Synthetic resins or natural rubbers -- part of the class 520 ser – Synthetic resins – At least one aryl ring which is part of a fused or bridged...
Reexamination Certificate
2001-10-12
2004-01-13
Lipman, Bernard (Department: 1713)
Synthetic resins or natural rubbers -- part of the class 520 ser
Synthetic resins
At least one aryl ring which is part of a fused or bridged...
Reexamination Certificate
active
06677399
ABSTRACT:
This invention relates to agrochemical formulations and in particular to such formulations in solid granular form and especially to such formulations where the granules are dispersible in water.
Agrochemical formulations are commonly applied by spraying, usually in an aqueous medium, in which the active agrochemical may be dissolved, dispersed or emulsified either as such or dissolved in a water immiscible solvent. In meeting the demand for a reduction in the risk to the end user, solid formulations are attractive because the active agrochemical is immobilised, and solid formulations can be of higher density than liquid formulations. It is also desirable that the water dispersible granule form of the agrochemical formulation is non-dusting and typically has a particle size of from 200 &mgr;m to 2 mm. The dusting tendency of the granules can be improved (dusting reduced) by using binder materials in making the solid formulation, but this may detract from the speed and extent to which the granules disintegrate when placed in water especially if the binder is not water soluble. Materials in current use for this function include, polyvinylpyrrolidone (PVP), polyvinyl alcohol (PVOH), carbomethoxycellulose (CMC), starch, alginate, gum arabic, sorbitol, and sucrose.
Dispersing agents are commonly included in agrochemical water dispersible granules to help disperse the active ingredient in water. Examples of conventional dispersing agents include sodium and ammonium salts of naphthalene sulfonate formaldehyde condensates; sodium, calcium and ammonium salts of lignosulfonates; sodium and ammonium salts of maleic anhydride copolymers and sodium salts of condensed phenolsulphonic acid.
The present invention is generally directed to agrochemicals in the form of water dispersible granules including styrene (meth)acrylic copolymers as dispersing agents for the agrochemical on mixing with water and in particular can provide good dispersion and suspension properties after extended storage (ageing) of the dry granules.
The present invention accordingly provides an agrochemical formulations in solid granular form which is dispersible in water and which includes:
1 one or more water dispersible agrochemical active components; and
2 a dispersing agent including a water dispersible styrene (meth)acrylic copolymer.
The present invention includes an agrochemical formulation in solid granular form which is dispersible in water and which includes:
1 one or more water dispersible agrochemical active components;
2 a dispersing agent including a water dispersible styrene (meth)acrytic copolymer; and at least one of:
3 one or more solid support materials;
4 one or more wetting agents;
5 one or more adjuvants; and/or
6 one or more water soluble matrix materials.
In particular, the invention provides an agrochemical formulations in solid granular form which is dispersible in water and which includes:
1 one or more water dispersible agrochemical active components;
2 a dispersing agent including a water dispersible styrene (meth)acrylic copolymer;
3 one or more solid support materials; and
4 one or more wetting agents; and optionally
5 one or more adjuvants; and/or
6 one or more water soluble matrix materials.
The invention includes a method of making a spray mix in which an agrochemical formulation in solid granular form of the invention is dispersed in water. The invention further includes a method of treating plants in which the plants or the soil surrounding the plants are sprayed with a spray mix made by dispersing an agrochemical formulations in solid granular form of the invention in water.
The water dispersible styrene (meth)acrylic copolymer used in this invention is for convenience sometimes referred to below as a polymeric dispersant. The polymeric dispersant is a styrene (meth)acrytic acid copolymer. The repeating units in the copolymer are conveniently considered as residues of monomer components.
The (meth)acrylic acid monomer(s) can be acrylic acid, methacrylic acid, crotonic acid or a mixture of two or more of these. The (meth)acrylic acid monomer(s) can be or include (meth)acrylic monomers which are derivatives of (meth)acrylic acid which include strong acid, especially sulphate acid or sulphonic acid groups (or their salts). Examples of such monomers include acrylamido methyl propyl sulphonate (AMPS) and (meth)acrylic acid isethionate. When present such strong acid modified monomers usually form from 1 to 30 mole %, more usually 2 to 20 mole %, and desirably from 5 to 15 mole %, of the acrylic acid monomers in the copolymer.
The styrene monomer(s) can be, and desirably is, styrene as such or a substituted styrene particularly a hydrocarbyl, desirably alkyl, substituted styrene, in which the substituent(s) are on the vinyl group or on the aromatic ring of the styrene e.g. &agr;-methyl styrene and vinyl toluene. As with the (meth)acrylic acid monomer, the styrene monomer can be or include styrene monomers including strongly acid, particularly sulphonic acid substituents. When present such strong acid modified monomers usually form from 1 to 30 mole %, more usually 2 to 20 mole %, and desirably from 5 to 15 mole %, of the styrene monomers in the copolymer.
In the water dispersible styrene (meth)acrylic copolymer used in the invention, the molar ratio of residues of the (meth)acrylic acid monomer(s) to those of the styrene monomer(s) is generally from 20:1 to 1:5, more usually 10:1 to 1:2 and particularly from 3:1 to 1:1. Generally correspondingly, the proportions of residues of the monomers by weight are typically from 93 to 10%, more usually 87 to 25%, particularly 67 to 40%, of the (meth)acrylic acid monomer(s) and from 7 to 90%, more usually 13 to 75%, particularly 33 to 60%, of the styrene monomer(s).
Other monomers, such as acidic monomers e.g. itaconic acid or maleic acid or anhydride; strongly acidic monomers such as methallyl sulphonic acid (or a salt); or non-acidic acrylic monomers e.g. acrylic esters which may be alkyl esters particularly C
1
to C
6
alkyl esters such as methyl methacrylate, butyl methacrylate or butyl acrylate or hydroxy alkyl esters particularly C
1
to C
6
hydroxyalkyl esters such as hydroxy ethyl methacrylate, or hydroxy propyl methacrylate; or vinyl monomers such as vinyl acetate, can be included. Typically, the proportion of such other monomer(s) will be not more than about 25 mole %, usually not more than about 15 mole %, more usually not more than about 5 mole %, of the total monomers used. The proportion by weight of other monomers will typically be not more than about 30%, usually not more than about 20%, more usually not more than about 10%.
The polymeric dispersant can be a single styrene acrylic acid copolymer or a blend including two or more such copolymers. In particular, when strong acid residues are included in the polymeric dispersant, the dispersant can be a blend of copolymer including strong acid residues and copolymer not including such residues. In such blends, it is generally desirable that the ratio of such copolymers is from 1:10 to 10:1, more usually 5:1 to 1:5, by weight. In particular, the proportion of copolymer including strong acid residues is desirably at least 25%, more usually at least 40%, by weight of the polymeric dispersant.
When strong acid residues are included in the polymeric dispersant, the overall proportion of monomer residues including strong acid groups is desirably from 0.25 to 25 mole %, more usually from 0.5 to 20 mole % and desirably from 1 to 10 mole %.
The inclusion of monomers having strongly acidic substituent groups in the polymeric dispersant can provide improved dispersion of the solid granular form of the agrochemical formulations when dispersed in hard water, particularly water having a hardness above 500 ppm e.g. up to 1000 ppm, up to 2000 ppm or even up to 5000 ppm.
The polymeric dispersant desirably has a molecular weight of from 750 to 20000, more desirably from 1000 to 10000 and particularly from 1500 to 5000. The polymeric dispersant can be used as the free acid or as a salt. In practice, the form
Crossman Martin Charles
Den Tandt Youry
Hartmann Frank Dirk Jozef
Herbert Richard Michael
Reekmans Steven Irene Jozef
Imperial Chemical Industries PLC
Lipman Bernard
Pillsbury & Winthrop LLP
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