Patent Grant
9090516
A novel solvent-free formulation system has been discovered that is capable of enhancing the application, stability, and performance of nitrogen fertilizer stabilizing compositions that are based on n-alkyl thiophosphoric triamides. The existing art that deals with the formulation of n-alkyl thiophosphoric triamides for agricultural applications is based on the use of traditional organic solvents that have a number of limitations related to cold weather stability, toxicity, fertilizer compatibility, cost, and clean-up. The new approach that we have discovered eliminates or significantly reduces these problems and is capable of providing a liquid formulation without the use of solvents.
N-alkyl thiophosphoric triamides (particularly n-butyl phosphorotriamide) (NBPT) are used extensively in applications with urea based fertilizers due to their ability to inhibit the urease enzyme. The urease enzyme is ubiquitous to most soils—and is responsible for the conversion of urea nitrogen to volatile ammonia gas. This volatile form of nitrogen is lost from the soil, thus reducing the amount that is available for plants. The ability of n-alkyl thiophosphoric triamides to provide this inhibition makes for a valuable tool in management of nitrogen fertilizer applications.
An object of the invention was to find a composition that eliminates or significantly reduces the problems discussed above and is capable of providing a liquid formulation without the use of solvents.
Another object of the invention is to find a formulation that can be used in a fertilizer that does not contain any ingredients that can be carcinogenic, such as the liquid amides, such as the ones described in U.S. Pat. No. 5,698,003 such as 2-pyrrolidone or N-alkyl 2-pyrrolidones.
Surface active agents (surfactants) are used extensively for their ability to improve the ability of water based mixtures to cover and/or adhere to a range of surfaces. We have surprisingly found that a number of surfactants may be used to produce stable liquid n-alkyl thiophosphoric triamide compositions without the use of solvents. While the exact mechanism for this conversion of dry n-alkyl thiophosphoric triamide to a liquid form with surfactants is unknown, we have been able to utilize this phenomenon to produce a number of formulations that reduce or eliminate the limitations of traditional solvent based n-alkyl thiophosphoric triamide formulations.
The invention relates to a composition comprising a solvent free liquid concentrate of at least one N-alkyl thiophosphoric triamide in at least one surfactant selected from the group consisting of:
As used herein, all percentages are on a weight basis unless otherwise stated herein or otherwise obvious herefrom to one skilled in the art.
The invention relates to a composition comprising a solvent free liquid concentrate of at least one N-alkyl thiophosphoric triamide in at least one surfactant surfactant selected from the following group:
The N-alkyl thiophosphoric triamide is preferably a C2-C10 alkyl and most preferably C4 alkyl (NBPT). The concentration of N-alkyl thiophosphoric triamide ranges from preferably 1.0 to 60.0 wt. % based on the total composition, more preferably from 10 to 30% and even more preferably about 20 wt. %.
Examples of some preferred surfactant categories that can be used in these compositions include cationic, non-ionic, anionic and amphoteric surfactants. More specific types of preferred surfactants include non-ionic linear or branched alcohol ethoxylate surfactants, anionic phosphoric acid ester surfactants (sometimes referred to as “phosphate ester” surfactants), and cationic ethoxylated tallow amine surfactants. The at least one surfactant selected from the groups consisting of
Useful surfactants include but are not limited to:
Other surfactants as disclosed in McCutcheon's Emulsifiers and Detergents, North American Edition, 2000.
Other surfactants as disclosed in 1 the following patents:
A preferred surfactant is alcohol alkoxylates—both linear and branched. The alcohol preferably contains 2 to 20 carbons atoms, preferably 4 to 12 carbons and most preferably 9-11 carbon atoms. The alkoxylate is 2 to 20 moles added to the alcohol and most preferably 3-10 moles. Both propylene and ethylene oxide are used for the alkoyxlation.
Glycols and glycol derivatives described in U.S. Pat. No. 5,698,003 are not included in the surfactants for this invention.
Other adjuvants commonly used in agricultural compositions include compatibilizing agents, antifoam agents, sequestering agents, neutralizing agents and buffers, corrosion inhibitors, dyes, odorants, spreading agents, penetration aids, sticking agents, dispersing agents, thickening agents, freezing point depressants, antimicrobial agents, stabilizers and the like.
Dyes can be in an amount from 0.1 to 0.5 wt %.
Stablizers can be but are not limited to organic acids. Examples of organic acids include but are not limited to citric acid, benzoic acid, acidic acid, salicylic acid, lactic acid, succinic acid, and oxalic acid. Stabilizers can be present in an amount from 0.1 to 1.0 wt. % preferably from 0.1 to 0.2 wt. %.
Antifoam agents can include 2-ethyl hexanol or polydimethylsiloxane. Antifoaming agents can be present in an amount from 0.005 to 0.5 wt. %, preferably from 0.05 to 0.1 wt. %.
Examples of the composition are listed below:
The invention also includes using the composition in a urea based fertilizer. The composition can be mixed with a liquid or dry fertilizer. A nitrogen stabilizing rate—can range from 0.001 to 0.1000% of the fertilizer.
The application of the liquid or dry fertilizer treated to soil, water, or other media that is used for the purposes of growing plants.
The application of the composition can be used as a method to improve the efficacy of nitrogen stabilization provided by an application N-alkyl thiophosphoric triamide treated fertilizer to soil, water, or other media used for the purposes of growing plants. In particular, the application of the composition according to the invention can be used in a process to improve the efficacy of nitrogen stabilization provided by an application N-alkyl thiophosphoric triamide treated fertilizer to soil, water, or other media used for the purposes of growing plants which comprises utilizing the inventive composition.
These solutions can be stored over extended periods of time and can conveniently serve as a vehicle to impregnate the N-alkyl thiophosphoric triamide onto urea based solid fertilizers using a variety of fertilizer bulk blending equipment commonly available with fertilizer dealers and distributors. Any suitable or conventional equipment can be used to apply the formulation to the solid fertilizer. Preferably the addition provides a thorough impregnation of the solid fertilizers by the formulation. The fact that these above mentioned formulations are universally miscible with the typical liquid urea containing fertilizers also makes these formulations extremely useful for these applications. Any suitable or conventional equipment can be used to incorporate the formulation into the liquid fertilizer.
The application of the composition according to the invention can be used as a means of reducing the toxicity of n-alkyl thiophosphoric triamide formulations. In particular, the invention is also directed to a process for reducing the toxicity of n-alkyl thiophosphoric triamide formulations which comprises adding at least one surfactant to n-alkyl thiophosphoric triamide wherein said at least one surfactant is selected from the group consisting of:
The application of the composition according to the invention can be used as a means of improving the cold temperature stability of n-alkyl thiophosphoric triamide formulations, In particular the invention is directed to a process for improving the cold temperature stability of n-alkyl thiophosphoric triamide formulations which comprises adding at least one surfactant to n-alkyl thiophosphoric triamide wherein said at least one surfactant is selected from the group consisting of:
The application of the according to the invention can be used as a means of improving the clean out of containers and equipment used to store and apply n-alkyl thiophosphoric triamide formulations. In particular, the application of the composition according to the invention can be used in a process for improving the clean out of containers or equipment used to store and apply n-alkyl thiophosphoric triamide formulations which comprises contacting the containers or equipment with the inventive composition.
All the references described above are incorporated by reference in their entirety for all useful purposes.
This application claims the benefit of U.S. Provisional Application 61/683,857 filed on Aug. 16, 2012 and U.S. Provisional Application 61/703,518 filed on Sep. 20, 2012 which are both incorporated by reference in its entirety.
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| Number | Date | Country | |
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| 61683857 | Aug 2012 | US | |
| 61703518 | Sep 2012 | US |
