MXPA99002977A - Foil-coated fertilizer for targeted release of nutrients - Google Patents

Abstract

The present invention relates to a foil-coated fertilizer comprising various volumes of a nutrient, the foil-like envelope being a water-soluble polymer, a cellulose material or a textile or a lignocellulose material or a combination of two or more of the above-mentioned materials, the production process and a fertilization method in which the inventive foil-coated fertilizer is applied.

Description

FERTILIZER COATED WITH FILM WITH CONTROLLED NUTRIENT RELEASE The present invention relates to a film-coated fertilizer comprising individually covered volumes of a substance containing a nutrient, the film covering the substance containing the nutrient consists of a water-permeable polymer, a material containing cellulose, a material textile, a lignocellulose material or a combination of two or more thereof and to a process for its preparation and to a method of fertilization in which the film-coated fertilizer according to the invention is used. To improve the effectiveness of fertilizers, the use is generally known as fertilizer fertilizer granules that are coated with a layer of a polymer. The increase in efficiency is caused by the fact that the coated fertilizer releases the substances that act as plant nutrients in a delayed form so that it can be active for a prolonged period. These slow-release fertilizers are described, in Ull anns Enzyklopadie der Technischen Chemie, 5th Ed., 1987, Vol. A10, pp. 363-369, and its advantages are compiled in Fert. Res., 1993, Vol. 35, pp. 1-12.

These shell-core systems, which may also contain fertilizers as an active ingredient, are described among others in EP-A-0 523 098 and EP-A-0 381 181. Other fertilizers that are coated with biodegradable polymers are described, in WO 95/03260. The disadvantages of these granular fertilizers that are provided with a coating are the additional costs in their preparation and storage complications due to the stock of a large amount of different fertilizers. In addition, different thicknesses of cover, which are due to irregular surfaces of the particle and a wide distribution in the size of the particle within the fertilizer to be coated, give rise to a certain impression with respect to the release of nutrients. One possibility of avoiding these disadvantages is to cover the fertilizers, or "substances containing the nutrient, with a film." Thus, for example, US 4,224,048 describes a fertilizer in the form of a tube or pipe consisting of polyvinyl alcohol or a polyvinyl alcohol. polymer that is water-swellable Within this tube, or pipeline, specific amounts of substances containing nutrients are located at regular intervals.The disadvantage of this system is the fact that quantities of substance introduced during the preparation do not separate from each other so that they can move freely inside the pipe, which can result in irregular distribution of the quantities of substances, and once this "pipe" has been introduced into the land, it represents a permanent obstacle when working the ground, since great care must be taken not to damage the * pipe. "In DE-A 40 35 223 an article is described with ingr active ingredient for fertilization, soil conditioning or similar, which is characterized in that the constituents located in this article are embedded or distributed in a biodegradable polymer matrix. The matrices described herein are simply water-impermeable matrices, from which the constituent is only released when the latter are subjected to biodegradation. The result is that before starting biodegradation no constituent is released, but once biodegradation starts, that is, once the matrix shows sufficiently large perforations or holes, the constituent that is present inside is released in a very long period. short, so that the release is no longer controlled and the result can be a particular damage to the plants that are going to be treated by unduly large amounts of active ingredient.

A very similar system in which, again, the active ingredient is released only when the destruction is carried out is described in WO 91/01086. In US 4 845 888 a film for covering agricultural soil on a water soluble synthetic resin which also contains a nutrient or active ingredient is described. Again, this film has the disadvantage that the film will first suffer an incipient dissolution in a medium containing water and, once certain perforations or holes have been formed, the active ingredient or nutrient present will be released within a very short period. In view of the prior art, an object of the present invention is to provide a film-coated fertilizer that allows controlled release of the substances containing nutrients over a prolonged period. The release of nutrients begins immediately after application on or in the soil or substrate through diffusion or osmotic processes and is maintained for a defined period. The soil or substrate is permanently supplied with a sufficiently high and correctly dosed amount of nutrient that is chosen to coincide with the absorption of the plant in question.

In addition, the preparation of this film-coated fertilizer, in particular compared to fertilizers in the form of granules that are provided with a cover, has considerable advantages in terms of costs since complicated process steps are avoided to apply a cover of maximum uniformity to the granules or, when the substance containing the nutrient is used in the form of, for example, a powder, the granulation of the substance containing the nutrient is not necessary. In addition, substances containing normally incompatible nutrients, for example, substances containing ammonium nitrate and urea, can still be used in the form of granules, while their hygroscopicity would normally cause their liquefaction or liquefaction. Accordingly, an object of the present invention is to provide a film-covered fertilizer consisting of one or more volumes individually covered with 3 20 cm or less of at least one nutrient-containing substance, wherein the film covering the volumes of at least one nutrient-containing substance consists of a water-permeable polymer, a cellulose-containing material, a textile, a material of lignocellulose or a combination of two or more of these. This water-permeable polymer is preferably biodegradable.

Another important property of the films that are used according to the invention is that they allow the substance containing nutrients to be released as required in a specific form for the culture. In principle, all commercially available polymers that are water permeable and capable of film formation can be used for the purposes of the present invention. The term "water permeable" used for the purposes of the present invention means that films that can be used in this context and that consist of a water-permeable polymer (hereinafter often referred to as "polymer films") have values of transmission of wet steam exceeding polyethylene. The moisture vapor transmission value of the films prepared from the polymers that can be used according to the invention is preferably above lg / (m.day), measured on a film of 10 μ at 25 ° C and a gradient humidity from 90% to 0% relative humidity. The upper limit of the moisture vapor transmission value of the polymer films that can be used according to the invention is preferably about 100 g / (m x day). Accordingly, polymer films having a particularly pronounced moisture vapor transmission value or which are almost water soluble, for example starch, polysaccharides or even polyvinyl alcohol, can not be used for the purposes of the present invention since these they would unduly dissolve or decompose rapidly in the surrounding medium and thus can not guarantee controlled release for the purposes of the present invention, ie, the longer-term supply of the nutrients over a prolonged period [sic] that matches the requirements of the plants. For the purposes of the present invention '[sic], it is also possible to use laminated films or barrier films containing two or more polymers that meet the above criteria. The polymers that can be used for the purposes of the present invention include in particular the following: aliphatic polyesters, in particular those based on aliphatic dicarboxylic acids having from 2 to 10 carbon atoms, preferably from 4 to 6 carbon atoms, or cycloaliphatic dicarboxylic acids having from 7 to 10 carbon atoms and, preferably those having 8 carbon atoms, for example, malonic acid, succinic acid, glutaric acid, adipic acid, pimelic acid, acelaic acid, sebasic acid, acid fumaric acid, 1,4-cyclohexanedicarboxylic acid, itaconic acid and maleic acid, as described, for example, in EP-A-572 682; polyesters based on aromatic dicarboxylic acids, these generally having from 8 to 12 carbon atoms, preferably 8 carbon atoms, for example terephthalic acid, isophthalic acid, 2,6-naphthoic acid and acid 1, 5-naphthoic; copolyesters containing structural units derived from aliphatic and aromatic carboxylic acids or carboxylic acid derivatives, for example, copolyesters based on adipic acid and terephthalic acid, copolyesters based on fumaric acid and terephthalic acid and those based on succinic acid and terephthalic acid, such as those described, for example, in US 5,446,079 and in the parallel international application WO 92/09654, in DE-A-44 32 161 and in a series of applications by the applicant's own company (P 44 40 858.7, P 44 40 850.1, P 44 40 837.4, P 44 40 836.6, 195 00 757.0, 195 00 756.5, 195 00 755.7, 195 00 754.9, 195 05 185.8 and 195 05 186.6); organic polyacids, for example, polylactic acid, polyhydroxybutyric acid, polyamino acids and polymers of the hydroxypolycarboxylic acids are mentioned below as component (bl) within the scope of the description of the copolyesters (Bl) which can be used according to the invention; polyamides, for example, nylon 6, nylon 66, nylon 12 and nylons 610, 612, and also copolymers based on polyamides; polyvinyl compounds, for example, with base, in each case, polyvinyl compounds, for example, polystyrene, polyvinyl chloride, polyvinylidene chloride, and copolymers of styrene and dienes, for example, butadiene or even styrene / acrylonitrile / butadiene copolymers; poly (meth) acrylates, for example polymethyl (meth) acrylate or polybutyl (meth) acrylate; polycarbonates; cellulose derivatives having a moisture vapor transmission value within the range defined above, for example, cellulose acetate or cellulose acetobutyrate; and mixtures of two or more of these. It should be noted that the molecular weights of the polymers used according to the invention should always be high enough to allow the formation of the films. In a preferred embodiment, the above defined polyesters based on (cyclo) aliphatic dicarboxylic acids and copolyesters containing structural units derived from aliphatic and aromatic carboxylic acids or carboxylic acid derivatives are used, the latter being especially preferred since these polyesters give good films, have a sufficiently high moisture vapor transmission value and are also biodegradable.

The term "biodegradable" as used for the purposes of the present application describes the fact that the films disintegrate after use according to the invention under environmental effects in an immeasurable suitable period of time. It is carried out in hydrolytic and / or oxidative form, but mainly by the action of microorganisms such as bacteria, yeasts, fungi and algae, however, degradation can also be carried out enzymatically, for example, as described in Y.Tokiwa and T. Suzuki in 'Nature' Vol. 270, pp. 76-78, 1977. For the purposes of the present invention it is possible, when the copolyesters used according to a preferred embodiment are used, to select an appropriate ratio between the recurring units from the aliphatic carboxylic acids and those derived from aromatic carboxylic acids. to vary the rate of biodegradation, that is, the point in time by which the polyesters used according to the invention are practically completely degraded. A general rule says that the higher the proportion of recurring units derived from aliphatic carboxylic acids, the higher the rate of biodegradation of the copolyesters. In addition, the high proportion of sections with alternating sequence of recurring units derived from aliphatic and aromatic carboxylic acids or carboxylic acid derivatives, higher the rate of biodegradation of the copolyesters. The films that are used in particular for the purposes of the present invention are those that comprise biodegradable copolyesters (B) having structural units derived from aliphatic and aromatic carboxylic acids or carboxylic acid derivatives and which are obtained by reaction of a mixture composed of: (a) a mixture composed of: (all) 10 to 95 mol% of an aliphatic dicarboxylic acid or a cycloaliphatic dicarboxylic acid or of an ester-forming derivative thereof or of a mixture of two or more thereof. (al2) from 5 to 90 mol% of an aromatic dicarboxylic acid or of an ester-forming derivative thereof or of a mixture of two or more thereof, (al3) from 0 to 10 mol% of a sulfonate containing compound or of a mixture of two or more thereof, the total of the individual mole percentages being 100, (a2) a dihydroxy compound or an amino alcohol or a mixing of two or more thereof, the molar ratio of (a) to (a2) being selected within a range from 0.4: 1 to 2.5: 1, (a3) from 0 to 10% by weight, based on the mixture (a), of a chain extender or a mixture of two or more thereof, and (a4) from 0 to 20% by weight, based on the mixture (a) of a compound having at least 3 groups capable of forming the ester or a mixture of two or more thereof, the recurring units derived from the carboxylic (cyclo) aliphatic and aromatic acid being randomly distributed, and the copolyester having a viscosity number in the range from 5 to 450 g / ml (measured in o-dichlorobenzene / phenol) weight ratio 50/50) at a concentration of 0.5% by weight of the copolyester at a temperature of 25 ° C. In general, the aliphatic dicarboxylic acids which can be used for the preparation of the above copolyester (B) have 2 to 10 carbon atoms, preferably 4 to 6 carbon atoms. The cycloaliphatic dicarboxylic acids that can be used for the. same purpose are those that have 7 to 10 carbon atoms, particularly those that have 8 carbon atoms. However, in principle it is also possible to use dicarboxylic acids having a greater number of carbon atoms, ie having up to 30 carbon atoms. Examples that may be mentioned are: malonic acid, succinic acid, glutaric acid, adipic acid, pimelic acid, azelaic acid, sebasic acid, fumaric acid, 2,2-dimethylglutaric acid, suberic acid, 1,3-cyclopentanedicarboxylic acid, acid 1,4-cyclohexanedicarboxylic acid, 1,3-cyclohexanedicarboxylic acid, diglycolic acid, itaconic acid, maleic acid and 2,5-norbornanedicarboxylic acid, with adipic acid being preferred. The ester-forming derivatives of the aforementioned dicarboxylic acids which can be mentioned are, in particular, the Ci-Cß dialkyl esters, for example, dimethyl, diethyl, dipropyl, dibutyl, dipentyl, and dihexyl ester. The dicarboxylic acids or ester-forming derivatives thereof can be used individually or as a mixture of two or more of these. It is preferred to employ adipic acid or ester-forming derivatives thereof and sebasic acid or ester-forming derivatives thereof, in particular adipic acid or ester-forming derivatives thereof. In general, the aliphatic (cyclo) dicarboxylic acid or ester-forming derivatives thereof represent from about 10 to 95, preferably from about 20 to about 50, and in particular from about 25 to about 35 mol%, in each case based on the total amount of the components (all) a (al3). The aromatic dicarboxylic acids that may be mentioned are, in general, those having 8 to 12 carbon atoms, preferably those having 8 carbon atoms. Examples which may be mentioned are terephthalic acid, isophthalic acid, 2,6-naphthoic acid and 1,5-naphthoic acid, and the ester-forming derivatives thereof. Particular mention may be made of dialkyl Ci-Cß esters, for example, dimethyl, diethyl, dipropyl, dibutyl, dipentyl or dihexyl ester. However, in principle it is also possible to use aromatic dicarboxylic acids having a higher number of carbon atoms. The aromatic dicarboxylic acids or their ester-forming derivatives (al2) can be used individually or as a mixture of two or more thereof. In general, the aromatic dicarboxylic acids or the ester-forming derivatives thereof represent about 5 to about 90, preferably about 50 to about 80, and in particular about 65 to about 75% mol.. , in each case based on the total amount of the components (all) to (al3).

The sulfonate (al3) -containing compound employed is generally an alkali metal salt or alkaline earth metal salt or a dicarboxylic acid containing sulfonate or its ester-forming derivatives, preferably the alkali metal salts of 5-sulfoisophthalic acid or mixtures thereof. of these, in particular the sodium salt. The sulfonate-containing compound (al3) represents from 0 to about 10, preferably from 0 to about 5 and in particular about 3 to about 5 mol%, in each case based on the total content of the components (all) a ( al3). The compounds containing sulfonate can be used individually or as a mixture of two or more thereof. According to the invention, the component (a2) used is a dihydroxy compound or an amino alcohol or a mixture of two or more of these. In principle, all known diols or amino alcohols for the preparation of the esters can be used. However, in general, the alkanediols (a21) having from 2 to 10 carbon atoms, preferably from 4 to 6 carbon atoms, or cycloalkanediols having from 5 to 10 carbon atoms, the polyether diols (a22), that is, dihydroxy compounds containing ether, and amino alcohols (a23) having from 2 to 12 carbon atoms, preferably from 2 to 4 carbon atoms, and amino cycloalcols having from 5 to 10 carbon atoms are used. Examples which may be mentioned are ethylene glycol, 1,2-, 1,3-propanediol, 1,2-, 1,4-butanediol, 1,5-pentanediol, 2,4-dimethyl-2-ethylhexan-1, 3-diol, 2,2-dimethyl-1,3-propanediol, 2-ethyl-2-butyl-1,3-propanediol, 2-ethyl-2-isobutyl-1,3-propanediol, 2,2, 4- trimethyl-1,6-hexanediol, in particular ethylene glycol, 1,3-propanediol, 1,4-butanediol and 2,2-dimethyl-1,3-propanediol (neopentyl glycol); cyclopentanediol, 1,4-cyclohexanediol, 1,2-, 1,3- and 1,4-cyclohexanedimethanol and 2,2,4,4-tetramethyl-1,3-cyclobutanediol; Diethylene glycol, triethylene glycol, polyethylene glycol, polypropylene glycol and polytetrahydrofuran, in particular diethylene glycol, triethylene glycol and polyethylene glycol, or mixtures thereof, or compounds having a variable number of ether units, for example, polyethylene glycol containing propylene units and which can be obtained for example, by polymerization of first ethylene oxide and subsequently propylene oxide, following the methods known per se. The molecular weight (Mn) of the polyethylene glycols that can be used is, as a rule, about 250 to about 8000, preferably about 600 to about 3000 g / mol; 4-aminomethylcyclohexanemethanol, 2-aminoethanol, 3-aminopropanol, 4-aminobutanol, 5-aminopentanol, 6-aminohexanol; aminocyclopentanol and amino cyclohexanol; and mixtures of these. The dihydroxy compounds or amino alcohols can be used individually or as a mixture of two or more thereof. The molar ratio of (a) to (a2) is generally selected in a range from about 0.4: 1 to about 2.5: 1, preferably in a range of about 0.5: 1 to about 1.5: 1, more preferably to about 0.5: 1 to about 1.2: 1 in particular in a range from about 0.5.1 to about 1: 1. The molar ratios of (a) to (a2) in the isolated copolyester (if appropriate after the desired amount of the excess component (a2) has been removed) are about 0.4: 1 to about 1.5: 1, preferably about 0.5: 1 to about 1.2: 1, in particular about 0.5: 1 to about 1: 1. The chain extenders (a3) that can generally be used are all the chain extenders that are conventional for the preparation of the polyesters. If these are used, they represent about 0.01 to about 10, preferably about 0.05 to about 5, more preferably about 0.07 to about 3, in particular about 0.1 to about 1% by weight, in each case based on the mixture (al). The following may be mentioned among the chain extenders employed: diisocyanates, for example toluene-2,4-diisocyanate, 2,6-toluene diisocyanate, 4,4'-diisocyanate and 2,4'-diphenylmethane, 1, 5 naphthylene diisocyanate, xylylene diisocyanate, hexamethylene diisocyanate, isophorone diisocyanate and methylenebis (4-isocyanatocyclohexane), in particular hexamethylene diisocyanate; the trifunctional isocyanate compounds which may contain isocyanurate and / or biuret groups of a functionality of not less than 3; divinyl ethers, for example, 1,4-butanediol divinyl ether, 1,6-hexanedioldivinyl ether and 1,4-cyclohexanedimethanol divinyl ether; and 2, 2'-bis oxazolines of the general formula (I) The latter are usually obtained by the process described in Angew Chem Int. Edit., Vol. 11 (1972), pp 287-288. Especially preferred bisoxazolines which may be mentioned are those in which R is a single bond, a (CH2) q-alkylene group where q = 2, 3 or 4, such as methylene, ethane-1,2-diyl, propan- 1,3-diyl, propan-1, 2-diyl, butan-1,4-diyl or a phenylene group. Particularly preferred are 2,2 '-bis (2-oxazoline) bis (2-oxalzolinyl) methane, 1,2-bis (2-oxazolinyl) ethane, 1,3-bis (2-oxazolinyl) propane, 1,4- bis (2-oxazolinyl) butane, 1,4-bis (2-oxazolinyl) benzene, 1,2-bis (2-oxalinyl) benzene and 1,3-bis (2-oxazolinyl) benzene. Chain extenders (a3) can also be used as a mixture of two or more of these. In addition, it is possible to employ a compound having at least 3 groups capable of forming ester (a4) or a mixture of two or more of these, ie, if present, in an amount from about 0.01 to about 20, preferably from about 1 to about 10, especially preferably from about 3 to about 7, and in particular from about 3 to about 5% by weight, in each case based on the mixture (a). The compounds which are used as the compounds (a4) preferably contain 3 to 10 functional groups which are capable of formation of the ester bond. Especially preferred compounds (a4) have from 3 to 6 functional groups of this type in the molecule, in particular from 3 to 6 hydroxyl groups and / or carboxyl groups. The tri- and / or tetrafunctional dicarboxylic acids or derivatives thereof are particularly preferably used. Examples which may be mentioned are: tartaric acid, citric acid, malic acid, trimethylol propane, trimethylol ethane, pentaerythritol, polyether triloles, glycerol, trimesic acid, trimellitic acid, trimellitic anhydride, pyromellitic pyromellitic dianhydride and hydroxyisophthalic acid. By adding chain extenders (a3) and / or the compounds (a4) it is possible to modify, for example, the viscosity in the melt, the limiting viscosity number or the molecular weight in the desired form, ie, increase in correspondingly the number of limiting viscosity and molecular weight compared to polyesters to which none of the chain extenders (a3) and / or compounds (a4) have been added and thus vary the mechanical properties of the polyesters for adapt the specific use. In one embodiment, films comprising biodegradable copolyesters (Bl) having structural units derived from aliphatic and aromatic carboxylic acids and carboxylic acid derivatives, obtainable by reaction of a mixture composed of: (a) a mixture composed of: ( all) from 10 to 95% mol of an aliphatic dicarboxylic acid or of a cycloaliphatic dicarboxylic acid or of an ester-forming derivative thereof or of a mixture of two or more thereof. (al2) from 5 to 90 mol% of an aromatic dicarboxylic acid or of an ester-forming derivative thereof or of a mixture of two or more thereof, (al3) from 0 to 10 mol% of a compound containing sulfonate or a mixture of two or more thereof, the total of the individual mole percentages being 100, (a2) a dihydroxy compound or an amino alcohol or a mixture of two or more thereof, the molar ratio being ( al) to (a2) selected within a range from 0.4: 1 to 2.5: 1, (a3) from 0 to 10% by weight, based on the mixture (al), of a chain extender or a mixture of two or more thereof, and (a4) from 0 to 20% by weight, based on the mixture (a) of a compound having at least 3 groups capable of forming the ester or a mixture of two or more thereof , (bl) from 0.01 to less than 50% by weight, based on the mixture (al), of a hydrocarboxylic acid (bl) which is defined by the following formula lia or Ilb.

HO- [C (O) O] pH (Ha) where p is an integer from 1 to 1500 and r is 1, 2, 3 or 4, and G is a phenylene group, a group E2) n ~ r where n is an integer of 1, 3, 4 or 5, a -C group (R) HCH2- a group -C (R) HCH2, where R is methyl or ethyl, or a mixture of two or more of these, the recurring units from the (cyclo) aliphatic and aromatic carboxylic acid being randomly distributed, the copolyester with a viscosity number in the range from 5 to 450 g / ml (measured in o-dichlorobenzene / phenol (50/50 weight ratio) at a concentration of 0.5% by weight of the copolyester at 25 ° C). In the above formula p is preferably 1 to about 1000; r is preferably 1 or 2; n is preferably 1 or 5. The content of hydroxycarboxylic acid (bl) in the reaction mixture preferably represents about 0.1 to 30% by weight, based on the mixture (al).

The substances which are preferably used as hydroxycarboxylic acid (bl) are glycolic acid, D-, L-, D, L-lactic acid, β-hydroxyhexanoic acid, cyclic derivatives thereof, such as glycolide (1,4-dioxan- 2, 5-dione), D-, L-, dilacturo (3,6-dimethyl-l, 4-dioxan-2, 5-dione), p-hydroxybenzoic acid and oligomers and polymers thereof, such as acid 3-polyhydroxybutyric acid, polyhydroxyvaleric acid, polylactide (for example, available under the name EcoPLA® (Cargill)), and a mixture of 3-polyhydroxybutyric acid and polyhydroxyvaleric acid (the latter available from Zeneca under the name Biopol®), being used the low molecular weight and cyclic derivatives defined above. Of course, it is also possible to use mixtures of two or more of the aforementioned hydroxycarboxylic acids. In addition, the use of cyclic derivatives of the above-described hydroxycarboxylic acids (bl) in the reaction with the biodegradable copolyester used according to the invention gives, in a manner known per se, by means of a so-called polymerization reaction with an opening ring "copolyesters of the type defined above containing block structures composed of the copolyester (b) used according to the invention which are joined to each other in each case of at least one hydroxycarboxylic acid unit (b) ring-opening polymerization "see, Encyclopedia of Polymer Science and Engineering, Vol. 12, 2nd Ed., John Wiley &Sons, 1988, pp. 36-41). The copolyesters which are especially preferably used within the scope of the present invention have the following composition related to the components (all), (al2) and (a2), where it should be taken into consideration that these copolyesters can not only contain sulfo groups , but may also contain the chain extenders and / or compounds defined as components (a3) and (a4). The data in brackets that follows the components in question corresponds to the amount of these components in mol percent: terephthalic acid (75) adipic acid: 25) neopentyl glycol (100), terephthalic acid (70) adipic acid (30) butanediol ( 100), terephthalic acid (70) - adipic acid (25) - isophthalic acid (5) - neopentyl glycol (100), terephthalic acid (60) - adipic acid (40) butanediol (100). The copolyesters which are used according to the invention are characterized by the following peculiarities: They have a viscosity index in the range of about 5 to 450 g / ml, preferably about 100 to about 350 g / ml and, in particular, about 200 to about 350 g / ml, in each case measured in o-dichlorobenzene- phenol (50/50 weight ratio) at a concentration of 0.5% by weight of the copolyester at a temperature of 25 ° C. With respect to other details about the dicarboxylic (cyclo) aliphatic acids, aromatic dicarboxylic acids, diols and / or amino alcohols that can be used within the scope of the present invention and other components (a3), (a4) and (Bl), reference is made to the patent applications of the company - of the applicant mentioned at the beginning when the prior art is explained, and to US 5 446 079 and the parallel application WO 92/09654, the content with respect to the copolyesters described herein and their preparation are incorporated in the present application by reference. Furthermore, it is possible, if appropriate, to use a cellulose-containing material, a textile material or a lignocellulose material as a film material in combination with the water-permeable polymer described in detail in the foregoing. Cellulose-containing materials usable as films according to the invention include: celluloses of paper and celluloses of synthetic fiber, where the raw materials for paper celluloses can be obtained from wood, straw, reed, bamboo and bagasse. The celluloses of synthetic fibers that can be used are those based on synthetic cellulose fibers or synthetic ether and cellulose ester fibers. Further details regarding the cellulose-containing materials that can be used according to the invention are described in Ullmans Encyclopaedia der technischen Chemie, 4th edition, vol. 17 (1979), pp. 531-631, under the entry 'papier', the content of which, with respect to the cellulose-containing materials described herein, is incorporated in its entirety in the context of the present application.It is also possible to use a textile material as a film According to the invention, the term "textile material" as used for the purpose of the present application includes all materials in the form of a fabric or mesh that are based on textile fibers in the form of felts, fabrics and mats. . The textile fiber materials which can be used according to the invention for preparing the textile material which can be used according to the invention are natural fibers, such as cotton and kapok, and in particular synthetic fibers, such as Examples are fibers made from regenerated cellulose, cellulose acetates, alginates and polyisoprenes, synthetic fibers such as those prepared from the above-defined water-soluble polymers, but also polymer fibers which are not impervious to water according to the definition herein. invention, such as, for example, polyethylene and polypropylene. It is also possible to use a lignocellulose material. The rate at which nutrients are released from the film-coated fertilizers according to the invention can be controlled not only by selecting the film material used, but also by the thickness of the films, which is generally from about 500μ or less , preferably about 200 [lacuna] or less, and in particular about 10 to about 100μ. Depending on the purpose, culture time and vegetation, it is further essential according to the invention that the volume of the nutrient-containing substance contained in the film-coated fertilizer represents about 20 cm or less, preferably about 10 cm or less , more preferably about 3 cm or less and, particularly preferably about 0.05 cm 3 to about 2 cm 3, since the arrangement of these small amounts of nutrient-containing substance guarantees the controlled release of the substance containing nutrients in such quantity that there are no unduly high loads or loading of substrates and associated damages. The lower limit for the coated volumes according to the invention is about 0.01 cm 3, preferably about 0.05 cm 3. The substances containing nutrients that are present in the film-coated fertilizer according to the invention can be present in the form of powder, granules, paste or liquid. Substances that contain suitable nutrients that can be used within the scope of the present invention are, in particular, organic or mineral fertilizers such as those described, for example, in Ullmans Encyclopedia of Industrial Chemistry, 5th ed. 1987, Vol. A10, pp. 323-431 (see, in particular, chapters 2.1 and 4). Suitable fertilizers are, for example, direct and compound fertilizers, which consist, individually or, if appropriate, in combination, of nutrients such as nitrogen, potassium or phosphorus, if appropriate in the form of their salts. Examples are NP, NK, PK and NPK fertilizers, pure nitrogen-containing fertilizers such as nitrochalk, ammonium sulfate, ammonium nitrate sulfate and urea, and also slow-release fertilizers, particularly urea based, for example, isobutylideneurea, crotonylidene diurea and the urea / formaldehyde condensate.

It is also possible to use other plant nutrients and also trace elements which, in addition to the main components mentioned above, contain minor amounts of compounds consisting of Mg, Ca, S, Fe, Mn, Cu, Zn, Co, Mo and / or B, that is, normally in smaller quantities as specified by the requirements of the Düngemittelverordnung [Fertilizers Act]. The substances that contain nutrients can be used individually or as a mixture of two or more of them. In addition to the substance containing nutrient or the mixture of two or more thereof, the product may also contain other additives, for example, nutrient inhibitors as described, for example, in DE-A 41 28 828, DE 195 03 827.4 and DE 196 31 764.9 and in the prior art cited in these publications, in particular pyrazoles or pyrazole derivatives, growth regulators and active ingredients used in the protection of crops, for example, fungicides, insecticides and herbicides. The present invention further relates to a film-coated fertilizer, the latter being in the form of a plurality of individually coated volumes of 20 cm or less of at least one nutrient-containing substance that are arranged in succession in one or more parallel rows . This means that the film-coated fertilizer according to the invention can be, for example, in the form of a 'bead cord', a plurality of these, 'bead cords' arranged side by side, but also individually, after the structures described above have been cut in the interstices that are located between the volumes using suitable cutting devices. The present invention also relates to a process for the preparation of a film-coated fertilizer according to the invention which consists of the following steps: a) feeding, in an application device, at least one first and at least one second film that contains a water-permeable polymer as defined above; b) applying, by means of the application device, a plurality of volumes of 20 cm3 or less of at least one substance containing a nutrient to the at least one first film in such a form that the volumes are separated by interstices; c) joining the at least one first and the at least one second film in the interstices located, between the volumes in such a way that each of the volumes is covered individually, whereby a fertilizer covered with film is obtained.

For the purposes of the process according to the invention, the films are fed to the application device by means of a conventional feeder device, for example, a roller. As soon as the film of the water-permeable roller is located in the application device for applying the nutrient-containing substance, an adequate amount of these substances is applied to the at least one first film, it being essential that the applied volumes are at each case separated by interstices. In one embodiment, the surface (s) within the application device, generally one or more preferentially heated metal surfaces to which the 'at least one first film, the at least one second film or at least one first and the at least one second movie is, or are, fed and in which the respective film (s) within the Application device is, or are, located during the application process, is designed in such a way that it is or are provided with recesses. In general, the areas of the fed film (s) covering the recesses are then molded into these recesses by means of a pressure source, i.e., a superatmospheric pressure source or a vacuum source, preferably a vacuum source. The recesses of the aforementioned surface (s) preferably have at least one volume corresponding to half the volume of the substance containing the nutrient to be applied. If the volume of the recesses with which the first film is provided corresponds to half the volume of the substance containing the nutrient, the at least one second film of preference is also fed to a surface within the application device, or is located, during the application process on such a surface that is provided with recesses whose volumes correspond to at least one medium of the volume of the substance that contains the nutrient. Of course, the process according to the invention can also be carried out in such a way that the surfaces on which the at least one first film is located, the at least one second film or the at least one first and the at least one second film within the application device is provided [sic] with recesses whose volumes are greater than half the volume of the substance containing the nutrient to be applied and corresponds, for example, to the volume of the substance containing the nutrient which will be applied, in which case the second film can be provided with proportionally smaller recesses or without additional recesses when applied to the first film.

In this way, it is only essential that the films described herein that cover the fertilizer form a total volume in which the amount of fertilizer fed can be accommodated. After the feeding and application processes have finished, the previously defined films are joined together in the interstices located between the volumes, which is generally carried out by adhesive bonding or by welding the films by the usual methods. In addition, the two films can also be joined together by applying vacuum, or by an electrostatic charge. In another embodiment of the present invention, the at least one first and the at least one second film each are fed to a roller whose surfaces are provided with recesses. The volume of each of the recesses corresponds to half the volume of the substance containing nutrient applied. The devices that are preferably used are press rolls, ie machines with a plurality of cylinders, as already defined, which are optionally provided with heatable recesses that are usually arranged one on top of the other, or side by side. In general, the procedure is as follows: In each case at least one first and at least one second film are fed from two sides of the cylinder whose surface is provided with suitable recesses. The films are then introduced into the recesses by means of a suitable device, for example, a vacuum source. Before loading with the substance containing the nutrient, the films come into contact with each other at a point of the device used and are joined together on one side. A suitable amount (volume) of the substance containing the nutrient is then fed, the two films are brought into contact again with each other once the addition of the substance containing the nutrient is finished and again they are joined together for example by adhesive bond, by welding, applying a vacuum or applying an electrostatic charge. Furthermore, the invention relates to a process for the preparation of a film-coated fertilizer as defined above, which consists of the following steps: a) feeding, in an introduction device, at least one film that is in the form of a tube and consisting of a water-permeable polymer; b) introducing, by means of the introduction device, a plurality of volumes of 20 3 co less than at least one substance containing nutrient in the at least one film in the form of a tube, in such a way that the volumes are separated by the interstices; c) closing, preferably by sealing or welding, the at least one film in the form of a tube in the interstices located between the volumes in such a way that each of the volumes is covered individually, by means of which a covered fertilizer is obtained with a movie If it is desired to apply the film-covered fertilizer in the form of individual covered volumes of the nutrient-containing substance, the film-covered fertilizer obtained in step c) of the processes in. The matter can be separated by cutting or drilling the fertilizer in the interstices located between the volumes by means of a cutting or perforating device to give fertilizers covered with individual films, each of which contains a volume of approximately 3 20 co less than the substance that contains the nutrient; in the case of drilling, the separation of the units of covered fertilizer takes place when the fertilizer is applied. The process according to the invention can be carried out continuously or in batches. The present invention also refers to a film-coated fertilizer that can be prepared by a process comprising the following steps: a) feeding, in an application device, at least one first and at least one second film containing a permeable polymer the water; b) applying, by means of the application device, a plurality of volumes of 20 cm or less of at least one substance containing the nutrient to the at least one first film in such a form that the volumes are separated by interstices; c) joining the at least one first and the at least one second film in the interstices located between the volumes in such a way that the volumes are covered individually, and a fertilizer covered with film that can be prepared by a process consisting of the following steps: a) feeding, in an introduction device, at least one film that is in the form of a tube and comprising a water-permeable polymer; b) introducing, by means of the introduction device, a plurality of volumes of 20 3 cm or less of at least one substance containing nutrient in the at least one film in the form of a tube, in such a way that the volumes are separated through interstices; c) closing, the at least one film in the form of a tube in the interstices located between the volumes, in such a way that each of the volumes is individually covered, thereby obtaining a fertilizer covered with film. The present invention further relates to a method of fertilization in which the film-coated fertilizer according to the present invention, or a film-covered fertilizer prepared according to the present invention is applied to, mixed with or worked on. the soil or the substrate.

Claims (4)

1. A film-covered fertilizer consisting of 3 one or more individually covered volumes of 20 cm or less of at least one substance containing the nutrient in the form of a powder, a paste or a liquid, the film covering the volumes of when less a substance that contains the nutrient consists of a water-permeable polymer.

2. The film-coated fertilizer as claimed in claim 1, wherein the water-permeable polymer is biodegradable.

3. The film-coated fertilizer as recited in claim 1 or 2, wherein the film-covered fertilizer is in the form of a plurality 3 of individually covered volumes of 20 cm or less of at least one nutrient-containing substance, which are arranged in succession in one or more parallel rows.

4. A process for the preparation of a film-coated fertilizer as mentioned in any of the preceding claims, which consists of the following steps: a) feeding, in an application device, at least one first and at least one second film, such as is defined in claim 1 or 2; b) applying, by means of the application device, a plurality of volumes of 20 cm or less of at least one substance containing nutrient to the at least one first film, in such a manner that the volumes are separated by interstices; c) joining the at least one first and the at least one second film in the interstices between the volumes, in such a way that each volume is covered individually, by means of which a film-covered fertilizer is obtained. The process, as mentioned in claim 4, wherein the at least one first film, the at least one second film or the at least one first and the at least one second film are fed in each case to at least one surface arranged within the application device and provided with recesses, and wherein the areas covering the recesses, of the at least one first film, of the at least one second film or of the at least one first and the at least one second film, they are molded in the recesses by means of a pressure source. The process as mentioned in claim 4 or 5, wherein the at least one first and the at least one second film each are fed to a cylinder whose surfaces are provided with recesses. The process as mentioned in any of claims 4 to 6, wherein the at least one first and the at least one second film, after being loaded with at least one substance containing the nutrient, are joined together by applying a vacuum, applying an electrostatic charge, by adhesive bonding or by welding the films in the interstices located between the volumes. A process for the preparation of a film-coated fertilizer as mentioned in any of claims 1 to 3 which consists of the following steps: a) feeding, in an introduction device, at least one film that is in the form of a tube, as defined in claim 1 or 2; b) introducing, by means of the introduction device, a plurality of volumes of 3 cm or less of at least one substance containing nutrient in the at least one film in the form of a tube, such that the volumes are separated by interstices; c) closing, the at least one film in the form of a tube in the interstices located between the volumes, in such a way that each of the volumes is covered individually, by means of which a film-covered fertilizer is obtained. The process as mentioned in any of claims 4 to 8, which further comprises the following step d): d) cutting or perforating the film-covered fertilizer in the interstices located between the volumes by means of a cutting or perforating device. A method of fertilization wherein a film-coated fertilizer as recited in any one of claims 1 to 3, or a film-covered fertilizer prepared by means of a process as recited in any of claims 4 to 9, is applied to , mix with or work on the soil or a substrate.