
          
           
               
                 Time, Zero 
                   
                   
                   
                   
               
               
                 Dilution 
               
               
                 1/100 
                 Cloudy, phase 
                 Cloudy, no 
                 Cloudy 
                 Cloudy 
               
               
                   
                 separation 
                 separation 
                 phase 
                 phase 
               
               
                   
                 with time 
                 after 7 days 
               
               
                 1/500 
                 Thin emulsion 
                 Cloudy, 
                 Thin 
                 Thin 
               
               
                   
                 separation 
                 2 mm 
                 emulsion 
                 emulsion 
               
               
                   
                 with time 
                 cream after 
               
               
                   
                   
                 one week 
               
               
                 1/1000 
                 Thin emulsion, 
                 Thin 
                 Clear 
                 Thin 
               
               
                   
                 separation 
                 emulsion, no 
                   
                 emulsion 
               
               
                   
                 with time 
                 separation 
               
               
                   
                   
                 in 20 days 
               
               
                 1/2000 
                 Thin emulsion, 
                 Clear 
                 Clear 
                 Clear 
               
               
                   
                 separation 
               
               
                   
                 with time 
               
               
                 1/5000 
                 Clear 
                 Clear 
                 Clear 
                 Clear 
               
               
                 24 hrs 
               
               
                 1/100 
                 Two phases, 
                 Cloudy, no 
                 Cloudy 
                 Cloudy 
               
               
                   
                 150 mm top 
                 separation in 
                 phase 
                 phase 
               
               
                   
                 clears in 10 
                 7 days 
               
               
                   
                 inversions, 
               
               
                   
                 Reappears 
               
               
                   
                 in 3–4 hrs 
               
               
                 1/500 
                 Thin emulsion, 
                 Cloudy, 2 
                 Thin 
                 Thin 
               
               
                   
                 separation 
                 mm cream 
                 emulsion 
                 emulsion 
               
               
                   
                 with time 
                 after one 
               
               
                   
                   
                 Week 
               
               
                 1/1000 
                 Thin emulsion, 
                 Thin 
                 Clear 
                 Clear 
               
               
                   
                 separation 
                 emulsion, no 
               
               
                   
                 with time 
                 separation 
               
               
                   
                   
                 in 20 days 
               
               
                 1/2000 
                 Thin emulsion, 
                 Clear 
                 Clear 
                 Clear 
               
               
                   
                 separation 
               
               
                   
                 with time 
               
               
                 1/5000 
                 Clear 
                 Clear 
                 Clear 
                 Clear 
               
               
                 10 days 
               
               
                 1/100 
                 Two 
                 30 mm 
                 Cloudy 
                 Cloudy 
               
               
                   
                 phases, 
                 cream on 
                 phase, 
                 phase, 
               
               
                   
                 100 mm 
                 top, 
                 thin 
                 thin 
               
               
                   
                 cream, 
                 reversible, 
                 emulsion 
                 emulsion 
               
               
                   
                 clears in 10 
                 clears in 10 
               
               
                   
                 inversions, 
                 inversions, 
               
               
                   
                 Reappears 
                 reappears 
               
               
                   
                 after 
                 after 
               
               
                   
                 3–4 hrs 
                 24 hrs 
               
               
                 1/500 
                 Two 
                 5 mm 
                 Clear 
                 Thin 
               
               
                   
                 phases, 
                 cream on 
                   
                 emulsion 
               
               
                   
                 10 mm 
                 top after 
               
               
                   
                 cream 
                 one week 
               
               
                   
                 on top 
               
               
                 1/1000 
                 Two 
                 Clear to 
                 Clear 
                 Clear 
               
               
                   
                 phases, 
                 cloudy, 
               
               
                   
                 5 mm 
                 2 mm 
               
               
                   
                 cream on 
                 cream 
               
               
                   
                 top 
                 after 20 
               
               
                   
                   
                 days 
               
               
                 1/2000 
                 Two 
                 2 mm 
                 Clear 
                 Clear 
               
               
                   
                 phases, 
                 cream 
               
               
                   
                 2 mm 
                 after 20 
               
               
                   
                 cream on 
                 days 
               
               
                   
                 top 
               
               
                 1/5000 
                 Clear 
                 Clear 
                 Clear 
                 Clear 
               
               
                   
               
             
          
         
       
     
     
       
         
               
             
               
               
               
               
               
             
               
               
             
               
               
               
               
               
             
               
               
             
               
               
               
               
               
             
           
               
                 TABLE 3 
               
             
             
               
                   
               
               
                 Wetting Properties of Compositions of Invention 
               
             
          
           
               
                   
                 1 [SW 1] 
                 2 [SW 2] 
                 3 (SW 3) 
                 4 (SW 4) 
               
               
                   
                   
               
             
          
           
               
                   
                 Concentrate 
               
               
                   
                 % Composition 
               
               
                   
                   
               
             
          
           
               
                 Agsol Ex 8 
                 20 
                 19 
                 18.83 
                 19.0 
               
               
                 Tomadol 1-3 
                 80 
                 76 
                 75.31 
                 76.0 
               
               
                 SLS (29%) 
                 0 
                 5 
                 0 
                 0 
               
               
                 Aq. Rhodapex 
                 0 
                 0 
                 5.86 
                 0 
               
               
                 ES-2, 25.6% 
               
               
                 Aq. Standapol 
                 0 
                 0 
                 0 
                 5.0 
               
               
                 ES-3, 30% 
               
               
                   
               
             
          
           
               
                   
                 Aqueous Use Formulation 
               
               
                 Dilution Ratio 
                 Wetting Time, sec 
               
               
                   
               
             
          
           
               
                 1/100 
                 1 
                 1 
                 1–3 
                 1–3 
               
               
                 1/500 
                 3 
                 2 
                 3 
                 3 
               
               
                 1/1000 
                 9 
                 6 
                 10 
                 10 
               
               
                 1/2000 
                 22 
                 24 
                 20 
                 23 
               
               
                   
               
             
          
         
       
     
     
       
         
               
             
               
               
               
               
               
             
           
               
                 TABLE 4 
               
             
             
               
                   
               
               
                 Spreading Properties* 
               
             
          
           
               
                 Dilution Ratio 
                 1 (SW 1) 
                 2 (SW 2) 
                 3 (SW 3) 
                 8 (SW 4) 
               
               
                   
               
               
                 1/100 
                 5.49 
                 5.49 
                 5.49 
                 5.88 
               
               
                 1/500 
                 5.49 
                 5.49 
                 5.88 
                 5.88 
               
               
                 1/1000 
                 5.49 
                 5.13 
                 4.42 
                 4.67 
               
               
                 1/2000 
                 4.67 
                 5.13 
                 4.42 
                 5.13 
               
               
                 1/5000 
                 4.67 
                 5.13 
                 4.09 
                 4.09 
               
               
                   
               
               
                 *Water system- Spreading data: Spreading droplet area ratio on paraffin-area ratio of 20 microliter droplet on Parafilm compared to water 
               
             
          
         
       
     
     
       
         
               
             
               
               
               
               
               
             
               
               
               
               
               
             
           
               
                 TABLE 5 
               
             
             
               
                   
               
               
                 Foam Height, mm on Dilution of Concentrates 
               
             
          
           
               
                   
                 1 (SW 1) 
                 2 (SW 2) 
                 3 (SW 3) 
                 8 (SW 4) 
               
               
                   
                   
               
             
          
           
               
                 Formulation 
                   
                   
                   
                   
               
               
                 Agsol Ex 8 
                 20 
                 19 
                 18.83 
                 19 
               
               
                 Tomadol 1-3 
                 80 
                 76 
                 75.31 
                 76 
               
               
                 SLS (29%) 
                 0 
                 5 
                 0 
                 0 
               
               
                 Rhodapex ES-2, 
                 0 
                 0 
                 5.86 
                 0 
               
               
                 25.6% 
               
               
                 Standapol ES-3, 30% 
                 0 
                 0 
                 0 
                 5 
               
               
                 Total 
                 100 
                 100 
                 100 
                 100 
               
               
                   
               
               
                   
                 after 1 min 
                 2 min 
                 3 min 
                 5 min 
               
               
                   
               
               
                 SW 1 — Dilution 
               
               
                 in deionized water 
               
               
                 1/100 
                 67 
                 57 
                 38 
                 19 
               
               
                 1/500 
                 44 
                 29 
                 19 
                 13 
               
               
                 1/1000 
                 48 
                 46 
                 46 
                 46 
               
               
                 1/2000 
                 42 
                 36 
                 29 
                 23 
               
               
                 1/5000 
                 27 
                 27 
                 23 
                 19 
               
               
                 SW 2 — Dilution 
               
               
                 in deionized water 
               
               
                 1/100 
                 67 
                 67 
                 65 
                 61 
               
               
                 1/500 
                 67 
                 65 
                 65 
                 61 
               
               
                 1/1000 
                 57 
                 51 
                 51 
                 49 
               
               
                 1/2000 
                 57 
                 49 
                 38 
                 38 
               
               
                 1/5000 
                 48 
                 34 
                 32 
                 28 
               
               
                 SW 3 — Dilution 
               
               
                 in deionized water 
               
               
                 1/100 
                 66 
                 66 
                 65 
                 65 
               
               
                 1/500 
                 66 
                 66 
                 65 
                 65 
               
               
                 1/1000 
                 66 
                 66 
                 63 
                 61 
               
               
                 1/2000 
                 47 
                 47 
                 45 
                 45 
               
               
                 1/5000 
                 42 
                 42 
                 40 
                 40 
               
               
                 SW 4 — Dilution 
               
               
                 in deionized water 
               
               
                 1/100 
                 61 
                 61 
                 61 
                 61 
               
               
                 1/500 
                 32 
                 32 
                 61 
                 59 
               
               
                 1/1000 
                 28 
                 28 
                 53 
                 51 
               
               
                 1/2000 
                 47 
                 47 
                 47 
                 45 
               
               
                 1/5000 
                 40 
                 40 
                 40 
                 40 
               
               
                   
               
             
          
         
       
     
     Ternary blends of (N-octyl or N-dodecyl pyrrolidone), ethoxylated noninol with 2 EO and 3 EO and aqueous sodium lauryl sulfate or sodium laureth sulfate exhibited excellent properties of clarity, wetting, spreading, and foam on dilution with water. Superior wetting (cotton) and spreading on Parafilm® surfaces were observed with the blends. The most favorable clarity was observed for ternary blends, i.e. in the presence of an anionic emulsifier e.g. sodium laureth or sodium lauryl sulfates. The inventive compositions find application where wetting and spreading on hydrophobic surfaces is necessary, e.g. tank mix additives in agricultural formulations, and additives in cleaning compositions. Ternary blends with sodium laureth sulfate showed properties comparable to ternary blends with aqueous sodium lauryl sulfate; however sodium laureth sulfate is particularly advantageous for personal care products because of lower skin irritation of sodium laureth sulfate compared to sodium lauryl sulfate. 
     While the invention has been described with particular reference to certain embodiments thereof, it will be understood that changes and modifications may be made which are within the skill of the art. Accordingly, it is intended to be bound only by the following claims, in which: