WO2001022795A1

WO2001022795A1 - Flocculating (co)polymer additives and methods for reducing tare in harvested tuber plants

Info

Publication number: WO2001022795A1
Application number: PCT/FR2000/002693
Authority: WO
Inventors: Cyril Collin
Original assignee: Snf S.A.
Priority date: 1999-09-29
Filing date: 2000-09-28
Publication date: 2001-04-05
Also published as: AU7668700A; FR2798818A1; FR2798818B1

Abstract

The invention concerns the use of flocculating polymers, in particular of the partly salified acrylamide/acrylic acid type, about 10 to 50 % anionic or cationic, for reducing tare, or soil sticking to tuber plants, during the harvesting of tuber plants such as sugar beets, carrots, potatoes and the like. The flocculating polymers are directly spread on the soil, in particular in emulsion or powder or solution form, at a dose of about 1 to 3, at times 10 or 20 kg of active matter per hectare, as applicable, thereby enabling to dig the tuber plant more easily, and reducing tare, for example in potatoes, from 24 % to 8 % of the tuber weight.

Description

Flocculating (co) polymer type additives and methods for reducing the tare weight of tubers during harvest.

The present invention relates to the technical sector of flocculating polymers and that of agriculture, in particular the cultivation of so-called "tuber" plants, that is to say underground growth such as sugar and fodder beets, carrots, apples earth, turnips, and generally well-known "onion" plants and the like.

Throughout the present application, the term “polymers” will mean homopolymers as well as copolymers or terpolymers, or optionally more complex copolymers, consisting of one or two, or more, monomers copolymerizable with one another.

A person skilled in the art knows that, when such vegetables are harvested, they are pulled from the ground, in mechanized crops, by machines called "harvesters".

We also know that a large mass of soil adheres to tuber plants during uprooting, a mass known as the "tare", which depends among other things on the type of soil, its water content, and its compaction.

This defect, which does not peel off or come off easily, has serious drawbacks of several kinds. On the one hand, it represents a large mass (which can reach on the order of 30% to 50% of the weight of the harvested tuber plants) whose transport is unnecessary and costly. On the other hand, the tare is rich in nutrients that it is advantageous to leave in the field to save fertilizer inputs. In addition, tare fragments detach during transport and handling and contaminate the roadways, making them slippery and dangerous. The phenomenon is well known in the departments of northern France, a beet growing area. Finally, the tare must be removed by washing, which represents a non-productive operation and, on the contrary, expensive, requiring heavy and costly investments, and which moreover generates drawbacks such as sludge, etc. which must be turn reject or treat.

To date, no process or chemical additive is known which makes it possible to solve this problem. The stake is however considerable, account of the economic parameters indicated above.

France is, for example, the world's leading producer of beet sugar. The average tare of beets in France for the 1998 harvest amounted to 27%, for a production of more than 20 million tonnes, i.e. a total tare of more than 5 million tonnes (source ITB, Technical Institute of Beet ).

It is also known to use certain flocculating polymers in the field of agriculture, in particular to improve irrigation and avoid damage due to excessive or violent runoff.

These flocculating polymers are used in general, in the field of irrigation, by spraying or sprinkling the soil with the irrigation water. They act by soil stabilization, probably by a phenomenon of fixation of fine soil particles. Treatments for irrigation start at the very beginning of sowing, and continue with one treatment every two irrigations, and are stopped a month or two weeks before harvest, depending on the species cultivated.

Thus, for sugar beet, of which about 10% of the crop is irrigated in France, irrigation is stopped about a month before harvest, in order to cause a phenomenon of "stress" in the vegetable, which induces the production of sugar . For carrots or other crops, irrigation is stopped about 15 days before harvest to dry the field and thus facilitate the passage of the harvester. Surprisingly, according to the invention, a process has been discovered according to which the spreading on crops before harvest of at least one, or of (co) flocculating polymers, a few days before harvest, from 3 to 6 or 8 days or up to 30 or 40 or 90 days depending on the species cultivated, reduces the tare in a considerable proportion, while facilitating the uprooting of the vegetable.

According to a first embodiment, the spreading will be carried out, on crops traditionally irrigated, preferably between 3 and 8 or 10 days before harvesting, that is to say during a period when irrigation is traditionally stopped.

According to a less preferred variant, the spreading, on crops traditionally irrigated, will be carried out between 10 or 15 or 30 days before harvest, and up to 40 or 60 (or even 90 days when the product is applied dry) before harvesting, that is to say during a period when irrigation is traditionally carried out.

In the context of this variant, spreading can either be carried out with irrigation or outside the irrigation period.

According to another variant, it may be carried out just before the end of the traditional irrigation period, in order to then be able to clean and store the irrigation equipment.

These choices will be made by the grower according to his habits, his equipment, rainfall and climatic conditions in general, etc.

According to a second embodiment, the spreading will be carried out, on crops traditionally not irrigated, preferably between 3 and 8 or 10 days before harvesting.

According to a less preferred variant, the spreading, on crops traditionally not irrigated, will be carried out between the sowing period and up to 10 or 5 days before harvest, so that the product can penetrate the soil before lifting.

For any product used in powder form, it will be applied at least 15 days, preferably 20 to 30 days, before harvesting.

For any product used in the form of an emulsion or solution, and more generally in any liquid form, spreading will be carried out at least 8 days and up to 30 or 60 days before harvest.

The flocculating polymers which can be used according to the invention are anionic or cationic polymers of molecular weight of the order of 250,000 to 500,000 Daltons and up to 5 to 10, 20 or 30 million Daltons or more.

The monomers used for the preparation of the (co) polymer (s) can be nonionic, but generally at least part of the monomers used to form the polymer is ionic. The monomers are usually monoethylenically unsaturated monomers, sometimes allylic monomers, but generally vinyl monomers. They are generally acrylic or methacrylic monomers. Suitable nonionic monomers are acrylamide, methacrylamide, N-vinylmethylacetamide or formamide, vinyl acetate, vinyipyrrolidone, methyl methacrylate or other acrylic esters, or other ethylenically unsaturated esters, or other vinyl monomers insoluble in water such as styrene or acrylonitrile.

Suitable anionic monomers are, for example, sodium acrylate, sodium methacrylate, sodium itaconate, and their other salts, in particular ammonium and potassium salts, 2-acrylamido-2-methylpropane sulfonate (AMPS), sulfopropylacrylates or sulfopropylmethacrylates, or other water-soluble forms of these polymerizable sulfonic or carboxylic acids. A sodium vinyl sulfonate, or an allylsulfonate, or a sulfomethylated acrylamide may be used. Suitable cationic monomers are dialkylaminoalkyl acrylates and methacrylates, in particular dialkylaminoethyl acrylate, as well as their acid salts or their quaternary products, and also dialkylaminoalkylalkylacrylamides or - methacrylamides, as well as their acid salts and quaternization products , for example methacrylamido-propyl trimethyl ammonium chloride (MAPTAC) and Mannich products such as quaternized dialkylaminomethylacrylamides, as well as diallyldialkylammonium chlorides. The alkyl groups in question are generally CC ₄ alkyl groups.

The monomers may contain hydrophobic groups, as for example described in patent EP 0 172 723, and it will be possible in certain cases to prefer monomers of allyl ether.

The alkyl groups in question are generally C ₁ -C ₄ alkyl groups.

The monomers which can be used for the synthesis of the polymers useful according to the invention are preferably chosen from the following:

non-ionic monomers: acrylamide, methacrylamide

anionic monomers: acrylic acid, methacrylic acid,

cationic monomers: MADAME chloromethylated or sulfomethylated

ADAME chloromethylated or sulfomethylated

DADMAC

A preferred combination of monomers will be that of acrylamide and acrylic acid or a sodium or potassium acrylate. The polymers may be branched or linear or substantially linear.

It is optionally possible to use mixtures of such (co) polymers, that is to say mixtures of anionic, cationic and / or nonionic (co) polymers and / or mixtures of linear and / or branched (co) polymers.

The polymers that can be used according to the invention can be non-limiting anionic polymers, in particular of the order of 10 to 40 or 50% anionics, preferably from 15 to 40% anionics, more preferably from 15 to 30% anionics , the preferred anionic character being around 30% anionic.

Preferably, cationic polymers, in particular at 10 - 50% cationic polymers, the effectiveness of such cationic polymers being approximately 20% higher, will be used, subject to the legislation in force, in laboratory tests.

The polymers which can be used according to the invention are well known in themselves, as are their methods of synthesis.

In particular, they can be prepared by reverse emulsion polymerization. This technique was originally described in USP Patent No.

3,284,393, of November 8, 1966, Vanderhoff et al., And in USP No. Re 28,474 reissued on July 8, 1974, DR Anderson AJ Frisque. This technique requires conventional equipment and low costs for the production and processing of the polymer. It also almost completely reduces the formation of insoluble parts in the polymer. The water-in-oil type emulsion may contain a reasonably high concentration of polymer while remaining fluid, and the high specific surface of the dispersed phase of the polymer makes the polymer very quickly dissolve or swell. Consequently, the use of a water-in-oil type emulsion means that the end user must not only buy the polymer but also oily type surfactants and in some cases a rather large amount of water must be transported, while all of these products will be introduced into the charge used. This also results in a significant additional cost of the raw material, transport and storage, and there are difficulties, moreover, in satisfying national or international regulations or regulations.

According to a variant of the invention, a conventional (co) polymerization in reverse emulsion (water-in-oil) is carried out in a first step leading to the very high molecular weight desired, then the emulsion is dried in a second step to obtain the (co) polymer in powder form, then the powder (co) polymer thus obtained is dispersed or dissolved in an aqueous medium.

According to a first preferred embodiment of the invention, the emulsion is dried in the second step by azeotropic evaporation followed by sedimentation and filtration.

According to a second preferred embodiment of the invention, the drying of the emulsion in the second step is carried out by a spray-drying technique or "spray-drying".

One such spray drying technique has previously been developed by The Dow Chemical Company for drying polyacrylamide emulsions.

This process, which has been used in Central America, involves loading the emulsion into a spray dryer; at the outlet of the dryer, the fines are sent under nitrogen to a cyclone; at the high outlet of the cyclone, the flow is directed to a scrubber which allows the fines contained in an oil phase to be separated into the bottom product. The top product is directed to a condenser then a decanter, which allows the oil phase to be recycled and the water to be separated. The product at the low outlet of the cyclone is combined with the product leaving the dryer. The whole is directed to a mixer then to a compactor, a crusher, a sifter or selector and the desired product is obtained at the grain size desired. The compaction can be helped by a binder, preferably water so as not to introduce an oil phase. According to one embodiment, it is possible to combine compaction cylinders with a pre-granulator then a granulator then a sieve, all possibly in vertical arrangement.

According to a preferred variant, the spray dryer is a device with high energy spraying, and particles of dimensions <20 or <10 microns are obtained; the compactor is replaced by resuspension in water, to a particle size <10 microns, then we pass to the colloidal mill which allows to reach a dimension of the order of a micron.

This variant will be the technology preferably used according to the invention.

By drying, a powder is thus obtained which can be used either directly or after it has been dissolved in an aqueous medium compatible with agriculture, or water.

It is also possible according to the invention to prepare a water-in-oil reverse emulsion, which is then reversed with water, thereby obtaining a product which can be used directly.

According to a third preferred embodiment of the invention, the oil used for the oil-in-water (co) polymerization in emulsion of the first stage has a flash point less than about 65 ° vs.

According to a fourth embodiment, a gel polymerization will be carried out directly with subsequent grinding of the gel to obtain a powder directly, or else a solution polymerization will be carried out, giving either a directly usable solution or a usable powder, after drying of the solution. . According to an entirely preferred embodiment of the general method according to the invention, in the first step, the copolymerization of a mixture of monomers soluble in water or dispersed if they are insoluble in water is carried out. at least one has a hydrophobic character. Preferably, the initial mixture of monomers will comprise a hydrophobic fraction representing between approximately 1 and 40 mol%, preferably 15 and 25 mol% of the mixture of monomers.

According to the invention, the application dose of the polymers will be approximately 1 to 20 kg of active polymer per hectare, preferably from 1 to 10 kg of active material / ha, and more preferably around 1 to 2 or 3 kg of active ingredient / ha, depending on the form of application used.

If the dry powder, as produced directly in synthesis or as described above, is applied to the soil, a dose of approximately 5 to 10 or 20 kg of active ingredient / ha will be used.

If a solution of the dry powder as produced in synthesis is applied, or a solution obtained from the emulsion, a dose of approximately 1 to 5 kg of active material / ha will be used.

If the emulsion, as produced in synthesis, is applied, a dose of approximately 1 to 5 kg of active material / ha will be used.

The application rate naturally depends on the crop, the nature of the crop soil, and other conventional parameters of agriculture.

As will be seen below, a dose of 1.25 kg / ha of acrylamide polymer / acrylic acid-sodium acrylate 30% anionic, of very high molecular weight, made it possible to reduce the tare, on a species of apple soil, from 24% of the tuber's weight to just 8%, a reduction of almost 66%.

With a 40% cationic polymer, a tare reduction was obtained, under the same conditions, of 74%. There was also noted a much greater stripping facility, resulting in a significantly lower stripping force. The machines will therefore be mechanically less stressed. The advantage will also be clearly perceived in the fields where manual uprooting is still practiced.

Those skilled in the art will be able to select the most appropriate dose according to their knowledge, from reading this description and the examples it contains, with the help of a few simple routine tests if necessary.

In addition to the process promoting the harvesting of tubers, which has just been described, the invention also relates to the additives comprising at least one of the polymers described, as well as the compositions promoting the harvesting of tubers, characterized in that that they contain an effective dose, as described, of at least one of the anionic flocculating polymers of very high molecular weight which have also been described.

The agricultural compositions according to the invention will preferably be emulsions, but also solutions or powders, depending on the equipment of the operator.

The emulsions will preferably be emulsions in an aqueous vehicle of the reverse emulsion obtained by the synthesis of the polymer, itself reversed by mixing with said aqueous vehicle.

The aqueous vehicle will preferably be water, optionally comprising other additives useful in agriculture.

As indicated above, it is also possible to use the flocculating polymers in the form of the powders obtained by the synthesis, or of the powders obtained by drying the reverse synthetic emulsion; It is also possible to use a solution of the above powders in an aqueous vehicle, such as water optionally containing additives customary in agriculture.

Additives customary in agriculture can also be added, in a compatible form, to an emulsion according to the invention.

The invention relates to both the above concentrated and diluted compositions.

In the concentrated state, the compositions will be at the following concentrations:

emulsions: 25 to 40% by weight

powders: N / A

solutions: from 2 to 5, 10 or 20% by weight.

In a diluted state, that is to say ready to use by spreading or spraying, the compositions will, by way of nonlimiting examples:

at the following concentrations: and used at the following doses

emulsions: 29% by weight of MA 3 to 15 kg / 1000 liters of water / ha

powders: N / A 1 to 5 kg / 1000 liters of water / ha

solutions: 5% by weight of MA 20 -100 kg / 1000 liters of water / ha

(MA = active ingredients) (N / A = not applicable) The invention also covers the composition and process variants which will be directly accessible to those skilled in the art on reading the above and in the light of their own knowledge.

Claims

1 Process for reducing the tare weight and facilitating the uprooting of so-called "tuber" plants, that is to say underground growth such as beets, sugar or fodder beets, carrots, potatoes, turnips, in general all plants of the “onion” type, and similar tubers, characterized in that at least one or flocculating (co) polymer (s) is spread on the crops before harvest, a few days before harvest, 3 to 6 or 8 days or up to 30 or 40 or 90 days depending on the species cultivated.

2 Method according to claim 1, characterized in that one will apply the spreading, on crops traditionally irrigated, preferably between 3 and 8 or 10 days before harvest, that is to say during a period when irrigation is traditionally stopped.

3 Method according to claim 1 or 2, characterized in that one will apply the spreading, on crops traditionally irrigated, between 10 or 15 or 30 days before harvest, and up to 40 or 60 (or even 90 days when the product is applied dry) before harvest, i.e. during a period when irrigation is traditionally carried out.

4 Method according to claim 1 2 or 3, characterized in that the spreading may either be carried out with irrigation, or outside the irrigation period.

5 Method according to any one of claims 1 to 4, characterized in that the spreading is carried out just before the end of the traditional irrigation period, in order to then be able to clean and store the irrigation equipment. 6 Method according to claim 1, characterized in that one operates the spreading, on crops traditionally non-irrigated, preferably between 3 and 8 or 10 days before harvest.

7 Method according to claim 6, characterized in that one operates the spreading, on crops traditionally non-irrigated, between the sowing period and up to 10 or 5 days before harvest, so that the product can penetrate the soil before lifting.

8 A method according to any one of claims 1 to 7, characterized in that for any product used in powder form, the spreading will be carried out at least 15 days, preferably 20 to 30 days, before harvesting.

9 Method according to any one of claims 1 to 7, characterized in that for any product used in the form of an emulsion or solution, and more generally in any liquid form, the spreading will be carried out at least 8 days and until 30 or 60 days before harvest.

10 Method according to any one of claims 1 to 9, characterized in that the flocculating (co) polymers are anionic or cationic polymers of molecular weight of the order of 250,000 to 500,000 Daltons and up to 5 to 10 , 20 or 30 million Daltons or more.

11 Method according to any one of claims 1 to 10, characterized in that the monomers used for the preparation of the (co) polymer (s) can be nonionic, but generally at least a part of the monomers used to form the polymer is ionic, and the monomers are usually monoethylenically unsaturated monomers, sometimes allylic monomers, but generally vinyl monomers, in particular acrylic or methacrylic monomers.

1 2 A method according to claim 11, characterized in that suitable nonionic monomers are acrylamide, methacrylamide, N-vinylmethylacetamide or formamide, vinyl acetate, vinyipyrrolidone, methyl methacrylate or other acrylic esters, or other ethylenically unsaturated esters, or other water-insoluble vinyl monomers such as styrene or acrylonitrile.

1 3 Process according to claim 11 or 12, characterized in that suitable anionic monomers are for example sodium acrylate, sodium methacrylate, sodium itaconate, and their other salts, in particular ammonium and potassium, 2-acryiamido 2-methylpropane sulfonate (AMPS), sulfopropylacrylates or sulfopropylmethacrylates, or other water-soluble forms of these polymerizable sulfonic or carboxylic acids, in particular sodium vinyl sulfonate, or an allylsulfonate, or a sulfomethylated acrylamide .

1 4 A method according to claim 11, 12 or 13, characterized in that suitable cationic monomers are dialkylaminoalkyl acrylates and methacrylates, in particular dialkylaminoethyl acrylate, as well as their acid salts or their quaternary products, and again dialkylaminoalkylalkylacrylamides or -methacrylamides, as well as their acid salts and the quaternization products, for example methacrylamidopropyl trimethyl ammonium chloride (MAPTAC) and Mannich products such as quaternized dialkylaminomethylacrylamides, as well as diallyldialkylammonium chlorides.

1 5 A method according to any one of claims 11 to 14, characterized in that the alkyl groups in question are generally C ^ C ^ alkyl groups

1 6 A method according to any one of claims 11 to 15, characterized in that the monomers may contain hydrophobic groups, and it may be preferred in some cases allyl ether monomers.

1 7 A method according to any one of claims 11 to 15, characterized in that the monomers which can be used for the synthesis of useful (co) polymers are preferably chosen from the following:

non-ionic monomers: acrylamide, methacrylamide

anionic monomers: acrylic acid, methacrylic acid,

cationic monomers: MADAME chloromethylated or sulfomethylated

ADAME chloromethylated or sulfomethylated

DADMAC

1 8 A method according to any one of claims 11 to 17, characterized in that a preferred combination of monomers will be that of acrylamide and acrylic acid or a sodium or potassium acrylate.

1 9 A method according to any one of claims 11 to 18, characterized in that the (co) polymers may be branched or linear or substantially linear.

20 Method according to any one of claims 11 to 19, characterized in that it is optionally possible to use mixtures of such (co) polymers, that is to say mixtures of anionic, cationic and / or non (co) polymers ionic and / or mixtures of linear and / or branched (co) polymers.

21 Method according to any one of claims 11 to 20, characterized in that the (co) polymers which can be used according to the invention can be anionic polymers, in particular of the order of 10 to 40 or 50% anionics, preferably of 15 to 40% anionic, more preferably 15 to 30% anionic, the preferred anionic character being around 30% anionic. 22 Method according to any one of claims 11 to 20, characterized in that the (co) polymers which can be used according to the invention can be cationic polymers, in particular at 10 - 50% cationic.

23 Method according to any one of claims 11 to 22, characterized in that the (co) polymers which can be used according to the invention are prepared by reverse emulsion polymerization.

24 The method of claim 23, characterized in that one carries out in a first step a conventional (co) polymerization in reverse emulsion (water-in-oil) leading to the desired very high molecular weight, then the emulsion is dried in a second step to obtain the (co) polymer in powder form, then the powder (co) polymer thus obtained is dispersed or dissolved in an aqueous medium, and in that preferably the drying of the emulsion in the second step is carried out by azeotropic evaporation followed by sedimentation and filtration, or by a spray-drying technique.

25 Method according to any one of claims 23 or 24, characterized in that the (co) polymers which can be used according to the invention can be prepared by a reverse water-in-oil emulsion, which is then reversed with water, thus obtaining a directly usable product, where the oil used for the oil-in-water (co) polymerization in emulsion of the first stage has a flash point less than about 65 ° C., either directly by gel polymerization with subsequent grinding of the gel to obtain a powder directly, or else by solution polymerization, giving either a directly usable solution or a usable powder, after the solution has dried.

26 Method according to any one of claims 1 to 25, characterized in that the application dose of the (co) polymers will be approximately 1 to 20 kg of active polymer per hectare, preferably from 1 to 10 kg of active ingredient / ha, and more preferably around 1 to 2 or 3 kg of active ingredient / ha, depending on the form of application used, and, if the dry powder is applied, on the ground, use a dose of approximately 5 to 10 or 20 kg of active ingredient / ha and, if a solution of the dry powder as produced in synthesis is applied, or a solution obtained from the emulsion, a dose of approximately

1 to 5 kg of active ingredient / ha and, if the emulsion is applied, as produced in synthesis, a dose of approximately 1 to 5 kg of active ingredient / ha will be used.

27 A method according to any one of claims 1 to 26, characterized in that one applies a dose of 1.25 kg / ha of acrylamide / acrylic acid-sodium acrylate 30% anionic acid, of very high molecular weight, which reduces the tare, on a species of potato, of 24% of the weight of the tuber to only 8%, ie a reduction of practically 66%.

28 A method according to any one of claims 1 to 26, characterized in that a 40% cationic (co) polymer is applied, and a tare reduction on the potato has been obtained, of 74%.

29 Additives to reduce the tare weight and facilitate the uprooting of so-called "tuber" plants, that is to say underground growth such as beets, sugar or fodder beets, carrots, potatoes, turnips, in general all plants of the “onion” type, and similar tuber plants, characterized in that they comprise at least one of the (co) polymers described in any one of claims 1 to 28.

30 Compositions to reduce the tare weight and facilitate the uprooting of so-called "tuber" plants, that is to say underground growth such as beets, sugar or fodder beets, carrots, potatoes, turnips, in general all plants of the “onion” type, and similar tuber plants, characterized in that they contain an effective dose of at least one flocculating (co) polymer, as described in any one of claims 1 to 29. 31 Agricultural compositions according to claim 30, characterized in that they are emulsions, but also solutions or powders (obtained by synthesis, or powders obtained by drying the reverse synthetic emulsion), and preferably emulsions in an aqueous vehicle of the reverse emulsion obtained by the synthesis of the polymer, itself reversed by mixing with said aqueous vehicle, said aqueous vehicle is preferably water, optionally comprising other additives useful in agriculture.

32 Agricultural compositions according to claim 31, characterized in that in the concentrated state, the compositions will be at the following concentrations: