HU193223B - Method for producing fertilizers of delayed agent releasing improving the water balance of soil too - Google Patents

Abstract

Field of the Invention The present invention relates to a method for producing sustained-release, also nitrogen-containing fertilizer compositions that also contain soil water. According to the invention, at least 1 wt.% Of nitrogen fertilizer is added to clay minerals or rocks containing at least 10 wt.% Of clay minerals, optionally together with one or more other fertilizers, before, during and / or after the addition of the nitrogen fertilizer. at least 0.1 wt.% water soluble, one or more polymers capable of reacting with clay, and the final water content of the mass is adjusted to at least 15 wt.%, and the mass is homogenized and, if desired, cured (dried, diluted and / or dried). formulated or mixed with other active ingredients and / or additives). When urea is used as nitrogen fertilizer, the urea may be reacted with aldehydes before or during the addition of the polymer. -1-

Description

In agriculture, the use of biologically active substances is increasing. Of these, various fertilizers make up the most significant part. It has been known for a long time that fertilizers are applied to the soil in the form of delayed or controlled release formulations. The use of such materials in agriculture would have a multi-directional benefit. In addition to saving the active ingredients (which results in their release at the optimum time interval), it is possible to apply biologically appropriate uptake of the active ingredient in the plants and thus significantly reduce the environmental damage associated with the use of fertilizers (eg contamination of groundwater).

Several methods are known for producing delayed-release fertilizers. According to the oldest method, compounds which can be used as fertilizers are converted into their water-insoluble derivatives and thus released into the soil. Poorly water soluble u.n. "Retarded nitrogen fertilizers include, for example, various condensation products of urea and formaldehyde (U.S. Patent Nos. 3,227,543.3,989,470 and 3,231,363), isobutylidene dicarbamide (Proc. Fert. Soc. 1 (1966), German Patent No. 2,553,939), crotonylidene dicarbamide (Landw. Fr. 17, 148 (1963)), difurfurylidene triureides (Japanese Patent Application Publication No. 75518858). and related compounds (Japanese Patent Application Laid-Open Nos. 75.99.859 and 75.99.860).

There are also known solutions whereby the fertilizer (e.g. urea) particles are coated with different coatings and thereby reduce the dissolution rate of the active ingredient by diffusion inhibition. The preparation of sulfur-coated urea fertilizers is described, for example, in U.S. Patent Nos. 3295950 and 3903333. United States, and U.S. Patent No. 2,451,723. German patent specification. Of the coated fertilizers, sulfur coatings are the cheapest to produce, but the release of the active ingredient is the least controlled here. More favorable results have been achieved with coating compositions containing various clay minerals (zeolite, hydrated aluminum silicate and mica-type clay minerals) and organic film former (British Patent No. 2,127,004). Recently, there has been an increase in interest in various synthetic resin and polymer-coated fertilizers and other agrochemicals (U.S. Nos. 3,223,518 and 3,359,482, Federal Republic of Germany, 2,461,668, and 1,435, respectively). British Patent Nos. 678 and 2,116,960).

According to a third known solution, the fertilizer is applied to or embedded in materials which form a more or less loose chemical bond with the fertilizer molecules or adsorb the fertilizer post-adsorbently. For example, urea is added to the soil in a state applied to various clay minerals such as bentonite (Hungarian Patent Application No. TA-584). These clay minerals form complex bonds with urea (B. K. G. Theng, The Chemistry of Clay-Organic Reactions; Halsted Press (1974)) and other highly polar compounds, thereby delaying its release. However, experience has shown that the effect of clay minerals on delaying release is not satisfactory.

So, are the known formulations more or less effective but the same in kinetics? they modify the release by exerting a delaying effect so that the plants cannot adapt to the more specific needs of the growing season.

In practice, it has not been known so far to provide a fertilizer composition which, while providing a delayed release of the active ingredient, has other beneficial effects, such as improving the water retention capacity of the soil and thereby improving the water balance of the treated soil.

The process of the present invention provides a fertilizer composition which, on the one hand, makes it possible to control the rate of entry of nutrients required by plants over a wide kinetic range and, on the other hand, increases the water retention capacity of the soil.

In our experiments, it has been unexpectedly found that treating triple-layer phyllosilicates (smectites) and / or chain silicates (atapulgites) or rocks containing them with various polymers before, during or after fertilizer application results in products in which the retention of the active ingredient and the resulting products also have water retention properties, thus improving the water content of the treated soil.

The present invention therefore relates to a process for the preparation of a fertilizer formulation with a delayed release, which also improves the water balance of the soil and contains nitrogen. According to the invention, at least 1% by weight of nitrogen fertilizer is added to the clay mineral or to a rock, mining product or artificial mixture containing at least 10% (preferably 25-90%) clay minerals, optionally together with one or more other fertilizers, before, simultaneously with and / or before the addition of nitrogen fertilizer to the clay mineral

-2ί93223 is then added to at least 0 »l% by weight of the water-soluble one or more polymers capable of reacting with the clay, adjusting the final water content of the mass to at least 15% by weight, homogenizing the mass and then drying if desired. in such a case, the composition thus obtained is formulated in a known manner and / or combined with other known agricultural active ingredients and / or excipients.

It is essential for the invention that the fertilizer used as an active ingredient also contains nitrogen.

In the specification and the specification, the term "clay mineral" refers only to triple layer phyllosilicates and chain silicates. The term "rock" refers to all natural and artificial mixtures containing clay minerals as defined above.

Suitable clay minerals are preferably sodium bentonite, activated (i.e. pretreated with calcium salt or other activating agent) calcium bentonite, illite, atapulgite, allevardite or mixtures thereof. The naturally occurring clay minerals are preferably used in the activated state, which means that the swellability of the clay minerals is increased by prior known treatment.

It is essential for the invention to adjust the water content of the mass to at least 15% by weight, preferably 40-65% by weight (in some cases preferably 70-95% by weight). This can be achieved either by starting from clay minerals containing the same amount of water as above, or by adding the fertilizer dissolved in a sufficient amount of water to the clay mineral. The two methods may be combined or water may be added as an aqueous solution of the polymer if desired. The upper limit of the water content of the mass is not a decisive factor and is essentially determined by considerations of economy (the energy demand of any subsequent drying). Preferably, the water content of the mass is adjusted to a minimum edge to ensure good mixability.

The amount of nitrogen fertilizer may be at least 1% by weight, preferably 5 to 30% by weight, based on the weight of the clay mineral. However, urea may be included in the composition of the present invention in an amount of 50-400 wt.% Or more based on the weight of the clay mineral. Nitrogen fertilizers can be any of the known fertilizers, such as urea, ammonium nitrate, ammonium sulfate, multi-nutrient compound and mixed nitrogen fertilizers. In addition to the nitrogen fertilizer, other known fertilizers, such as phosphorus boron fertilizer, trace elements, potassium fertilizer and combinations thereof, may be added to the mass to form combination compositions suitable for the particular need. Other known fertilizers include nitrogen fertilizers retarded in water-insoluble derivatives, such as urea-formaldehyde condensates. These nitrogen fertilizers do not react with clay. Compositions containing both free and bound nitrogen fertilizers release the nitrogen fertilizer by two different mechanisms.

At least 0.1% by weight of the clay mineral water-soluble polymer is added to the mass before, during and / or after the fertilizer or fertilizers are added. The water-soluble polymer is admixed alone or as an aqueous solution.

Preferably, from 1 to 15% by weight of the water-soluble polymer is used, based on the weight of the clay mineral. Preferably, water-soluble polymers are homo- or copolymers containing -COOH, -COCVM * (where M ^{+ is a} monovalent cation), -COONH ₂ , -OH, and / or -C-O-C-C- - as reactive groups. Examples of such polymers include acrylamide homopolymers or copolymers. partially or completely hydrolyzed acrylic, amide homopolymers or copolymers, vinyl acetate homopolymers or copolymers, acrylic ester homopolymers or copolymers, polyvinyl alcohols (such as polyacrylamide, polymethacrylamide, polyacrylic acid, polyacrylamide, hydrolyzate, hydrolyzed acrylamide-acrylic ester copolymers, polyvinyl alcohol-acrylic acid copolymers (polyvinyl alcohols, hydrolyzed polyvinyl acetate), and polyethylene oxides, polysaccharides, and acrylic acid, methacrylamide, methacrylamide and methacrylamide grafted onto a cellulose backbone. The polymers are usually added to the mass in the form of an aqueous solution. the aqueous solution may have a viscosity of 50-500,000 cP / 20 ° C, preferably 500-50,000 cP / 20 ° C. The process preferably employs polymers having a molecular weight of more than 200,000, preferably 500,000 to 14 million.

If urea is used as the nitrogen fertilizer, the first step is to react the clay mineral with urea and then up to 10% of the mixture with one or more aldehydes (e.g. formaldehyde, glutaraldehyde and crotonaldehyde) equivalent to the urea reactive groups present. glyoxal) prior to the addition of the polymer or with the polymer.

In this case, the finished fertilizer composition contains a portion of the urea in the form of a poorly water-soluble derivative reacted with aldehyde. The added aldehyde also occasionally reacts with the polymer present, for example, to partially cross-link acrylamide-type polymers. This reaction further improves the gel structure.

In each case, the two basic requirements for polymers are to be water soluble and to react with clay.

It has been known from previously cited publications that clay minerals form loose chemical bonds with nitrogen fertilizers (primarily urea), and also bind nitrogen fertilizers by physical sorption, thereby slowing down the dissolution of nitrogen fertilizers. In the process according to the invention, this reaction also takes place. However, it is a fundamental difference that the clay mineral is also reacted with a polymer in the process of the invention. The polymer reacts with the active sites of the clay mineral, fixing the structure of the clay mineral (attaching the lamellae lamellae to the polymer chain), thereby forming a stable gel structure. At the same time, the gel formed in the reaction of the clay mineral and the polymer is capable of reversible uptake and release of water, so that it swells appropriately in the microenvironment due to the presence of groundwater. Based on this, the compositions of the invention have the additional effect of improving the water balance of the soil. Thus, according to the invention, dual-function formulations are provided which, in addition to delaying the release of the active ingredient, also have a water-improving effect. The fertilizer components embedded in the clay mineral by loose chemical bonds and physical sorption are no longer released from the stable gel structure of the polymer and clay mineral by reversible water uptake / release, mainly by diffusion. This explains why the formulations of the present invention exhibit a significantly better retardant effect than known but polymer-free formulations containing clay minerals and fertilizers. They are also fundamentally different from polymer coated fertilizers. compositions of the invention. Of the known polymer-coated fertilizers, the active ingredient exits by diffusion through the polymer membrane, but relatively high amounts of polymer (10 to 30% by weight based on the total weight of the composition) are required to form a coherent polymeric coating that can withstand high osmotic pressure. In the process of the present invention, the polymer fertilizer-retarded fertilizer formulations exhibit an approx. an order of magnitude less polymer is required to produce the appropriate retarding effect. It is also obvious that with known water-insoluble polymer-coated fertilizers, no gel structure is formed throughout the particles. Therefore, known polymer-coated fertilizers do not have the additive effect of improving soil water balance.

Wet gels formed of clay minerals, one or more fertilizers and one or more polymers may be used directly, but may be dehydrated if desired. Preferably, the mass is dried at a temperature below 110 ° C. The material thus obtained may be pulverized, granulated, or shaped in a known manner (e.g., agglomerated). However, depending on the application, it is also possible to apply the mass as a liquid (suspension) fertilizer after dilution. Other active ingredients and / or excipients known in the art, such as nitrification inhibitors, trace elements, etc., are known for the mass or dehydrated composition, if desired. may also be mixed, which have their own function in the composition. With this measure, a wide variety of combination formulations can be made to suit the particular requirements.

The invention is illustrated in detail by the following non-limiting Examples. The percentages given in the examples refer to the total weight. The crude bentonite mentioned in the examples has a clay content of 35% by weight and the activated bentonite has a clay content of 75% by weight.

Example 1

40 g of ^methyl wt% moisture, homogenized raw bentonite originating Ratkó Hercegkövesről, was added 6.5% by weight on the dry soda and knead the dough. To the resulting mass containing the activated beptonite is added 25% by weight of urea in the form of a saturated aqueous solution and the mass is kneaded. Subsequently, 2% by weight of a 5% aqueous solution of 5% hydrolyzed polyacrylamide in a weight of about 1 million molar mass is added during intensive kneading. The final water content of the resulting mass reaches 48%. The resulting mass was dried at 60 ° C to constant weight and then powdered.

Example 2

The procedure of Example 1 is followed, except that the aqueous solution of the polymer is added in two steps by first kneading an aqueous solution of 0.8% by weight of polymer, followed by addition of 1% by weight of an aqueous solution of 5% by weight of polymer.

Example 3

The procedure of Example 1 is followed except that the saturated aqueous urea solution is premixed with the solution of po-4193223 limer and the resulting aqueous mixture is kneaded into the clay mass.

Example 4

The crude bentonite of the quality given in Example 1 is activated as described therein. To the activated bentonite was added 5% w / w ammonium phosphate in the form of a saturated aqueous solution and the mixture was homogenized. A saturated aqueous solution of 20% by weight of urea is prepared, 2% by weight of the polymer defined in Example 1 is added to the solution and the aqueous mixture is kneaded into the mass. The resulting mass was dried at 60 ° C to constant weight and then powdered.

Example 5 6% by weight of ammonium phosphate in the form of a saturated aqueous solution and a water content of 36% by weight are added to the activated bentonite B1 (manufactured by Erbslöh Co., Federal Republic of Germany) with a moisture content of 36%. The mixture is kneaded to a homogeneous mass and then 23% by weight of urea and 3% by weight of ammonium nitrate are added as a saturated aqueous solution. The mass is kneaded, then 2% by weight of a 1% by weight aqueous solution of 10 million molar polyacrylamide is added and kneaded vigorously. The resulting mass is dried at 60 ° C to constant weight and then powdered.

EXAMPLE 6 300 g of urea were sprayed into a liter of a 10 wt% aqueous bentonite suspension (containing bentonite of the quality specified in Example 5) under constant stirring. After the urea has dissolved, a 1% by weight aqueous hydrolyzed polyacrylamide solution (average molecular weight: 5 x 10 ⁶ , degree of hydrolysis: 10%) is added to the suspension to give a polymer content of 2% by weight. Stirring is continued until a homogeneous gel is formed from the suspension.

The resulting gel was dried on a sand bath at 50 ° C to constant weight, then ground and sieved to separate a fraction smaller than 0.5 mm.

Example 7

The Hungarian bentonite RVB is activated with soda as described in Example 1. A 10% w / w aqueous suspension of activated bentonite is prepared and 350 g of urea are dissolved in 1 liter of the resulting suspension with constant stirring. To the resulting slurry was added a 4 wt% aqueous solution of hydrolyzed polyacrylamide (average molecular weight: 3 to 5 million, degree of hydrolysis: 5%) to an amount of 12% by weight of the polymer relative to bentonite. In the following, the procedure of Example 6 is followed.

Example 8

90 g of water is added to the blender, and after 10 minutes of intensive homogenization, 10 g of Hungarian bentonite F2 (product of the National Ore and Minerals Company) are added in portions, and the suspension is stirred for another 5 minutes. During this time, the urea _{10 is} completely dissolved. To the resulting suspension was added 30 g of polymer solution (a mixture of 5 g of 2% by weight aqueous glutaraldehyde solution and 25 g of 2% by weight aqueous polyacrylamide solution). Alkaline bentonite suspension starts poly acrylamide and ⁵ the reaction of glutaraldehyde, and a part of the polymer chains are linked. Part of the glutaraldehyde reacts with a part of the urea molecules, respectively

Couples 2o urea molecules to polymer chains. After the reaction was bent, a stable gel was obtained.

Example 9

Example 8 was repeated except that 5 g of distilled water was added to the polymer solution instead of 5 g of glutaraldehyde solution. The gel formed is softer, more plastic, and has a lower crosslink density than the product obtained in Example 830 da.

Example 10

To 200 g of sand soil (95% by weight of sand) was mixed with 2 g of the composition prepared in Example 3. The mixture was saturated with capillary water. The sand soil was initially able to absorb 56 g of water without the addition of the fertilizer composition, which was increased to 61 g by the addition of the 2 g fertilizer composition. To measure the water permeability, the soil sample (weight 200 g) was filled into a 5 cm diameter plastic tube and the amount of water flowing through was measured for 60 minutes under constant water column pressure. The initial sandy soil allowed 197 cm ^{3 of} water to pass; the addition of 2 g of fertilizer composition reduced the amount of water flowing to 98 cm ³ .

⁵⁰ 2 g fertilizer composition was applied 58.5 mg of nitrogen in the sandy soil, mixed with a suitable 58 "5 mg of nitrogen quantities of urea in 200 g of sandy soil as a comparison, and the blends of water ⁵⁵ is led through and measured washed out by the water flowing through all the (organic and inorganic form) nitrogen. 1000 cm ^{3 of} water flushed from the soil treated with urea was 303 mg of nitrogen, while the same amount of water washes only 165 mg of nitrogen from the soil mixed with the composition of the invention. The same amount of water leached 10.3 mg of nitrogen from untreated soil.

The amount of nitrogen washed out by the water flowing through the 60 minutes was as follows:

soil treated with urea: soil treated with fertilizer: untreated soil: 60.6 mg 16.5 mg 2.1 mg Example 11 The experiment described in Example 10 was repeated

except that the fertilizer composition prepared in Example 5 was used. With this composition, 55 mg of nitrogen was introduced into the 200 g of sand soil.

As a result of the mixing of the fertilizer composition, the amount of water taken up by the capillary increased from 56 g to 65 g and the amount of water flowing in 60 minutes decreased from 197 cm ³ to 96 cm ³ .

In a further comparative experiment, 200 g of sand soil was mixed with 55 mg of urea corresponding to nitrogen and the amount of nitrogen washed out with flowing water was measured. The following results were obtained:

Nitrogen washed out with 1000 cm ^{3 of} flowing water:

urea-treated soil: 255 mg fertilizer-treated soil: 93 mg untreated soil: 10.3 mg nitrogen washed out per minute:

soil treated with urea: 51 mg soil treated with fertilizer: 9> 3 mg untreated soil: 2.1 mg

Claims (13)

PATENT CLAIMS A process for the preparation of a sustained release fertilizer formulation containing nitrogen, which also improves the water balance of the soil, characterized in that it is applied to a clay mineral or at least 10 wt% (preferably 25 to 90 wt%) clay mineral, mining product or artificial mixture. at least 1 wt.% nitrogen fertilizer, based on the weight of the clay mineral, optionally together with one or more other fertilizers, at least 0.1 wt.% water-soluble, reactive with the clay, before, during and / or or more polymers are added, while the final water content of the mass is adjusted to at least 15% by weight, the mass is homogenized and then optionally dried and, if desired, the resulting composition is formulated in a known manner and / or other active ingredients and / or excipients. (Priority: September 7, 1984) The process according to claim 1, wherein the clay mineral is used in the form of a mass containing 20 to 70% by weight of water. (Priority: September 7, 1984) The process according to claim 1 or 2, characterized in that from 3 to 50% by weight of nitrogen fertilizer is added to the mass. (Priority: September 7, 1984) A process according to any one of the preceding claims, characterized in that phosphorous fertilizer, potassium fertilizer and / or trace elements are added to the mass as additional fertilizer. (Priority: September 7, 1984) Process according to any one of the preceding claims, characterized in that a further known nitrogen fertilizer, preferably urea formaldehyde condensate, which is retarded in the form of a water-insoluble derivative, is added to the mass. (Priority: April 3, 1985) Method according to any one of the preceding claims, characterized in that from 1 to 15% by weight of water-soluble polymer (s) capable of reacting with the clay mineral is added to the mass. .Priority: September 7, 1984) 7. The process according to claim 6, wherein the reactive groups having a molecular weight of more than 200,000, preferably 500,000 to 14 million molar, are -COOH, -COO ~ M ⁺ (wherein M ^{+ represents a} monovalent cation), -COONH _2. , Homo or copolymers containing OH, and / or <RTI ID = 0.0> C, </RTI> OCO. (Priority: September 7, 1984) A process according to any one of the preceding claims, characterized in that the polymer is subsequently added in successive steps. (Priority: September 7, 1984) Process according to any one of the preceding claims, characterized in that the mass is dried at a temperature of 110 ° C or lower. (Priority: September 7, 1984) 10. A process for the preparation of a sustained release fertilizer composition comprising urea as an active ingredient or one of its active ingredients which improves the water balance of the soil, characterized in that it is for clay minerals or rock containing at least 10% by weight (preferably 25-90% by weight). adding to the mining product or artificial mixture at least 1% by weight of urea, together with one or more other fertilizers, optionally with up to 10% of mono or polyvalent aldehyde in an amount equivalent to the reactive groups of urea, and with or after the addition of aldehyde, one or more polymers capable of reacting with the clay are water-soluble at least 0.1% by weight, with a final water content of at least 15% by weight. g, the mixture is homogenized and then optionally dried and, if desired, formulated in a known manner and / or combined with other known agricultural ingredients and / or excipients. (Priority: April 3, 1985) 11. A process according to claim 10, wherein the aldehyde is formaldehyde, acetaldehyde, furfural, crotonaldehyde, glyoxal and / or glutaraldehyde. (Priority: April 3, 1985) The process of claim 10, wherein the final water content of the mixture is adjusted to 70-90% by weight. (Priority: April 3, 1985) The process according to claim 10, wherein the urea is used in an amount of 50-400% by weight based on the weight of the clay mineral. (Priority: April 3, 1985)