ADDITIVES TO STABILIZE POLYACRYLAMIDE CO-POLYMER SOLUTIONS UNDER HIGH SHEAR CONDITIONS

Abstract

Described herein are compositions and methods for stabilizing the ability of hydrated polyacrylamide co-polymers to modify the physical properties of water solutions under high shear conditions. The compositions generally include a water solution including at least one hydrated polyacrylamide co-polymer; and at least one additive selected from the group consisting of i) a component having the formula of Formula 1, where Formula 1 is R.sub.1—O-EO.sub.a-PO.sub.b-EO.sub.c—PO.sub.d—R.sub.2, where R.sub.1 is hydrogen or any C.sub.1 to C.sub.18 carbon or carbon chain; O is oxygen, EO.sub.a is —(CH.sub.2CH.sub.2—O).sub.a where a can be from 0-500; PO.sub.b is —(CH(CH.sub.3)CH.sub.2—O).sub.b where b can be from 0-70; EO.sub.c is —(CH.sub.2CH.sub.2—O).sub.c where c can be from 0-150; PO.sub.d is —CH(CH.sub.3)CH.sub.2—O).sub.d where d is from 0-30; and R.sub.2 is hydrogen or any C.sub.1 to C.sub.18 carbon or carbon chain; ii) a tetra functional block copolymer; iii) a polyvinylpyrrolidone (PVP) homopolymer; and iv) any combination thereof.

Claims

1. A composition comprising: A) a hydrated polyacrylamide homopolymer or co-polymer; B) at least one additive selected from the group consisting of: i) a component having an average calculated molecular weight between 350-22,000 and having the formula
R.sub.1—O-EO.sub.a—PO.sub.b-EO.sub.c-PO.sub.d—R.sub.2   (Formula 1) wherein R.sub.1 is hydrogen or any C.sub.1 to C.sub.18 carbon chain; O is oxygen, EO.sub.a is —(CH.sub.2CH.sub.2—O).sub.a wherein a can be from 0-500; PO.sub.b is —(CH(CH.sub.3)CH.sub.2—O).sub.b wherein b can be from 0-70; EO.sub.c is (CH.sub.2CH.sub.2—O).sub.c wherein c can be from 0-150; PO.sub.d is CH(CH.sub.3)CH.sub.2—O).sub.d wherein d is from 0-30; and R.sub.2 is hydrogen or any C.sub.1 to C.sub.18 carbon chain; ii) a tetra functional block copolymer; iii) a polyvinylpyrrolidone (PVP) homopolymer; and iv) any combination thereof; and C) a water solution.

2. The composition of claim 1, wherein the average calculated molecular weight of Formula 1 is between 400-8,000.

3. The composition of claim 1, wherein the average calculated molecular weight of the tetra functional block copolymer is between 4,000-30,000.

4. The composition of claim 1, wherein the average calculated molecular weight of the tetra functional block copolymer is between 1,000-8,000.

5. The composition of claim 1, wherein the molecular weight of the PVP homopolymer is between 2,000-180,000.

6. The composition of claim 1, wherein the water solution contains at least one agrochemical component.

7. The composition of claim 6, wherein the agrochemical component is a pesticide.

8. The composition of claim 1, wherein the at least one additive is included in an amount from 0.01% to 40% by weight based on the total weight of the composition.

9. The composition of claim 1, wherein more than one additive is included.

10. A method of forming a composition for reducing the effects of shear on a hydrated polyacrylamide homopolymer or co-polymer comprising the step of combining at least one A component, at least one B component, and at least one C component of claim 1.

11. A method for reducing the effects of shear on a hydrated polyacrylamide co-polymer comprising the step of forming the composition of claim 1 by combining at least one A component, at least one B component, and at least one C component of the additive with a water solution containing a hydrated polyacrylamide homopolymer or co-polymer.

12. The method of claim 11, wherein a droplet size distribution is maintained or increases at a slower rate upon application of shear in compositions that include an additive of the disclosure.

13. A method for stabilizing the interaction of the long strands of a hydrated polyacrylamide homopolymer or co-polymer in a water solution subjected to shear conditions comprising the step of forming the composition of claim 1 by combining at least one A component, at least one B component, and at least one C component of claim 1.

14. The method of claim 13, wherein the stabilized interaction of the long strands of the hydrated polyacrylamide homopolymer or co-polymer are demonstrated by a slower rate of increasing droplet size distribution.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0030] The following drawings form part of the present specification and are included to further demonstrate certain aspects of the present disclosure. The disclosure may be better understood by reference to one or more of these drawings in combination with the detailed description of specific embodiments presented herein.

[0031] FIG. 1 is a schematic drawing of a pump system used for testing compositions of the present disclosure. The system was designed to provide 40 psi back pressure to a 5 inch centrifugal pump (note the holding tank is not represented in the diagram). The apparatus uses a long length of tubing to provide sliding friction that creates the back pressure of 40 psi on the pump without the added shear of the nozzle. The output is 1 gallon per minute out of the end of the hose and 2 gallons per minute bypass (recycle). The only nozzle involved in the shear is the nozzle atomizing for sizing in the spray cabinet (a TeeJet XR8002VS or TeeJet TTI11004 (TeeJet ® Technologies, Glendale Heights, Ill.));

[0032] FIG. 2 is a graph illustrating the results of Example 1 which demonstrates the effect of 3 different polyethylene glycol products having average molecular weights of 400 (“Shear Additive 1” or “SA1”), 1450 (“Shear Additive 2” or “SA2”), and 8000 (“Shear Additive 3” or “SA3”) at a 0.25% inclusion level with a 1.7% v/v solution of a 48.7% potassium glyphosphate herbicide formulation (“PS1”) such as the pesticide solution ROUNDUP POWERMAX® (Bayer Crop Science, Research Triangle Park, N.C. (formerly Monsanto, St. Louis, Mo.)) and with or without 2 different hydrated polyacrylamide co-polymers, 1) 50 ppm of a co-polymer comprised of acrylamide monomer, AMPS (2-Acrylamido-2-Methylpropane sulfonic acid) monomer and a hydrophobic monomer as described in CA 2892689A1 (BASF SE) (“Polymer C” or “CP1”), and 2) 50 ppm of a high molecular weight nonionic polyacrylamide (“CP2”) when cycled multiple times through the pump system of FIG. 1 and subsequently sprayed through the XR8002VS (TeeJet Technologies) nozzle for droplet analysis;

[0033] FIG. 3 is a graph illustrating the results of Example 2, which demonstrates the effect of 3 different polypropylene glycol products, SA4, SAS, and SA6 at 2 different inclusion levels (0.25% for SA4 and SA5, 0.05% for SA6) with the pesticide solution PSI and with the CP1 co-polymer when cycled multiple times through the pump system of FIG. 1 and subsequently sprayed through the XR8002VS (TeeJet Technologies) nozzle for droplet analysis;

[0034] FIG. 4 is a graph illustrating the results of Example 3 which demonstrates the effect of 3 different ethylene oxide propylene oxide block co-polymer products, SA7, SA8, and SA9 at a 0.25% inclusion level with the PS1 pesticide solution and with or without the CP2 hydrated polyacrylamide co-polymer when cycled multiple times through the pump system of FIG. 1 and subsequently sprayed through the XR8002VS (TeeJet Technologies) nozzle for droplet analysis;

[0035] FIG. 5 is a graph illustrating the results of Example 4 which demonstrates the effect of 3 different Methoxy Polyethylene Glycols, SA10, SA11, and SA12, at a 0.25% inclusion level with the PS1 pesticide solution and with or without 50 ppm of a copolymer of acrylamide monomer and AMPS (2-Acrylamide-2-Methylpropane sulfonic Acid) monomer (“CP3”) at 1 concentration when cycled multiple times through the pump system of FIG. 1 and subsequently sprayed through the TTI11004 nozzle (TeeJet Technologies) for droplet analysis;

[0036] FIG. 6 is a graph illustrating the results of Example 5 which demonstrates the effect of 5 different Alcohol Alkoxylates, SA13, SA14, SA15, SA16, and SA17 at a 0.25% inclusion level with the PS1 pesticide solution and with or without the hydrated polyacrylamide co-polymer Polymer CP1 at 1 concentration when cycled multiple times through the pump system of FIG. 1 and subsequently sprayed through the XR8002VS (TeeJet Technologies) nozzle for droplet analysis;

[0037] FIG. 7 is a graph illustrating the results of Example 6 which demonstrates the effect of 2 different TETRONIC® additives (BASF Corporation), TETRONIC® 304 and TETRONIC® 1301 at a 0.25% inclusion level with the PSI pesticide solution and with or without the hydrated polyacrylamide co-polymer CP1 at a concentration of 0.625% when cycled multiple times through the pump system of FIG. 1 and subsequently sprayed through the XR8002VS (TeeJet Technologies) nozzle for droplet analysis.

[0038] FIG. 8 is a series of graphs, 8a and 8b, illustrating the results of Example 7 which demonstrates the effect of 3 different vinyl pyrrolidone homopolymer products, SA18, SA19, and SA20, at a 0.02% inclusion level with the PS1, pesticide solution 2 (“PS2”), which is a 1.1% v/v solution of a 42.8% diglycol amine salt of dicamba herbicide formulation such as XTENDIMAX® with VAPORGRIP® TECHONOLOGY (Bayer Crop Science, Research Triangle Park, N.C. (formerly Monsanto, St. Louis, Mo.)), or combination of PS1 and PS2 pesticide solutions and with or without the hydrated polyacrylamide co-polymer Polymer CP1 or CP3 at 2 concentrations when cycled multiple times through the pump system of Protocol 2 of FIG. 1 and subsequently sprayed through the TTI11004 nozzle (TeeJet Technologies) for droplet analysis.

DETAILED DESCRIPTION

[0039] The following detailed description and examples set forth preferred materials and procedures used in accordance with the present disclosure. It is to be understood, however, that this description and these examples are provided by way of illustration only, and nothing therein shall be deemed to be a limitation upon the overall scope of the present disclosure.

EXAMPLE 1

Materials and Methods

[0040] This example tests the effect of 3 different products, Shear Additive 1 (SA1), Shear Additive 2 (SA2), and Shear Additive 3 (SA3) at a 0.25% inclusion level with the pesticide solution PS1 and with or without 2 different hydrated polyacrylamide co-polymers, CP1 and CP2 when cycled multiple times through the pump system of FIG. 1 and subsequently sprayed through the XR8002VS (TeeJet Technologies) nozzle for droplet analysis. The parameters and results of this example are provided below in Table 1 and in FIG. 2.

TABLE-US-00001 TABLE 1 Conc. Starting Pump Final Additive Conc. Polymer PPM Pesticide Conc. Nozzle psi % V < 141 μ Passes V % < 141 μ ΔV % None — None — PS1 1.70% XR8002VS 45 55 10 55 0 None — CP1 50 PS1 1.70% XR8002VS 45 22 10 43 21 None — CP2 50 PS1 1.70% XR8002VS 45 13 10 41 28 SA1 0.25% CP2 50 PS1 1.70% XR8002VS 45 9 10 22 13 SA1 0.25% CP1 50 P51 1.70% XR8002VS 45 14 10 29 15 SA1 0.25% CP1 50 P51 1.70% XR8002VS 45 9 10 22 13 —(CH2CH2—O).sub.a —(CH(CH3)CH2—O).sub.b —(CH2CH2—O).sub.c —(CH(CH3)CH2—O).sub.d R1—O EO a PO b EO c PO d —R2 R1 a = b = c = d = R2 ave MW method SA1 H 9 0 0 0 H  400 calculated SA2 H 33 0 0 0 H 1450 calculated SA3 H 182 0 0 0 H 8000 calculated

Results

[0041] As shown by the data, compositions incorporating CP1 experienced a 21% change in droplet size after 10 passes through the pump system when no additive was included compared to a 15% change and a 13% change when 0.25% of SA2 or SA3 , respectively, was included. Similarly, compositions incorporating CP2 experienced a 28% change in droplet size with no additive and only a 13% change when 0.25% of SA1 was included. FIG. 2 illustrates that the compositions containing an additive experienced less variation in droplet size as evidenced by the lower percentage of droplets that had a volume less than 141 μm at each successive pass through the pump system. Droplet size of the pesticide solution alone (with no additives) was unaffected by the shear conditions.

EXAMPLE 2

Materials and Methods

[0042] This example demonstrates the effect of 3 different products, SA4, SAS, and SA6 at 2 different inclusion levels (0.25% for SA4 and SA5, 0.05% for SA6) with the pesticide solution PS1 and with the CP1 co-polymer when cycled multiple times through the pump system of FIG. 1 and subsequently sprayed through the XR8002VS (TeeJet Technologies) nozzle for droplet analysis. The parameters and results of this example are provided below in Table 2 and in FIG. 3.

TABLE-US-00002 TABLE 2 Final Shear Conc. Starting Pump V % < Additive Conc. Polymer PPM Pesticide Nozzle psi % V < 141 μ Passes 141 μ ΔV % None — None — PS 1 XR8002VS 45 55 10 55 0 None — CP 1 50 PS 1 XR8002VS 45 22 10 43 21 SA 4 0.25% CP 1 50 PS 1 XR8002VS 45 8 10 16 8 SA 5 0.25% CP 1 80 PS 1 XR8002VS 45 7 5 25 18 SA 6 0.05% CP 1 50 PS 1 XR8002VS 45 12 3 38 26 —(CH2CH2—O).sub.a —(CH(CH3)CH2—O).sub.b —(CH2CH2—O).sub.c —(CH(CH3)CH2—O).sub.d —R2 Polypropylene R1—O EO a PO b EO c PO d ave Glycols R1 a = b = c = d = R2 MW method SA 4 H 0 7 0 0 H  425 calculated SA 5 H 0 17 0 0 H 1000 calculated SA 6 H 0 35 0 0 H 2000 calculated

Results

[0043] As shown by the data and FIG. 3, compositions incorporating CP1 experienced a 21% change in droplet size after 10 passes through the pump system when no additive was included compared to an 8% change when 0.25% of SA4 was included. When the concentration of CP1 was increased to 1%, there was still just an 18% change after 5 pump passes. When the concentration of SA6 was decreased to 0.05%, there was just a 26% change after 3 pump passes. FIG. 3 also illustrates that the compositions containing an additive experienced less variation in droplet size as evidenced by the lower percentage of droplets that had a volume less than 141 μm at each successive pass through the pump system. Droplet size of the pesticide solution alone was unaffected by the shear conditions.

EXAMPLE 3

Materials and Methods

[0044] This example tests the effects of 3 different products, SA7, SA8, and SA9 at a 0.25% inclusion level with the PS 1 and with the CP1 hydrated polyacrylamide co-polymers when cycled multiple times through the pump system of FIG. 1 and subsequently sprayed through the XR8002VS (TeeJet Technologies) nozzle for droplet analysis. The parameters and results of this example are provided below in Table 3 and in FIG. 4.

TABLE-US-00003 TABLE 3 Shear Conc. Starting Pump Final Additive Conc. Polymer PPM Pesticide Nozzle psi % V < 141 μ Passes V % < 141 μ ΔV % None — None — PS 1 XR8002VS 45 55 10 55 0 None — CP 2 50 PS 1 XR8002VS 45 13 10 45 28 SA 7 0.25% CP 2 50 PS 1 XR8002VS 45 10 10 31 21 SA 8 0.25% CP 2 50 PS 1 XR8002VS 45 9 10 28 19 SA 9 0.25% CP 2 50 PS 1 XR8002VS 45 14 10 41 27 EO/PO —(CH2CH2—0).sub.a —(CH(CH3)CH2—O).sub.b —(CH2CH2—O).sub.c —(CH(CH3)CH2—O).sub.d Block R1—O EO a PO b EO c PO d —R2 ave Polymers R1 a = b = c = d = R2 MW method SA 7 H 11 16 11 0 H 1900 calculated SA 8 H 6.5 22 6.5 0 H 1850 calculated SA 9 H 133 50 133 0 H 14600 calculated

Results

[0045] As shown by the data and FIG. 4, compositions incorporating Polymer CP2 experienced a 28% change in droplet size after 10 passes through the pump system when no additive was included compared to a 21%, 19%, and 27% change when 0.25% of SA7, SA8, or SA9, respectively was included. FIG. 4 illustrates that the compositions containing an additive experienced less variation in droplet size as evidenced by the lower percentage of droplets that had a volume less than 141 μm at each successive pass through the pump system. Droplet size of the PS1 pesticide solution alone was unaffected by the shear conditions.

EXAMPLE 4

Materials and Methods

[0046] This example demonstrates the effect of 3 different Methoxy Polyethylene Glycols, SA10, SA11, and SA12, at a 0.25% inclusion level with the PS1 pesticide solution and with or without a copolymer of acrylamide monomer and AMPS (2-Acrylamide-2-Methylpropane sulfonic Acid) monomer (“CP3”) at 1 concentration when cycled multiple times through the pump system of FIG. 1 and subsequently sprayed through the TTI1104XR8002VS (TeeJet Technologies) nozzle for droplet analysis. The parameters and results of this example are provided below in Table 4 and in FIG. 5.

TABLE-US-00004 TABLE 4 Shear Conc. Starting Pump Final Additive Conc. Polymer PPM Pesticide Nozzle psi % V < 141 μ Passes V % < 141 μ ΔV % None — None — PS 1 TTI 11004 63 2.25 3 2.25 0 None — CP 3 50 PS 1 TTI 11004 63 1.83 3 2.01 0.18 SA 10 0.25% CP 3 50 PS 1 TTI 11004 63 2.18 3 2.16 −0.02 SA 11 0.25% CP 3 50 PS 1 TTI 11004 63 2.09 3 1.29 −0.8 SA 12 0.25% CP 3 50 PS 1 TTI 11004 63 1.72 3 1.79 0.07 Methoxy —(CH2CH2—O).sub.a —(CH(CH3)CH2—O).sub.b —(CH2CH2—O).sub.c —(CH(CH3)CH2—O).sub.d Polyethylene R1—O EO a PO b EO c PO d R2 ave Glycols R1 a = b = c = d = —R2 MW method SA 10 CH3 11 0 0 0 H 550 calculated SA 11 CH3 7 0 0 0 H 350 calculated SA 12 CH3 5 0 0 0 H 250 calculated

Results

[0047] As shown by the data and FIG. 5, compositions incorporating CP3 experienced a 0.18% change in droplet size after 3 passes through the pump system with no additive and a −0.02%, −0.8%, and 0.07% change when 0.25% of SA10, SA11, and SA12, respectively was included. FIG. 5 also illustrates that the compositions containing an additive experienced less variation in droplet size as evidenced by the lower percentage of droplets that had a volume less than 141 μm at each successive pass through the pump system. Droplet size of the PS1 pesticide solution alone was unaffected by the shear conditions.

EXAMPLE 5

Materials and Methods

[0048] This example tests the effects of 5 different Alcohol Alkoxylates, SA13, SA14, SA15, SA16, and SA17, at a 0.25% inclusion level with the PS1 pesticide solution and with or without the CP1 co-polymer when cycled through the pump system of FIG. 1 and subsequently sprayed through the XR8002VS (TeeJet Technologies) nozzle for droplet analysis. The parameters and results of this example are provided in Table 5 and FIG. 6.

TABLE-US-00005 TABLE 5 Shear Conc. Starting Pump Final Additive Conc. Polymer PPM Pesticide Nozzle psi % V < 141 μ Passes V % < 141 μ ΔV % None — None — PS 1 XR8002VS 45 55 10 55 0 None — CP 1 50 PS 1 XR8002VS 45 22 10 43 21 SA 13 0.25% CP 1 50 PS 1 XR8002VS 45 10 3 31 21 SA 14 0.25% CP 1 50 PS 1 XR8002VS 45 12 3 31 19 SA 15 0.25% CP 1 50 PS 1 XR8002VS 45 7 3 24 17 SA 16 0.25% CP 1 50 PS 1 XR8002VS 45 7 3 19 12 SA 17 0.25% CP 1 50 PS 1 XR8002VS 45 7 3 16 9 —(CH2CH2—O).sub.a —(CH(CH3)CH2—O).sub.b —(CH2CH2—O).sub.c —(CH(CH3)CH2—O).sub.d Alcohol R1—O EO a PO b EO c PO d —R2 ave Alkoxylates R1 a = b = c = d = R2 MW method SA 13 C6C10 0 3 17.8 7.5 H 1500 calculated SA 14 C10 5.7 4.7 2.3 0 H 773 calculated SA 15 C10 5.7 4.7 0.3 0 H 685 calculated SA 16 C12C15 9.9 4.9 0 0 H 917 calculated SA 17 C13C15 12 6 0 0 H 1078 calculated

Results

[0049] As shown by the data and FIG. 6, compositions incorporating CP1 experienced a 21% change in droplet size after 10 passes through the pump system with no additive and a 21%, 19%, 17%, 12%, and 9% change when 0.25% of SA13, SA14, SA15, SA16, and SA17, respectively, was included. FIG. 6 also illustrates that the compositions containing an additive experienced less variation in droplet size as evidenced by the lower percentage of droplets that had a volume less than 141 μm at each successive pass through the pump system. Droplet size of the PS1 pesticide solution alone was unaffected by the shear conditions.

EXAMPLE 6

Materials and Methods

[0050] This example tests the effects of 2 different tetra functional block copolymers at a 0.25% inclusion level with the PS1 pesticide solution and with or without the hydrated polyacrylamide co-polymer CP1 at 1 concentration when cycled multiple times through the pump system of FIG. 1 and subsequently sprayed through the XR8002VS (TeeJet Technologies) nozzle for droplet analysis. The parameters and results of this example are provided below in Table 6 and in FIG. 7.

TABLE-US-00006 TABLE 6 Shear Conc. Starting Pump Final Additive Conc. Polymer PPM Pesticide Nozzle psi % V < 141 μ Passes V % < 141 μ ΔV % None — None — PS 1 XR8002VS 45 55 10 55 0 None — CP 1 50 PS 1 XR8002VS 45 22 10 43 21 Tetronic ® 0.25% CP 1 50 PS 1 XR8002VS 45 10 3 22 12 304 Tetronic ® 0.25% CP 1 50 PS 1 XR8002VS 45 12 3 32 20 1301

Results

[0051] As shown by the data and FIG. 7, compositions incorporating CP1 experienced a 21% change in droplet size after 10 passes through the pump system with no additive and a 12% and 20% change when 0.25% of Tetronic 304 or Tetronic 1301 (BASF Corporation), respectively, was included. FIG. 7 further illustrates that the compositions containing an additive experienced less variation in droplet size as evidenced by the lower percentage of droplets that had a volume less than 141 μm at each successive pass through the pump system. Droplet size of the PS1 pesticide solution alone was unaffected by the shear conditions.

EXAMPLE 7

Materials and Methods

[0052] This example tests the effect of 3 different vinyl pyrrolidone products, SA18, SA19, and SA20, having average molecular weights of 17,000, 30,000, and 90,000, respectively, at a 0.020% inclusion level with PS1, PS2, or a combination of PS1 and PS2 pesticide solution and with or without the hydrated polyacrylamide co-polymer Polymer CP1 or CP3 at a 0.625% concentration or at a concentration of 80% when cycled multiple times through the pump system of FIG. 1 and subsequently sprayed through the TTI11004 (TeeJet Technologies) nozzle for droplet analysis. The parameters and results of this example are provided below in Table 7 and in FIGS. 8a and 8b.

TABLE-US-00007 TABLE 7 Shear Conc. Starting Pump Final Additive Conc. Polymer PPM Pesticide Nozzle psi % V < 141 μ Passes V % < 141 μ ΔV % None — None — PS 2 TTI11004 63 2.36 10 2.36 0 None — CP 1 — PS 2 + PS 1 TTI11004 63 2.01 10 3.19 1.18 SA 18 0.020% CP 1 80 PS 2 + PS 1 TTI11004 63 1.24 10 2.08 0.84 SA 19 0.020% CP 1 80 PS 2 + PS 1 TTI11004 63 1.32 10 1.64 0.32 None — None — PS 2 TTI11004 63 2.62 10 2.62 0 None — CP 3 50 PS 2 + PS 1 TTI11004 63 1.97 10 3.25 1.28 SA 19 0.020% CP 3 80 PS 2 + PS 1 TTI11004 63 1.44 5 1.91 0.47 SA 20 0.020% CP 3 80 PS 2 + PS 1 TTI11004 63 1.27 5 2.50 1.23 Polymers ave MW SA 18 vinyl pyrrolidone homopolymer 17,000 SA 19 vinyl pyrrolidone homopolymer 30,000 SA 20 vinyl pyrrolidone homopolymer 90,000

Results

[0053] As shown by the data, compositions incorporating Polymer CP1 experienced a 1.18% change in droplet size after 10 passes through the pump system with no additive and a 0.84% and 0.32% change when 0.020% of SA18 or SA19, respectively, was added. Polymer CP3 experienced a 1.28% change in droplet size after 10 passes through the pump system of FIG. 1 with no additive and a 0.47% and 1.23% change when SA19 and SA20, respectively, was added. FIGS. 8a and 8b illustrate that the compositions containing an additive experienced less variation in droplet size as evidenced by the lower percentage of droplets that had a volume less than 141 μm at each successive pass through the pump system. Droplet size of the pesticide solution alone was unaffected by the shear conditions.

Discussion

[0054] The data demonstrate that inclusion of at least one additive of the present disclosure has a surprising effect on the stability of a high molecular weight polyacrylamide co-polymer in a water solution. The stability is evidenced by a comparison of the droplet size during multiple passes through a pump system that subjects the water solution to high shear conditions. The at least one additive can have the formula of Formula 1, R.sub.1-O-EO.sub.a—PO.sub.b-EO.sub.c—PO.sub.d—R.sub.2 wherein R.sub.1 is hydrogen or any C.sub.1 to C.sub.18 carbon or carbon chain; O is oxygen, EO.sub.a is —(CH.sub.2CH.sub.2—O).sub.a where a can be from 0-500; PO.sub.b is —(CH(CH.sub.3)CH.sub.2—O).sub.b where b can be from 0-70; EO.sub.c is —(CH.sub.2CH.sub.2—O), where c can be from 0-150; PO.sub.d is —CH(CH.sub.3)CH.sub.2—O).sub.d where d is from 0-30; and R.sub.2 is hydrogen or any C.sub.1 to C.sub.18 carbon or carbon chain. The at least one additive can also be a tetra functional block co-polymer. Preferably, the tetra functional block co-polymer is based on ethylene oxide and propylene oxide. The at least one additive can also be a polyvinylpyrrolidone homopolymer (hereinafter “PVP”). Finally, the additive can comprise any combination of the additives described above. In other words, the additive can comprise one or more additives individually and respectively selected from the additives described above. For example, the additive can comprise one or more additives having the formula of Formula 1, one or more tetra functional block co-polymers, and/or one or more PVP additives. Further, the additive can comprise at least one additive of Formula 1, and/or at least one tetra functional block co-polymer, and/or at least one PVP additive.

[0055] As shown by the data, the droplet size of the pesticide solution alone was not affected by the shear conditions. However, the droplet size of the solutions that did not include at least one additive were adversely effected as each cycle through the pump system resulted in greater change in droplet size than solutions that did include at least one additive as described herein.