Patent Application
20160249607
The present invention relates to a liquid composition comprising a high concentration of a non-ionic water-soluble polysaccharide ether, a polyol having 3-4 hydroxyl groups, water and at least one salt of a polyvalent inorganic anion. The invention also relates to agricultural formulations obtainable by adding an agriculturally active ingredient and such a liquid composition to water, and to methods for treating a plant with such an agricultural formulation.
Polysaccharide ethers are known as additives in agricultural formulations. Various cellulose ethers have been suggested for use in agricultural formulations, for example as sticking agents and deposition aids, and guar gum has been proposed as a drift reducing agent.
U.S. Pat. No. 6,534,563 relates to the use of polymers as sticking agents in aqueous agricultural formulations, and teaches the use of ethyl hydroxyethyl cellulose with a Mw of ˜105 g/mol.
WO 2012/080196 relates to the use of hydrophobically modified polysaccharide ethers, such as hydrophobically modified methyl ethyl hydroxyethyl cellulose as deposition aids in agricultural formulations.
WO 99/012869 relates to the use of guar gum as a drift reducing agent in an aqueous agricultural formulation.
The concentration of the polysaccharide ethers in the agricultural formulations is generally very low, in the order of 0.005-0.5 wt %, and in order to obtain the desired effect from the polysaccharide ethers, it is important that the polysaccharide ether is evenly distributed in the agricultural formulation. Further, as the agricultural formulation is generally sprayed onto the crops, it is important that it is free of lumps and big undissolved particles to prevent clogging of the spraying nozzles.
The most common form of polysaccharide ethers, such as cellulose ethers, is as a powder. However, dissolving such a powder in water is inconvenient both for the time needed, as it has to be dissolved little by little, and the problems that can occur. The most severe problem is the formation of so called “fish eyes”, i.e. agglomerated polysaccharide ether particles that has been swollen in the corona but not in the core. Such fish eyes are very hard to dissolve on short time scales, since mass transport of water into these particles is very slow.
It would be convenient to have a form of polysaccharide ethers that is of relatively high concentration, yet easy to dilute without giving rise to the problems connected with fish eye formation.
US2002/10121224 relates to a suspension of water-soluble, non-ionic cellulose ethers with low viscosity. However, the long term stability of such suspensions may be limited, and the relatively high quantities of salt are not very attractive in some applications.
Therefore, it remains a need in the art to provide a highly concentrated polysaccharide ether composition that can be easily diluted in water, and that has a long shelf life, and wherein the polysaccharide ether from such composition, when added to an agricultural formulation, gives the desired properties to the agricultural formulation.
One object of the present invention is to provide a liquid polysaccharide ether containing composition that at least partially meets the need in the art.
Another object of the invention is to provide an agricultural formulation that exhibit inter alia desired anti-drift properties, deposition properties and/or rainfastness properties.
It has now surprisingly been found that these objects can be met by a liquid composition comprising a high concentration of a non-ionic water-soluble polysaccharide ether, a polyol having 3-4 hydroxyl groups, water and at least one salt of a multivalent inorganic anion.
The composition of the invention, which can contain from 2 to 30 wt %, based on the total weight of the composition, of a non-ionic, water-soluble polysaccharide ether, is a low viscous liquid at room temperature and can easily and quickly be diluted in water to low concentrations, such as from 0.005 to 0.5 wt % of the polysaccharide ether, without the need for vigorous stirring, and without any significant formation of fish-eyes.
The composition of the invention further exhibits long term stability (shelf-life) and resistance to freeze-thawing cycles without irreversibly forming agglomerates.
The agricultural formulation formed by adding the composition of the invention and at least one agriculturally active agent to water is given the desired properties from the polysaccharide ether.
The invention will now be described more in detail.
In a first aspect, the present invention relates to a liquid composition comprising
a) 2 to 30, preferably 2 to 25, more preferably 5 to 20, most preferably 8 to 16 wt %, based on the total weight of the liquid composition, of a non-ionic water-soluble polysaccharide ether;
b) 55 to 90, preferably 60 to 85, more preferably 65 to 80 wt %, based on the total weight of the liquid composition, of a polyol having 3 to 4 hydroxyl groups;
c) 5 to 25, preferably 6 to 20, more preferably 7 to 15 wt %, based on the total weight of the liquid composition, of water; and
d) 0.1 to 5, preferably 0.3 to 4, more preferably 0.5 to 3 wt %, based on the total weight of the liquid composition, of at least one salt of a multivalent inorganic anion.
The non-ionic water-soluble polysaccharide ether suitable for use in the present invention may be linear or branched, and is preferably a cellulose ether or guar gum ether.
Cellulose ethers suitable for use in the present invention may have a turbidity point (flocculation temperature) from 25° C. to 100° C. measured in a 1% by weight aqueous solution, but polysaccharide ethers having a turbidity point of above 100° C. may also be used. Preferably, the cellulose ether has a turbidity point of 30° C. to 80° C. The viscosity (hereinafter the “1% viscosity”) is normally between 5 and 15,000 mPa*s measured at 1 wt % concentration in water at pH=7 with a Brookfield viscosimeter, type LV, at 12 rpm at 20° C. (Spindle No 2 is used for measuring viscosities up to 3,500 mPa*s, and Spindle No 3 is used for measuring viscosities above 3,500 mPa*s). Cellulose ethers having a viscosity of 7,000 mPa*s or higher, such as 8,000 mPa*s or higher may be advantageous.
The DSalkyl of the cellulose ether may be 0 or from 0.1 to 2.5, preferably from 0.2 to 2.0, more preferably from 0.3 to 1.3, wherein the alkyl has 1-4 carbon atoms. The DSalkyl, which refers to the lower alkyl groups having 1-4 carbon atoms, is adapted to the hydrophobicity of these alkyl groups, which means that DS is normally lower for the more hydrophobic groups propyl and butyl than it is for methyl and ethyl. DSmethyl is suitably 0.3-2.5, preferably 0.5-2.0, and most preferably 0.7-1.9. DSethyl is suitably 0.1-1.5, preferably 0.3-1.2, and most preferably 0.5-1.0.
The MShydroxyalkyl of the cellulose ether may be 0 or from 0.2 to 4.0, suitably 1.0-3.0, and preferably 1.5-2.8, wherein the hydroxyalkyl is hydroxyethyl, hydroxypropyl and/or hydroxybutyl. The MShydroxyethyl is also normally within this general range. The MShydroxypropyl is normally within a range of 0.1-2.0, suitably 0.2-1.7, and preferably 0.3-1.5. If hydroxybutyl groups are present, the MShydroxybutyl is normally<0.5.
The MShydrophobe of the cellulose ether may be 0 or from 0.001 to 0.02, wherein the hydrophobe is a hydrocarbyl group having from 10 to 18 carbon atoms. When the polysaccharide ether is hydrophobically modified, the product typically has a MShydrophobe of 0.001 or more, preferably 0.003 or more, and most preferably 0.005 or more. The MShydrophobe is preferably 0.020 or less, more preferably 0.015 or less, and most preferably 0.010 or less. The hydrophobic groups are suitably derived from a glycidyl ether or a chloroglyceryl ether of a C10 to C18, preferably C12 to C16, and most preferably C12 to C14 alcohol that is preferably ethoxylated; from a C10 to C18, preferably C12 to C16, and most preferably C12 to C14 alkyl halide; or from a C12 to C20, preferably C14 to C18, and most preferably C14 to C16 α-olefin epoxide.
The terms DSalkyl, MShydrophobe, and MShydroxyalkyl are used in their regular connotation, and give an overall account of the average number of the different substituents per anhydroglucose unit. DS, the degree of substitution, is the average number of hydroxyl positions on the anhydroglucose unit that have been reacted, and can by definition vary between 0 and a maximum of 3. MS, the molar substitution, is defined as the number of moles of reagent present per mole of anhydroglucose unit. This number could by definition be higher than 3. For example, once a hydroxyl group of the anhydroglucose unit has reacted with one reagent molecule, e.g. with an alkylene oxide molecule, the newly formed hydroxyl group can further react with an additional alkylene oxide molecule. The process could then be repeated several times, forming polyoxyalkylene chains.
In the cellulose ether, at least one of DSalkyl and MShydroxyalkyl is not 0.
Suitable examples are water-soluble alkyl cellulose ethers, such as hydroxyethyl cellulose (HEC), ethyl hydroxyethyl cellulose (EHEC), hydroxybutyl methylcellulose (HBMC), hydroxypropyl methylcellulose (HPMC), methyl ethyl hydroxyethyl cellulose (MEHEC), and hydrophobically modified ethyl hydroxyethyl cellulose (HMEHEC).
Ethyl hydroxyethyl cellulose (EHEC) and methyl ethyl hydroxyethyl cellulose (MEHEC) having a 1% viscosity of at least 7,000, preferably at least 8,000, more preferably of at least 10,000 mPa*s are especially suitable.
When the polysaccharide ether is a guar gum ether, it is preferably a hydroxypropyl guar gum.
The substituents and the degree of substitution are chosen such that the polysaccharide ethers, of the invention are water-soluble.
Herein a product will be defined as water soluble, if after adding 1 g of product per litre water (0.1% by weight) with stirring at 25° C., adjustment of the pH to a value of 6-7, using NaOH or HCl as appropriate, and after further stirring for 16 hours at said temperature, at least 20, preferably at least 40, more preferably at least 60, even more preferably at least 80 and most preferably at least 90% by weight of the product added is dissolved in the water.
The degree of substitution of hydroxyalkyl and alkyl groups, MShydroxyalkyl, MShydrophobe and DSalkyl, can be determined by gas chromatography following degradation of the cellulose ether with HBr in glacial acetic acid, according to the procedure set out in Stead, J. B., & Hindley, H., (1969) “A modified method for the analysis oxyethylene/oxypropylene copolymers by chemical fission and gas chromatography” Journal of Chromatography, 42, 470-475.
The polyol having 3-4 hydroxyl groups suitable for use in the present invention is a non-ionic compound, preferably selected from the group consisting of pentaerythritol, glycerol, trimethylolpropane, di-trimethylolpropane, erythritol, threitol, C2-4 alkylene oxide adducts thereof, and mixtures thereof. The C2-4 alkylene oxide adducts are preferably obtained by reacting the starting polyol with from 1, 2, 3, 4 or 5, to 50, 30, 25, 20 or 10 moles of alkylene oxide per mole of starting polyol. The alkylene oxide is preferably ethylene oxide. Preferably the polyol having 3-4 hydroxyl groups comprises, or is, glycerol or an ethylene oxide adduct of glycerol.
The salt of a multivalent inorganic anion, i.e. a salt with an inorganic anion having two or more negative charges, for use in the present invention is preferably selected from the group consisting of sulfates, phosphates and mixtures thereof. Suitable sulfate salts include sodium sulfate and potassium sulfate. Suitable phosphate salts include orthophosphate and polyphosphate salts, such as diammonium orthophosphate, ammonium diphosphate, disodium orthophosphate, sodium pyrophosphate, dipotassium orthophosphate, potassium pyrophosphate, sodium hydrogen orthophosphate and potassium hydrogen orthophosphate. The salt is needed in the composition to suppress the swelling of the polysaccharide ether.
The multivalent inorganic anion salts are typically provided in the water, as salt water. The concentration of the multivalent inorganic anion salt in the salt water is below the saturation concentration at 20° C. and atmospheric pressure, typically from 4 to 20 wt %, based on the total weight of the salt water.
In the liquid composition of the invention, the weight ratio of the polyol having 3-4 hydroxyl groups to the salt water is preferably from 75:25 to 95:5, more preferably from 80:20 to 90:10. It is important to have an appropriate balance between the polyol and salt water. Too much polyol results in a highly viscous composition which is not easily diluted in water. Too much salt water results in worsened freeze-thaw properties.
On the other hand, a high total amount of polyol is needed to enable a high concentration of polysaccharide ether, and a certain amount of water is needed to reduce the viscosity.
The liquid composition of the present invention can contain further components in addition to those mentioned above, such as pH adjusting agents, polymeric carboxylic acids and preservatives.
The desired pH of the composition of the invention is preferably around neutral, such as from 6 to 8. Suitable pH adjusting agents include acids, and bases. The pH adjusting agent is added in sufficient amounts to yield the desired pH. Citric acid, for instance, could suitably be included in the composition of the invention at a concentration of from 0.001 to 1 wt %, preferably from 0.01 to 0.5 wt %, based on the total weight of the composition.
Polymeric carboxylic acids, or fully or partially neutralized salts thereof can suitably be included in the composition of the invention in order to further improve the dilution properties. Suitable polymeric carboxylic acids are water soluble and include poly(meth)acrylic acid and copolymers of (meth)acrylic acid with one or more ethylenically unsaturated monomers. The polymeric carboxylic acids are preferably provided as the fully or neutralized salts, such as the sodium salt. The polymeric carboxylic acids can suitably be included in the composition of the invention at a concentration of from 1 to 10, preferably 2 to 8, more preferably from 4 to 6 wt %, based on the total weight of the composition. The weight average molecular weight of the polymeric carboxylic acids is preferably in the range from 500 to 50.000 Da, such as from 1000 to 10.000 Da.
Preservatives can suitably be included in the composition of the invention to prevent microbial growth therein.
The composition of the invention is liquid in the sense that it is in liquid state at 20° C. and a pressure of one atmosphere.
The liquid composition of the invention is typically prepared by dispersing the polysaccharide ether in powder form in a mixture comprising the polyol having 3-4 hydroxyl groups, water, salt of multivalent inorganic anion and optionally further components. Suitably, the salt of multivalent inorganic anion is mixed with water, followed by addition of the polyol having 3-4 hydroxyl groups. Subsequently, the polysaccharide ether is mixed with the water/salt/polyol system.
In another aspect, the present invention relates to the use of a mixture comprising a polyol having 3-4 hydroxyl groups, water and at least one salt of a multivalent inorganic anion, and optionally a polymeric carboxylic acid or salt thereof, as a dispersion agent for a non-ionic, water-soluble polysaccharide ether, wherein the weight ratio of the polyol to the sum of water and salt(s) of multivalent anion in the mixture is from 75:25 to 95:5, preferably from 80:20 to 90:10, and the concentration of the salt of multivalent anion in water is from 4 to 20 wt % based on the total weight of the salt and water, as well as the a liquid composition comprising from 2 to 30, preferably 2 to 25, more preferably from 5 to 20, most preferably from 8 to 16 wt %, based on the total weight of the liquid composition, of a water-soluble, non-ionic polysaccharide ether and from 70 to 99, preferably from 75 to 98, more preferably from 80 to 95 and most preferably from 84 to 92 wt %, based on the total weight of the liquid composition, of such a mixture, wherein the water soluble non-ionic polysaccharide, the polyol having 3-4 hydroxyl groups, the salt of a multivalent inorganic anion and the polymeric carboxylic acid or salt thereof are as defined herein.
In another aspect, the present invention relates to a method of preparing an agricultural formulation, comprising adding at least one agriculturally active agent and the liquid composition of the invention to water in amounts to obtain a concentration of the polysaccharide ether of from 0.005, preferably from 0.01, more preferably from 0.02, still more preferably from 0.03 and most preferably from 0.04, to 0.5, preferably to 0.4, more preferably to 0.3, even more preferably to 0.2 and most preferably to 0.1 wt %, based on the total weight of the agricultural formulation. Alternatively, the water could be added to the at least one agriculturally active agent and the liquid composition of the invention. The agricultural formulation will also contain the polyol having 3-4 carboxyl groups and the multivalent ion salts, as they were added with the polysaccharide ether.
In one embodiment, the liquid composition of the present invention, in its concentrated state, with a polysaccharide ether concentration of from 2 to 30 wt %, further comprises at least one agriculturally active agent. In such composition, the ratio of water-soluble polysaccharide ether to agriculturally active agent is selected such that when the composition is added to water to a suitable end-use concentration of the polysaccharide ether, the desired end-use concentration of the agriculturally active agent is reached. Hence, in the method above, and where an agriculturally active agent is present in the concentrated liquid composition, the step of adding at least one agriculturally active agent to water is optional.
In the agricultural formulation, the concentration of the agriculturally active agent is the desired end-use concentration at which it is to be applied to the plants. Those skilled in the art will understand that this desired concentration will depend on the type of agriculturally active agent used, the plant to be treated, efficacy enhancing adjuvants in the formulation, weather conditions, etc. However, the concentration of the agriculturally active agent is typically in the range of from 0.005, 0.01, 0.02, 0.03 or 0.04, to 2, 1, 0.5, 0.4 or 0.1 wt %, based on the total weight of the agricultural formulation.
Agriculturally active agents suitable for use in the present invention include organic compounds that are classified as pesticides or plant growth regulators.
As used herein, the term “pesticide” refers to an organic compound which will prevent, destroy, repel or mitigate any pest. Pesticides contemplated for use in the present invention include fungicides, herbicides, insecticides, miticides, nematicides, acaricides, and molluscicides.
As used herein, the term “plant growth regulator” refers to an organic compound, which through physiological action will accelerate or retard the rate of growth or rate of maturation or otherwise alter the behaviour of ornamental or crop plants or the products thereof. Plant growth regulators contemplated for use in the present invention include abscisic acids, auxins, cytokinins and gibberellins.
Preferred pesticides contemplated for use in the present invention include pesticides and plant growth regulators of the classes triazoles, strobilurins, alkylenebis(dithiocarbamate) compounds, benzimidazoles, phenoxy carboxylic acids, benzoic acids, sulfonylureas, triazines, pyridine carboxylic acids, neonicotinides, amidines, organophosphates, and pyrethroids, and salts and esters of the acid compounds.
Examples of fungicides contemplated for use in the present invention include fungicides of the classes triazoles (e.g. tebuconazole, tetraconazole, cyproconazole, epoxiconazole, difenconazole, propiconazole, prothioconazole), strobilurins (e.g. trifloxystrobin, azoxystrobin, fluoxastrobin, pyraclostrobin), alkylenebis(dithiocarbamate) compounds (e.g. mancozeb) and benzimidazoles (e.g carbendazim).
Examples of herbicides contemplated for use in the present invention include phenoxy carboxylic acids (e.g. 2,4-D-acid, MCPA), benzoic acids (e.g. Dicamba-acid), sulfonylureas (e.g. methylsulfuron-methyl, rimsulfuron), triazines (e.g. atrazine and simazine), triazolinones (e.g. amicarbazone) and pyridine carboxylic acids (e.g. triclopyr).
Examples of insecticides contemplated for use in the present invention include neonicotinides (e.g. thiamethoxam, clothianidin, thiacloprid, dinotefuran, acetamiprid, nitenpyram, imidacloprid), amidines (e.g. amitraz), organophosphates (e.g. chlorpyrifos) and pyrethroids (e.g. permethrin, bifenthrin, deltamethrin).
For a detailed description of each of the above-mentioned pesticides and plant growth regulators, reference is made to handbooks, e.g. “The e-Pesticide Manual v4.0” from BCPC Publications Ltd, Alton, Hampshire. (ISBN 1 901396 42 8).
In addition to the water, the water-soluble, non-ionic polysaccharide ether, the polyol having 3-4 carboxyl groups, the salt of multivalent inorganic anion and the agriculturally active agent, the agricultural formulations of the present invention may contain additional components. Non-limiting examples of such additional components include for example oils, co-solvents, and other adjuvants, such as surfactants, that are conventionally used to increase the bioefficacy of agricultural active ingredients.
The agriculturally active agent may, depending inter alia on its water solubility and the desired concentration, be added to the water as a powder, granulate or liquid, dissolved in a solvent, or dispersed/emulsified in a continuous phase, as is known in the art.
In the agricultural formulation of the present invention, the agriculturally active agent may be present as dispersed particles, in emulsion droplets and/or dissolved in the aqueous phase.
In yet another aspect, the present invention relates to a method for treating a plant, comprising the step of contacting the plant with the agricultural formulation of the invention, preferably by means of spraying the agricultural formulation onto the plant.
Sample formulations as described in Table 1 below were prepared by first mixing ammonium sulphate (AMS), together with sodium tripolyphosphate (STPP) and citric acid (CA) into water, followed by addition of glycerol. Thereafter methyl ethyl hydroxy ethyl cellulose (MEHEC) and polyacrylic acid (PAA) was added. All mixing steps were performed at room temperature under atmospheric pressure using a mechanical overhead mixer.
The MEHEC used in this example was a methyl ethyl hydroxylethyl cellulose having MShydroxyethyl of 1.1, DSethyl of 0.3, DSmethyl of 0.7 and a 1% viscosity of 12,000 mPa*s (ex AkzoNobel), and was provided as a powder.
The polyacrylic acid used in this example had a weight average molecular weight of about 5,000 Da (ex AkzoNobel), as was provided as a powder.
The initial appearance of the samples was assessed by ocular inspection directly after the sample preparation. Thereafter, the samples were subjected to a freeze-thaw treatment by putting the samples in a freezer at −20° C. over night, thawing the samples at +25° C. for about 6 hours, and repeating this freeze-thaw cycle two more times. After this treatment, the samples were gently shaken by hand and their appearance was again assessed.
The results from this experiment are reported in Table 1 below.
From the results in Table 1, it is apparent that the samples according to the invention were pourable liquids and stable towards the freeze-thaw treatment.
The dissolution properties of samples O to T from Example 1 above were tested according to the following.
To a 500 ml beaker, 300 ml of water was added. About 1 g of the sample was added to the water under gentle magnetic stirring at room temperature. The dissolution progress was monitored visually and the time it took for all traces of solid to disappear was recorded, and is reported in table 2 below.
As is apparent from the results, the samples of according to the invention were easier to dilute in water, and that the addition of polyacrylic acid further improved the dissolution properties.
| Number | Date | Country | Kind |
|---|---|---|---|
| 13194847.3 | Nov 2013 | EP | regional |
| Filing Document | Filing Date | Country | Kind |
|---|---|---|---|
| PCT/EP2014/072385 | 10/20/2014 | WO | 00 |
| Number | Date | Country | |
|---|---|---|---|
| 61894103 | Oct 2013 | US |
