FR2777421A1 - Coating of seeds with aqueous, stable seed coating composition - Google Patents

Abstract

Seeds are treated by applying a phytosanitary composition to seeds using a coating of a filmogenic adhesive, using up to 20 liters of coating composition per quintal of seeds, this composition being aqueous and stable. The coating process may be followed by a drying process, the coating formulation has the active material in low concentration, and the minimum amount of formulation used in the process is at least 3 kg/quintal of seed. Independent claims are also included for: (1) a coating formulation; and (2) the preparation of the coating formulation comprising: (a) mixing at least one anionic surfactant with at least one alkoxylated styrylphenol dispersing agent and optionally at least one non-phytotoxic solvent to prepare a mixture (A); (b) mixing at least one coating polymer with optionally a colorant, pigment or soluble colorant absorbed in alumina lacquer to prepare a mixture (B); and (c) adding water to (A), (B), an active ingredient and optionally antifoaming agent.

Description

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  The subject of the present invention is a novel film-forming composition intended for the treatment of seeds, in particular to ensure their protection against pests of plants such as insects, worms or fungi. Indeed, vis-à-vis these attacks, the protection of plants is carried out more and more at the level of the seed itself, rather than by spraying plants. For this purpose, filming techniques consisting of fixing the treatment products on the seeds by means of adhesive film-forming compositions are used. The main advantages of these film-coating techniques are as follows: they do not harm the environment because only the seeds are in contact with the phytosanitary active ingredients; - they are less dangerous for the farmer because the risks of inhalation of toxic products are considerably reduced or even eliminated; - they allow precise dosing of the active ingredients on each seed; and - they provide early protection of seedlings, as early as

first days of germination.

  Many types of seeds are treated by laminating vegetable seeds, floral, grass, but also seeds of great

  such as wheat, maize, sunflower or rapeseed.

  Adhesive film-forming compositions for fixing active ingredients have been described in the literature. They include non-phytotoxic polymers such as cellulose derivatives as per

  hydroxypropyl methylcellulose, methylcellulose, hydroxypropylmethylcellulose,

  ethyl cellulose, carboxymethyl cellulose or hydroxypropyl cellulose,

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  vinyl polymers, for example polyvinyl alcohol or polyvinylpyrrolidone, acrylic polymers such as, for example,

  polymers of acrylic acid, or poly-methyl methacrylates.

  They also include plasticizers such as, for example, polyols such as, for example, glycerol, sorbitol or glycols, hydrophilic fatty acid derivatives such as, for example, ethoxylated fatty acids or acetylated glycerides, inert fillers such as for example talc, silica, silicates, cellulose, mica or carbonates dyes or pigments such as for example iron oxides, titanium dioxide or soluble dyes adsorbed on

alumina lacquers.

  Such compositions are described for example in the application

  French patent published under number 2 548 675.

  In order to carry out a seed treatment by film-coating using the film-forming compositions described above, a film-coating slurry is firstly prepared by dispersing in 100 parts of water, from 50 to 150 parts per hectolitre of phytosanitary product, then we add 50 to

parts of film-forming composition.

  This lamination slurry must be sufficiently fluid and stable to be applied on a bed of seeds. By fluid slurry is meant a pumpable slurry, i.e., which has a viscosity of less than about 10,000 mPas at room temperature, preferably less than 2,000 mPas. Stable slurry means a slurry that does not decant

  and which remains homogeneous during the time of its implementation.

  Seed lamination takes place in different types of machines, all of which allow the seeds to move, whether by rotating a drum, driving by means of a screw, blowing air, or by any other means. mechanical means, and the addition of the coating slurry by means of pumps, troughs, spray

any other suitable means.

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  To avoid any problems of storage or germination of the film-coated seeds, it is essential to control the residual moisture in the seeds after treatment, and to keep it as close as possible to the value before coating. The quantities of water to be used in the treatment, and therefore the quantities of slurries to be applied are therefore necessarily limited. In general, 1 to 20 l of slurry per quintal of treated seed is used. Colza seeds, for example, are often treated with 17 l of slurry per quintal of seeds. Drying may optionally be performed at the machine outlet, to remove the moisture provided by the treatment, for example by blowing hot air or by dusting an adsorbent powder. When the phytosanitary product to be applied can not be used in the presence of water, or when it is used at concentrations such that the slurries are not fluid or are unstable or even unfeasible with the conventional film-forming compositions, the process described

previously is inapplicable.

  This is the case with certain insecticides formulated as oils, oils adsorbed on solid carriers or insoluble powders such as in particular organophosphorus insecticides and especially N-isopropyl-thio-phosphoramidate O-ethyl and of

  O- (isopropoxy-carbonyl-2-phenyl) better known as Isophenphos.

  This oil, which has a solubility of only 20 mg / l in water, acts by inhibition of cholinesterase on a large number of insects and must be used at a dose of 400 g / quintal of rapeseed or sunflower. A method of using this oil without water by mixing with rapeseed seeds and then dusting with an adsorbent powder such as talc has been described in the German patent published under the number

DE 3225008.

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  Currently, lsophenphos is marketed under the trademark OFTANOL in the form of a dry powder adsorbed at 5 or 10% of active ingredient, depending on whether or not it is associated with bis disulfide.

  (dimethyl-thiocarbamoyl), also called TMTD.

  Due to the dilution of the active ingredient in this formulation, up to 4 kg commercial product per seed quintal will be required to provide effective insect protection. However, the addition of such large amounts of active ingredient in the form of a stable and fluid slurry, in a proportion of 10 l of boiled ol per quintal of seed, according to the process previously described, is impossible. Seedlings are therefore forced today to provide such insecticides by dusting on undried seedlings. However, this process leads to poor fixation of the treatment product on the

  seed and with a matte and irregular appearance of the treated seed.

  Some then proposed multilayer or "sandwich" treatments consisting of alternating film-forming layers and layers of powder treatment products. An example is given in the

  Patent Application Publication No. 2,687,038.

  The fixation of the phytosanitary material, as well as the final appearance of the seeds, is in this case significantly improved, but this process is

  more difficult to implement and expensive in time.

  These processes by dusting the active ingredient are all dust generators particularly harmful and irritating to the operators, who are obliged to wear masks and equipment

  special. In addition, the risks of pollution of the environment are high.

  The applicant has therefore sought to develop a "clean" process, without generation of dust, allowing the fixation on the seeds of large quantities of treatment products weakly

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  dosed as active ingredient, in a single step, in the form of a slurry

concentrated fluid and stable.

  The subject of the invention is a process for treating a seed intended to allow the fixing on said seed of at least one phytosanitary active ingredient by laminating an adhesive film-forming composition, by means of a quantity less than or equal to 20 liters per quintal of seed to be treated, a film-coating slurry, aqueous, fluid and stable, characterized in that -this process is a filming in one step, followed, if necessary or if desired, a drying step the slurry comprises the active ingredient in the form of a low dose formulation, and the minimum feed endite formulation in said process is

  greater than or equal to 3 kilograms per quintal of seed to be treated.

  In the above definition, it is understood that the expression film-coating in one step excludes any coating process consisting of alternating film-forming layers with layers of powder products as described for example in the French patent application published under

the number FR 2687038.

  By low dosage formulation is meant a formulation concentrated to less than about 20% by weight of phytosanitary active ingredient. When it is stated in the process as defined above, that the minimum intake endite formulation is greater than or equal to 3 kilograms per quintal of seed to be treated, it means that in the case of a formulation concentrated to 10% by weight active ingredient, the

  this active ingredient will be 300 grams per quintal of seed to be treated.

  By fluid concentrated aqueous slurry, is meant a slurry which can be pumped, that is to say generally having a viscosity at room temperature of less than or equal to 10,000 mPas, preferably

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  less than 2000mPas and more particularly less than 1500mPas; stable slurry means a slurry that does not decant and remains

homogeneous during its implementation.

  As a phytosanitary formulation concentrated to less than about 20% by weight of said active material is meant mainly oils, oils adsorbed on a solid support or dry powders; Such formulations are known to those skilled in the art. The process as defined above is mainly carried out with a film-coating slurry which comprises at least 30% by weight.

  10 weight of active ingredient formulation.

  Active ingredient means, in the process as defined above, any substance, or any mixture of substances, of natural or synthetic origin, of a chemical or biological nature, favoring or protecting the development of the seed or the plant. Such an active ingredient may be, for example, a fungicidal or herbicidal agent, a germination activator, or an insecticidal agent; the active ingredient

  is more particularly a family insecticide of organic compounds

  phosphorus; this is particularly the isophenphos associated or not with

  TMTD marketed in France under the trademark OFTANOL T.

  In addition to the active substance formulation, the slurry used in the process which is the subject of the present invention comprises in particular: at least one anionic surfactant, at least one dispersing agent of the alkoxylated styrylphenol family, and

at least one film-forming polymer.

  By anionic surfactant is denoted by one or more compounds chosen from those of formula (Ia), (Ib) or (Ic): CH 2 (COOR 2) CH (COOR 2) -SO 3 XI (la) R 1 -O-SO 3 X, (Ib) R1-COOX, (Ic)

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  in which R 1 and R 2, which may be identical or different, represent, independently of one another, a hydrogen atom, a solubilising cation or a linear or branched, saturated or unsaturated, cyclic or acyclic hydrocarbon-based radical comprising from 1 to 30 carbon atoms, and X1 represents a hydrogen atom or a solubilizing cation, it being understood that in formula (Ia), when they are identical, R1 and R2 do not represent an atom

  hydrogen, or a solubilizing cation.

  The term "solubilizing cation" denotes, in particular, cations derived from alkali or alkaline earth metals, such as, for example, sodium,

  potassium, magnesium, or calcium.

  The anionic surfactant used in the process which is the subject of the present invention generally consists of one or more compounds of formula (Ia), preferably of one or more alkali or alkaline earth metal dialkyl sulphosuccinate, and more particularly

  sodium dioctyl sulfosuccinate.

  The term "alkoxylated styryl phenol" denotes in particular alkoxylated distyryl phenols or alkoxylated tristyryl phenols alone or in mixtures, as well as sulphated or phosphate derivatives of these compounds. According to another preferred variant of the process which is the subject of the present invention, the alkoxylated styryl phenol used is an ethoxylated tristyryl phenol having an EO value of between 3 and 30, preferably between 5 and 20, or an ethoxylated and sulphated tristyryl phenol. having an EO value between 3 and 30, of

preferably between 5 and 20.

  The film-forming polymers used in the process that is the subject of the present invention are non-phytotoxic; these are mainly cellulosic polymers such as, for example, methylcellulose, ethylcellulose, hydroxypropylcellulose, hydroxypropylmethylcellulose, cellulose acetate phthalate or cellulose acetate; polymers

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  vinyl such as polyvinyl alcohol or polyvinyl pyrrolidone; acrylic polymers, such as, for example, polymers of acrylic acid or polymethacrylates; or polymers of natural origin, such as polysaccharides such as modified starches, gums, alginates or chitosans. According to another preferred variant of the process which is the subject of the present invention, the film-forming polymer is chosen

  by cellulosic, vinyl or acrylic polymers.

  In addition to the compounds defined above, the slurry used in the process which is the subject of the present invention may comprise antifoaming agents, plasticizing agents such as polyethylene glycols, non-phytotoxic solvents such as polyols such as glycerol or sorbitol. or glycols, such as, for example, ethylene glycol, propylene glycol, butylene glycol, pentylene glycol or hexylene glycol; hydrophilic fatty acid derivatives such as, for example, ethoxylated fatty acids or acetylated glycerides, inert fillers such as, for example, talc, silica, silicates, cellulose, mica or carbonates, dyes or pigments such as for example, iron oxides, titanium dioxide or soluble dyes adsorbed on alumina lacquers; In general, the coating slurry used in the process which is the subject of the present invention comprises from 1% to 5% by weight of film-forming polymer, from 0.1% to 5% by weight of an anionic surfactant and from 1% to 5% by weight of film-forming polymer. at 10% by weight of at least one dispersing agent of the alkoxylated styryl-phenol family and, if desired, from 1% to 15% by weight of a non-phytotoxic solvent selected from glycols. According to a particular embodiment of the process as defined above, the film-coating slurry comprises more than% by weight of a dry powder dosed at 5% or 10% by weight of isophenphos, with or without TMTD, of 1% to 5% by weight. % by weight of film-forming polymer, from 0.1% to 5% by weight of an anionic surfactant and from 1 to 10% by weight of at least one dispersing agent of the family of

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  alkoxylated styryl phenols and, if desired, from 1% to 15% by weight of a non-solvent

  phytotoxic selected from glycols.

  The method, as described above, can be used to treat seeds of any type of plant; these include vegetable seeds, floral seeds, grass seeds, cereal seeds such as wheat, corn, barley or oats, oilseed seeds, especially sunflower seeds, seeds of crucifers and especially seeds

  oilseed crucifers and especially rapeseed.

  According to a preferred variant of the process as defined above, applied to isophenphos treatment with or without the TMTD of rapeseeds, the coating slurry comprises dioctyl sodium sulfosuccinate, ethoxylated and sulfated tristyryl phenol having a d EO between 3 and 20 and a film-forming polymer chosen by the cellulosic polymers, vinyl or acrylic and the formulation of isophenphos with or without TMTD, made to the preparation of the slurry, is a dry powder dosed at 5% or 10% by weight of active ingredient. The subject of the invention is also a film-coating slurry as defined above and more particularly a film-coating slurry comprising 30% by weight of a dry powder dosed at 5% or 10% by weight of isophenphos, whether or not associated with TMTD from 1% to 5% by weight of film-forming polymer, selected from cellulose, vinyl or acrylic polymers, from 0.5% to 4% by weight of sodium dioctyl sulfosuccinate and from 1 to 5% by weight of ethoxylated tristyryl phenol and sulfated having an EO value between 5 and 20 and from 1% to 5% by weight of a non-phytotoxic solvent

selected from the gycols.

  The invention further relates to a process for preparing a film-coating slurry as defined above, characterized in that:

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  a mixture (A) comprising at least one agent

  anionic surfactant, at least one dispersing agent of the styryl family

  alkoxylated phenols and, if desired, at least one non-phytotoxic solvent, a film-forming solution (B) comprising at least one film-forming polymer and, if desired, at least one dye or a pigment or a soluble dye adsorbed onto lacquers is prepared. alumina, said mixture (A), the formulation of active material, said mixture (B) and if desired or if necessary, are added to the water under stirring;

an anti-foam agent.

  The invention finally relates to the mixture (A) as defined above, comprising from 30% to 80%, more particularly from 40% to%, by weight of at least one ethoxylated tristyryl phenol having an EO value between 3 and 30, preferably between 5 and 20, or an ethoxylated and sulphated tristyryl phenol having an EO value of between 3 and 30, preferably between 5 and 20, of 1.5% to 30%, more particularly of 3% to 15%, by weight of one or more compounds of formula (Ia), preferably one or more alkali or alkaline earth metal dialkyl sulfosuccinate and, more particularly, sodium dioctyl sulfosuccinate and from 20 to 70% of one or

several glycols.

  The following examples illustrate the invention without limiting it:

EXAMPLE 1

  Demonstrating evidence of the interest of the presence of dispersants of the family of styryl phenols alkokylés in the film coating slurry. A slurry was prepared by mixing with agitation approximately:% water, x% dispersing agent (x = 0% or 5%),% OFTANOL T 3% film-forming agent (vinyl polymer)

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  3% pigment paste 2% antifoaming agent The viscosity was measured and the appearance and the stability at 7 days of the mixture were observed according to the dispersant used dispersant aspect of the viscosity% slurry decantation (mPas) after 7 days no 0 2500 naphthalene 0> 10000 na Na sulphonate

condensed formalin.

  polymer 0> 5000 nd acrylic acid polycarboxylic alcohol 0> 10000 nd isodecyl ethoxylated 40E tristyryl phenol 2 1200 5 ethoxylated (80E) sulphate tristyryl phenol 2 1100 2 ethoxylated (150E) sulphate tristyryl phenol 2,350 7 ethoxylated (220E) sulfate aspect of slurry 0: poor dispersion 1: medium quality dispersion 2: good dispersion

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EXAMPLE 2

  Highlighting the importance of the presence of anionic surfactants in the coating slurry. A slurry was prepared by mixing with agitation approximately:% water, 2% sulphated ethoxylated tristyryl phenol,% OFTANOL T 3% film-forming agent (vinyl polymer) 2% defoamer y% d Anionic surfactant has been found that the presence of an anionic surfactant and more particularly dioctylsulfosuccinate at the side of the dispersing agent, unexpectedly improves the fluidity and stability of the slurry, compared to a slurry of the example 2 without anionic (y = 0%)

EXAMPLE 3

  Process for treating rapeseed seeds with 3.6kq of OFTANOLOT per quintal A coating slurry is prepared by adding to the water under stirring a mixture (A) as defined above, comprising sulphated ethoxylated tristyryl phenol, sodium dioctylsulfosuccinate and a glycol, and a mixture (B) comprising a film-forming polymer and a pigment paste. The slurry has a viscosity of less than 1500mPas and a density of 1.12; it is perfectly fluid and homogeneous and it is stable for more

7 days.

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  This slurry is sprayed for one minute at a rate of about 1 liter per minute on about 1 quintal of rapeseed. After drying, it is found that the seeds are perfectly covered with a homogeneous film. They do not stick together and flow without problems in the hoppers when bagging.

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Claims (18)

  1. A method of treating a seed intended to allow the fixing on said seed of at least one phytosanitary active ingredient, by laminating an adhesive film-forming composition, by means of an amount equal to or less than 20 liters per quintal of seed to be treated, a film-coating slurry, aqueous, fluid and stable characterized in that said process is a filming in one step, followed, if necessary or desired, a drying step, - said slurry comprises the material active in the form of a low dose formulation, and - the minimum endite formulation in said process is   greater than or equal to 3 kilograms per quintal of seed to be treated.   2. The process as defined in claim 1, wherein the formulation of active ingredient is a dry powder, an oil or an oil adsorbed on a solid support.   3. Method as defined in one of claims 1 or 2, in   which the coating slurry comprises at least 30% by weight of formulation of active ingredient.   4. Method as defined in any one of claims 1   at 3, in which the active ingredient is more particularly an insecticide of the family of organophosphorus compounds and particularly of   Isophenphos with or without TMTD.   5. Method as defined in any one of claims 1   at 4, characterized in that said slurry further comprises: - at least one anionic surfactant, - at least one dispersing agent of the alkoxylated styryl-phenol family, and at least one film-forming polymer. 2777421   6. Process as defined in claim 5, wherein the anionic surfactant included in the slurry used consists of one or more compounds chosen from those of formula (Ia), (Ib) or (Ic): CH 2 ( COOR1) -CH (COOR2) -SO3X1 (la) R1-O-SO3X1 (Ib) R1-COOX, (Ic) in which R1 and R2, which may be identical or different, represent, independently of one another, an atom of hydrogen, a linear or branched, saturated or unsaturated, cyclic or acyclic hydrocarbon-based solubilizing or hydrocarbon radical having from 1 to 30 carbon atoms, and X1 represents a hydrogen atom or a solubilizing cation, it being understood that in the formula (la), when they are identical, R1 and R2 do not represent an atom   hydrogen, or a solubilizing cation.   7. A process as defined in claim 6, wherein the anionic surfactant included in the slurry used consists of one or more compounds of formula (Ia), preferably one or more alkali metal dialkyl sulfosuccinate. or alkaline earth and, more   particularly sodium dioctyl sulfosuccinate.   8. Process as defined in any one of claims 5   to 7, wherein the compound of the alkoxylated styryl phenol family is an ethoxylated tristyryl phenol having an EO value of between 3 and 30, preferably between 5 and 20, or an ethoxylated and sulfated tristyryl phenol having a   an EO value between 3 and 30, preferably between 5 and 20.   9. A method as defined in any one of claims 5   at 8, wherein the film-forming polymer is selected by the polymers   cellulosic, vinyl or acrylic.   10. A method, as described, defined at any one of   Claims 1 to 9, in which the slurry used comprises in 162777421   in addition to one or more compounds selected from antifoam agents; plasticizers and more particularly polyethylene glycols; non-phytotoxic organic solvents and more particularly glycerol, sorbitol or glycols; ethoxylated fatty acids; acetylated monoglycerides; inert fillers, more particularly talc, silica, silicates, cellulose, mica or carbonates; dyes or pigments and more particularly iron oxides, titanium dioxide or   Soluble dyes adsorbed on alumina lacquers.   11. A method as defined in any one of claims 1   0 to 10, wherein the coating slurry comprises from 1% to 5% by weight of film-forming polymer, from 0.1% to 5% by weight of anionic surfactant and from 1 to 10% by weight of minus a dispersing agent of the alkoxylated styryl-phenol family and, if desired, from 1% to 15% by weight of a   non-phytotoxic solvent selected from gycols.   A process as described as defined in claim 11, wherein the coating slurry comprises more than 30% by weight of a dry powder dosed at 5% or 10% by weight of isophenphos with or without TMTD, from 1% to 5% by weight of film-forming polymer, from 0.1% to 5% by weight of an anionic surfactant and from 1 to 10% by weight of at least one dispersing agent of the styryl-phenol family alkoxylated and, if desired,   from 1% to 15% by weight of a non-phytotoxic solvent selected from gycols.   13.-Process, as described as defined at any one of   Claims 1 to 12, used to treat vegetable seeds,   floral seeds, sod seeds, cereal seeds, especially wheat, barley or oat seeds, oilseed seeds, especially sunflower seeds, crucifer seed and more particularly seed of   oleaginous crucifers and especially rapeseed.   14. Process, as defined in claim 13, of treatment of a rapeseed seed with isophenphos or not associated with TMTD, 1777721   characterized in that the coating slurry comprises sodium dioctyl sulfosuccinate, ethoxylated and sulfated tristyryl phenol having an EO value of from 3 to 20 and a film-forming polymer selected from cellulosic, vinyl or acrylic polymers. and in that the formulation of isophenphos, whether or not associated with TMTD, made to the preparation of the slurry, is a dry powder dosed at 5% or 10% by weight. weight of active ingredient.   15. Film-coating porridge as defined in any one of the Claims I to 13.   16. The coating slurry as defined in claim 15, comprising more than 30% by weight of a dry powder dosed at 5% or 10% by weight of isophenphos with or without TMTD from 1% to 5% by weight. weight of film-forming polymer, chosen from cellulose, vinyl or acrylic polymers, from 0.5% to 4% by weight of sodium dioctyl sulphosuccinate and from 1 to 5% by weight of ethoxylated and sulphated tristyryl phenol having an EO value between 5 and 20 and from 1% to 5% by weight of a non-phytotoxic solvent selected from the gycols.   17. Process for the preparation of a film-coating slurry such as   defined in one of claims 15 or 16 characterized in that   a mixture (A) comprising at least one agent is prepared   anionic surfactant, at least one dispersing agent of the styryl family   alkoxylated phenols and, if desired, at least one non-phytotoxic solvent, - a film-forming solution (B) comprising at least one film-forming polymer and, if desired, at least one dye or a pigment or a soluble dye adsorbed on lacquer d alumina, said mixture (A), the active ingredient formulation, said mixture (B) and if desired or if necessary, added to the water under stirring; an anti-foam agent. 18 2777421   18. Mixture (A) as defined in claim 17, comprising from 30% to 80%, more particularly from 40% to 60%, by weight of at least one ethoxylated tristyryl phenol having an EO value of between 3 and Preferably between 5 and 20 or an ethoxylated and sulphated tristyryl phenol having an EO value between 3 and 30, preferably between 5 and 20, of 1.5% to%, more preferably of 3% to 15% by weight. weight, one or more compounds of formula (Ia), preferably one or more alkali or alkaline earth metal dialkyl sulfosuccinate and more particularly dioctyl sodium sulfosuccinate and 20 to 70% by weight of a or lo several glycols.