Controlled release products based on urea

 

(57) Abstract:

The invention relates to agriculture, namely, to products on the basis of urea, which are released during the controlled period of time, and can be used for fertilizing plants and food additives for animals. The invention concerns a product with a controlled release formulation comprising particles or granules consisting entirely or mainly of urea or containing urea at its outer surface or on them, and water resistant coating on the particles of vzaimopronikayut polymer network. The coating consists of a reaction product of urea and isocyanate interacting with urea, and the reaction products of an excess of isocyanate over it, and reacted with urea, alkyd resins and oils containing at least one double bond. The invention also includes variant of the product controlled release method of processing particles to obtain a product, and how the plants and the method of feeding ruminants, including the stage of introduction of the product into the soil and feed ration. The invention provides improved product quality due to constant SV) in the rumen during the period of time from 20 to 24 hours. 5 C. and 15 C.p. f-crystals, 8 PL.

Cross-reference

This application is a partial continuation of the parallel application serial No. 09/286931 filed April 6, 1999.

The technical field to which the invention relates.

The present invention relates to products on the basis of urea, which are released during the controlled period of time, and to methods for their preparation. In the invention, particular attention is paid to controlled release of food additives on the basis of urea for animals and controlled release fertilizers for plants urea-based.

Prior art

Urea in the form of particles is an excellent and economical source of nitrogen to stimulate plant growth. Unfortunately, it quickly dissolves in water. For example, during the spring rains the water-soluble nutrient plants quickly washed away, resulting in (a) is called the reduced effectiveness of its actions in the form of plant feeding, (b) potentially induced its cytotoxicity towards plants, (C) stimulated feeding movement to groundwater and local water bodies and rivers and their zahradkarske with speed, approximately equal to the speed of its capture by plants to minimize phytotoxicity and for maximum efficiency. Improved control release was achieved primarily for nitrogen in form of urea essentially through interaction with the aldehydes with the formation of such insoluble products, such as modelinformation, which chemically break down in the soil before the nitrogen becomes available for recycling plants. Another way is physical coating fertilizer granules hardened insoluble in water and melt. As the coatings have been used in a variety of materials, including sulfur, paraffin wax, vegetable oil and plastic. These coatings must collapse under the action of erosion, internal elasticity of steam, microbes or friction before the feeding becomes available.

Urea in granular form is also excellent and economical source of non-protein nitrogen (NPN) for use as an additive in food ruminants, such as cows, cattle, sheep, goats, etc., Microorganisms found in the rumen or first stomach of ruminants, allow the connection, such as urea, are initially converted to ammonia by the action of enzymes produced by rumen microorganisms, which are then disposed of ammonia for the synthesis of amino acids of the protein, which can be either hydrolyzed by the digestive system of the scar.

The ability of ruminants to utilize connection NPN as indirect sources of protein has important economic consequences. One pound (453,6 g) of urea is equivalent to the nitrogen content of more than five pounds (2268,0 g) food high in protein, such as soy flour. Relative price per unit of nitrogen soy flour is much more expensive than urea. Consequently, there is a strong incentive for replacing part or even the entire plant protein for ruminants in connection NPN.

Unfortunately the number of connections NPN, which can swallow a ruminant, is extremely limited. Ammonia is produced by splitting the connection NPN during the fermentation process after eating, can be transported into the bloodstream through the wall of the rumen. If you experience high levels of ammonia in the blood changes the acid-base balance of the blood that affects the Central nervous system. Early toxic effects predrilling cases, there may be convulsions, and death.

Various attempts have been made to limit the concentration of ammonia in the rumen so that it has been possible to use more connections NPN in the daily diet. Among them are a few suggestions for the preparation of the composition or mixing urea with some kinds of water-insoluble polysaccharides and/or interaction of urea by the above methods for controlled release of NPN in the rumen with the speeds at which is stored the tolerance of animals.

Examples of previous achievements in the creation of food additives controlled release in the rumen are the U.S. patents 3873733 and 4393082, and U.S. patent 4711659 and 4804403 are examples of previous achievements in the creation of structures for the plants controlled release.

Although commercial success in both the fertilizing plants, and food additives for ruminants, to some extent has been achieved, a major priority is the creation of products for feeding urea-based, which is not soluble in water, saliva and gastric juices and have the best time controlled speed of release.

A brief statement of the substance of the invention

The aim of the present invention is the provision of a more reliable and better made products based on urea, having a controlled rate of release over a preselected period of time. The application is in General applicable to particles, comprising in whole or in part urea and/or particles containing urea at its outer surface or on them, regardless of their application. However, the invention relates primarily to a more reliable and better made podkormochnye NPN.

The specific objectives of the invention is to provide a fertilizer for plants, urea-based, having essentially a constant rate of release of plant food in the soil over a long period of time, for example from 30 to 120 days, and (b) feed additive for ruminants on the basis of urea, having a constant rate of release of NPN in the rumen within twenty - to twenty-four hour period of time.

In accordance with the invention, the improvement is achieved by converting the surfaces of the particles on the basis of urea in vzaimopronikayut polymer mesh covering included the reaction products of urea and MDI, and simultaneous polymerization by condensation and free radical polymerization of the isocyanate, alkyd resins having a double bond in each repeating part and oils such as dehydrated castor oil or Tung oil having double bonds interacting with the double bonds of an alkyd resin, and ourselves.

Thus on the particle shell is formed from a three-dimensional vzaimopronikayut polymer network with a very high density three-dimensional cross-linkage.

Hydrophobic To increase stability during manipulation can be optionally applied to the outer coating of wax.

In the target coating all components are chemically bonded to each other and are chemically bonded with the surface of the particles, which leads to the creation of a result, more reliable and better made products.

The surface of the obtained particles are durable, dense, resistant to shock and wear, uniform, dust-free and non-sticky. The particles form a free current, essentially dust-free and easy to use products based on urea.

In the end products, the ratio of baits to control agents is very high, controlled release is achieved at minimum cost, and the products are economical in use.

In addition, the method of obtaining the products is economical, practical and easy.

This method may be performed either separately or as a final step of the process of production of urea, either as a continuous process or as a periodic process. In accordance with the present invention the particles of urea served in suitable apparatus, for example in a rotary mixer, cover the drum, fluidized bed or the like, to create a mobile mass of the particles, Wnuk each particle from time to time appears on the surface of the mass for applying liquid or fluid MDI and liquid or fluid mixture of an alkyd resin, oil, initiator of free radical formation and catalyst and/or promoter, causing the transformation of the surfaces of the particles in the above-described coating of vzaimopronikayut polymer network. The method is very effective and inexpensive to perform in practice and creates a product based on urea cost-effective controlled-release that has the characteristics and traits that are desirable for the industry.

These and other objectives, features and advantages of the invention will become apparent to experts in this field from the following detailed description.

Detailed description of the best mode of carrying out the invention

The following is a detailed description of the preferred options for the implementation of the invention, representing, as at present, according to the applicants, the best way of carrying out the invention.

The invention in its preferred implementation is applicable for controlling the time of release fertilizers, including urea, in whole or main part. However, the source material may be any chemical or chemical compound, or compounds, including individual particles or granules containing mausi these variations.

In practice, according to the invention, the particles should preferably have a high degree of uniformity or regularity and a small surface area per unit weight. Particles of uniform shape and size and having a small surface area per unit weight, as it turned out in General, most effectively covered by minimum number of covering materials.

The method of the invention can be effectively done by creating a mobile mass of the particles by any of various mechanisms, including rotary mixers, rotary drums, fluid layers, rotating the trays, the contactors in the form of a falling film, conical blenders and mixers conveyors. Devices attach to the particle mobility and induce rotation, Galatenko or the motion of free falling particles in the mass, so that the surface of each particle at least intermittently exposed to local deposition of material, such as a covering material which can be applied to the particles in the liquid, liquid form or in powder form by pouring, spraying or mixing.

Drum and tray device for coating are widely used in various industrial processes, and they are well Sarich processes.

In accordance with the present invention of the mobile mass of particles is treated with a polyfunctional isocyanate which reacts with urea on the surface of the particles with the formation of biureta, i.e., condensation products of urea with isocyanate. The reaction, which can be expressed as

R-NCO+H2NCONH2R-NHCONHCONH2

allow the isocyanate group to form a chemical bond on the surface of the urea. This reaction increases the adhesion between the coating and the substrate particles and provides the first barrier to water on the surface of the granules of urea.

The number of MDI, applied to the particles is in excess relative to the target to interact with urea contained on the surface of the particles, and the excess is sufficient to maintain the following described reaction, and preferably is from 5 - to 10-fold and more preferably from 6 - to 8-fold relative to the amount required to transform the surface of the particles in biuret. The polyisocyanates that are preferred in the practice of the invention are polymeric diisocyanates having more than two functional groups, preferably the polymer given aliphatic or aromatic, linear or branched, substituted or unsubstituted, saturated or unsaturated isocyanates having more than two isocyanate functional groups.

MDI can be PAPI polymeric MDI from Dow Chemical Co., or Rubinate M polymeric MDI from ICI Polyurethanes or MONDUR MR-200 polymeric MDI from Voeg, Inc. HDI can be DESMODUR polymeric HDI XP7100, N3300 or N75BA from Voeg, Inc. In the practice of the invention is also applicable HDI monomer, such as DESMODUR H from Voeg. Polymeric diisocyanate should have a functionality in the range of from more than 2.0 to about 3.5, and the NCO content in the range from approximately 15% to approximately 35%.

To facilitate the reaction of MDI with urea can be applied to the catalyst based on tin, such as T1 or T12, supplied by Air Products Co., or a catalyst based on zinc, such as BiCat Z supplied Shepherd Chemical Company, or a catalyst based on bismuth, such as BiCat V Shepherd.

Especially the catalyst is recommended when using HDI.

After the application of MDI or a mixture of MDI and catalyst on the mobile mass of particles or granules of urea on the mobile mass of particles or granules is applied a second coating comprising a mixture of an alkyd resin having double bonds, oil, it is l or solvent. The preferred oils are dehydrated castor oil and Tung oil. Alkyd resin is a compound containing, along with the double bonds of hydroxyl and carbonyl groups. The hydroxyl group can interact with the isocyanate group with the formation of the polyurethane, and the double bond may be in free radical polymerization with the oil and the resin.

Double bonds appear in each repeating part and can be in the skeleton or the side chain.

The chemical structure of alkyd resins is:

where n represents the degree of polymerization,

G is a monoglyceride having the structure

RA is polonovski acid, having the structure of noos----COOH

FA is a tall oil having the structure HOOCR' and including

46% of oleic noos(CH2)8CH=CH(CH2)6CH3

46% linoleic, noos(CH2)7CH=CHCH2CH=CH(CH2)4CH3

13% other fatty acids.

Covering a mixture of alkyd resin, oil, initiator, catalyst and, optionally, promoter and/or duly in the first stage or phase of the coating interacts with-IT, and-COOH in the alkyd resin and-COOH in oil in accordance with the polymerization by condensation:

R-NCO+HO-R'R-NHCOO-R'

R-NCO+NOAS-R''-[RNHCOOOC-R'']- R-NHCO-R''+CO2

Free radical polymerization of alkyd resins and oils occurs simultaneously with the polymerization by condensation of excess isocyanate, alkyd resins and oils.

The double bond in the alkyd resin may also interact with the double bonds in the oil, simultaneously forming as a result, the coating on the particles in the form of vzaimopronikayut polymer network, in which all component parts, including oil, are chemically bonded with each other and with particles.

Types of free radical polymerization of alkyd resins and oils can be expressed as follows:

where R', R", R"' represent alkyl chain. R-CH=CH-R' R"-CH=CH-CH=CH-R"' may also interact with each other, forming a cross-linked polymer. This reaction gives the opportunity to form a three-dimensional stitching between the alkyd resin and oil, which in turn stimulates the formation of shells from three-dimensional vzaimopronikayut polymer network with a high density of cross-linkage on each of the particles or granules of urea.

One of alkyd resins, preferred in izobretateley 8-30, BUT the value in mg KOH/g solids is 155-160 and a viscosity at 23° C is 2500-3500 MP (2,5-3,5 g/(cm· s)). Other alkyd resins, preferred in the invention to practice, is 7482 lubomirskia alkyd resin supplied Ohio PolyChem, which contains 10% PMA and has an acid number of 19 and a viscosity of V-X. To make the coating improved physical properties such as tensile strength of the film tension can be applied alkyd resin having a higher viscosity, for example 3500-9000 MP (3,5-9.0 g/m· s)) at 23° C. One example is DynotalT T-49-EMP viscosity 6000-9000 MP (6,0-9,0 g/m· s)) at 23° C. However, the use of resins of very high viscosity will typically require initial roofing granules of urea wax and application of a diluent or solvent to reduce the viscosity during application covering the mixture into granules.

Suitable for use can be oils, other than Tung oil and dehydrated castor oil having double bonds, interacting with double bonds in the alkyd resin, for example linseed oil, sunflower oil, tall oil and the oil of safflower. However, dehydrated castor oil and Tung oil predpochitaemaya its long-chain carbon skeleton they attach to the floor flexibility.

The initiator is used in a mixture of alkyd resin/oil for the initiation of free-radical polymerization mixture. Although it is not emphasized above, the catalyst and/or polymerization promoter are optional and preferred components of the mixture covering serving to increase the reaction rate and minimize the curing time of the coating. The initiator may be selected from a ketone peroxides, such as ethyl ketone peroxide, benzoyl peroxide and Gidropress cumene. Preferred currently initiator available under the trademark DDM elf autochem. The promoter may be a metal or compound of a metal, such as cobalt or vanadium. Can be also applied this catalyst, such as tin, zinc, iron, lithium, bismuth, compound of potassium and amine. Suitable catalysts based on tin are T1 and T12 from Air Products. A suitable compound of zinc is a BiCat Z from the Shepherd. A suitable catalyst based on bismuth is BiCat V from the Shepherd. A suitable catalyst based on amine is triethylenediamine, such as Amicure 33-LV from Air Products. In formulas where used HDI should be used one of the above catalysts.

In Zili solvent. For example, if the mixture of the second stage is applied hot, for example, at temperatures up to approximately, but not more than 50° C (122° F), the viscosity can be controlled only through the regulation of the temperature of application. If the mixture of the second stage is not heated or is not significantly heated, or the viscosity cannot be reduced one by heating, the mixture may be added a solvent selected from glycol ethers, such as methyl acetate ester of propylene glycol (PM acetate), ketones such as methyl ethyl ketone (MEK), and aromatic hydrocarbons, in an amount sufficient to reduce the viscosity to the desired consistency for application to mobile mass of granules or particles.

After the second stage covering the mixture hardens, may not necessarily be applied to the third stage of the coating, if necessary to meet the demands of prolonged release feeding or to comply with other physical or aesthetic criteria. The third stage covers the wax, preferably paraffin wax having a high degree of linearity and crystallinity and melting temperature 52-83° C (126-181° F). One example is paraffin wax, supplied by Lawter International, Inc. Kenosha, Wisconsin. polymer network, to achieve the purpose of controlling the speed of release of the feeding of the coated particles and granules with dressing.

The above reactions graduate education is not soluble in water vzaimopronikayut polymer network on the surface of the particle feeding or, perhaps more accurately, the transformation of the outer portion of the particles in the coating, including vzaimopronikayut polymer network, which is not soluble in water, saliva and gastric juices, but which decomposes to a degree sufficient to release the feed additive, i.e., to ensure leaching feed additives through the floor, for some period of time.

In one form of the invention, the urea or bearing urea granules or particles are loaded into the apparatus for coating and dried for from about 10 to about 40 minutes at 60 to 100° C (140-212° F). Mobile mass of particles then put the liquid isocyanate or a mixture of the isocyanate with the catalyst or diluent or with both of them in excess of from about 5 to about 10 times, preferably 6-8 times the amount needed for the reaction between isocyanate and urea, and incubated for a period of the NAT/urea. Then put the liquid particles or fluid mixture of alkyd resin, oil, initiator, catalyst and, optionally, promoter and/or solvent. To speed up reactions and reduce the curing time of the particles and the components of the coating is preferably heated before and/or elevated temperature is maintained at the level of the order of approximately 40-100° C, preferably approximately between 45 and 75° C. At these temperatures and with the right proportions of initiator and catalyst, the curing time is about 5 to 10 minutes.

The ratio of components applied to particles of feed additives for the formation of a coating of vzaimopronikayut polymer network, are preferably of the order of from about 15% to about 45% by weight of isocyanate, from about 20% to about 60% by weight of an alkyd resin, from about 5% to about 35% by weight of oil and from about 0.05% to about 10% by weight of initiator and promoter. If necessary, you can use the solvent in a ratio to approximately 40%.

More preferred ranges of the components are approximately 20-40% by weight of isocyanate, 25-60% by weight of an alkyd resin, 5-25% by weight oil, 0,0 is SyteLine 7:5 to about 9:1. For resins with low viscosity, for example Dynotal T-39-EMP, preferred ranges of the components constitute 20-40% by weight of isocyanate, 30-55% by weight of an alkyd resin, 5-20% by weight oil, initiator and solvent.

The ingredients that form a polymer network, can be applied to nutrient particles in amounts, expressed in weight of the coating constituting from about 2% to about 5%, more preferably from 3% to 4% and most preferably about 3% by weight from the treated particles of urea. Coating weight based on dry polymer mesh. The solvent, initiator, catalyst and wax are not included. Coating weight of 3% means that 100 parts of urea have three part polymer coating. After curing the polymer mesh particles preferably cover an additional shell of paraffin wax in an amount of from approximately 0.5% to approximately 2.0%, preferably about 1% by weight of particles feeding.

The application of the granules of urea coating consisting of about 3% by weight of the coating of vzaimopronikayut polymer mesh and 1% by weight of paraffin wax, gives nutrient nitrogen product having essentially postoyannuyu scars (cows) during the period of 24 hours.

The rate of release of nitrogen in the soil was determined experimentally in accordance with accepted laboratory technique, when 10 grams of the coated urea immersed in 100 cm3cold water for a certain number of days (in this case 30 days) and record the speed and nature of the release using standard procedures of analysis. Based on comparative tests, one day in the water approximately equivalent to one week in the soil.

The rate of release of NPN scars was determined by extraction of the compared samples of scars dairy cows with fistula treated diets, respectively including and not including coated urea, and using the periodic sampling jugular blood from the same cows. Tests have allowed to establish that coated urea according to the invention, even when fed in much larger quantities than what would be normal, i.e., up to 10 times the number compared to the norm, was completely non-toxic to animals. Comparative tests hereinafter allowed to establish increased bacterial activity in the rumen, a significant increase in the production of milk fat and oils from Molok is>P CLASS="ptx2">Previously the maximum daily dose of urea, which can be safely fed to cows, was one-eighth pounds (56.7 g); one sixteenth of a pound (28,3 g) twice a day. Now a day the dose can safely and easily increase four times to POLUTANT (227 g) per day without toxic effects. Given that urea when the expression on the pound gives five times more NPN compared to soybean flour, a simple doubling of urea in the diet up to one-quarter pound (113 g) per day should be reduced by one and a quarter pounds (567 g) the amount of soybean flour required in the diet. Price 1998-1999 this would lower the cost of food (depending on geographical location) from about 10 to about 30 cents a day per cow. If the content of urea was increased to POLUTANT (227 g) per day, the savings would be double. Furthermore, cows that fed coated urea, produce more milk, which has (b) higher fat oil and, therefore, more valuable goods compared with milk from cows that are not fed coated urea. For the dairy industry there are significant economic consequences.

In particular, when the s / day) coated urea according to the invention with controlled release and two and a half pounds (1,133 kg) soy flour, given the growth of milk production on eight pounds per day, and received the milk contained 10-20% more fat oil and significantly improved the protein content. Also, apparently, has decreased the number of animal excrement.

Typical examples of components expressed in weight percent, of the polymer coating with polymeric MDI and alkyd resins with low viscosity, for example Dynotal T-39-EMP presented in table 1.

In the case of polymer networks using alkyd resin with high viscosity, for example, viscosity 6000-9000 MP (6-9 g/(cm· s)) at 23° C, preferably before applying the isocyanate particles of urea applied soil coating of paraffin wax. At processing temperatures from about 50° C to about 100° With wax, apparently, acts as a lubricant or solvent for alkyd resins with higher viscosity and promotes uniform distribution of resin on top of the particles. Similarly, the viscosity of the resin is preferably reduced by addition of a mixture of alkyd resin/oil from about 12 to about 22 wt.% with respect to acetate, preferably the RM acetate.

System for coating particles of urea alkyd resin with wysokiego polymer coating and 1% by weight of the outer coating of wax.

Typical examples of components of the polymer coating with polymeric MDI and alkyd resin with high viscosity, for example Dynotal T-49-EMP, expressed in weight percent shown in table 2.

A typical example of a composition for coating with polymeric HDI and alkyd resins with low viscosity at the expression in the weight percentages given in table 3.

Polymeric HDI, the catalyst T12 and the solvent RM acetate form the first mixture coating for the coating of granules of urea. HDI can be any of the N3300, N75BA and HR company Voeg. In the above preferred composition N3300. In HDI N3300 the NCO content is from 21.3 to 21.8%, a viscosity of 1800-4000 MP (1.4 to 4 g/(cm· s)) at 25° C and a functionality of about 3.5.

The solvent RM acetate is recommended for use with N3300, but the demand for it may not be with HDIs lower viscosity, such as N75BA and HR.

In HDIN75BA the NCO content is 16.2-16.8 percent, viscosity 90-210 MP (0,09-210 g/(cm· s) ) at 25° C and a functionality of about 3. Functionality HDI HR is 3, the NCO content of 20-21% and a viscosity of 800-1200 MP (0,8-1,2 g/ (cm· s)) at 25° C.

Alkyd resin, oil, initiator DDM, peroxide Bense the isocyanate. The preferred resin is a T-39-EMP with low viscosity. For dehydrated castor oils require higher processing temperatures than Tung oil as dehydrated castor oil contains two conjugated double bonds, and Tung oil to three conjugated double bonds. Tung oil reacts faster than castor oil and at lower temperatures, and, therefore, it is usually preferable to castor oil. Free radical coinitiator - benzoyl peroxide is an optional but preferred component of the composition.

After coating a polymer resin usually add wax as the final coating layer.

In table 3 refers to the index of the BRICs, is equal to zero. Figure Brix serves as an indicator of release into the water coated urea determined with a Refractometer. The Refractometer reading or indicator Brix can be transformed in the refractive index, which is one of the most important properties of an aqueous solution of urea. Figure Brix can also be transformed in the concentration of the solution. The test is usually conducted by mixing 15 grammage up to two months, depending on the speed of release. The indicator of the BRICs as a function of the concentration gives a calibration curve, which is easy to calculate the percentage of release of urea in the liquid:

Y (release %)=(a+b)X/A,

where a represents the weight of sample (g),

In represents the amount of water (ml)

X is a measure of the BRICs, and

Y is % release.

During the test Brix using a Refractometer to measure the percentage of solids in the solution. When dissolved in water a certain amount of urea, the rate of BRICs solution reflects the concentration of urea. Thus, it is simple, fast and accurate method of determining the quality of coated urea. The method can be combined with the method, based on the weight reduction to produce results based on both solid and liquid phases.

In the structure presented above in table 3, the need for solvent RM acetate could be reduced or eliminated, and the viscosity of the mixture covering modified through the use of two or more polymer HDIs with different viscosity, for example, by mutual mixing of two or all three N3300, HR and N75BA to obtain viscosity, premiati 3,0, and N3300, part of 3.5. Higher functionality provides greater density of cross-linkage, which increases resistance to water.

To obtain high-performance coating for urea can also be used Monomeric HDI with polymeric HDI. For example, Desmodur monomer HDI Bayer's (M-HDI), added to polymeric HDI (P-HDI) N75BA, HR and/or N3300 at a concentration of 10% by weight or more network covering the mixture with a significantly reduced viscosity and high yield; thus, the viscosity Bayer's Desmodur H is only 3 MP(0.003 g/ (cm· s)), the NCO content is 49%,which, therefore, provides a reduction in the part number P-HDI, which is the most expensive component.

Table 4 presents examples of coating compositions comprising P-HDI and the monomer or M-HDI.

Test results release urea for formulations with different ratios of M-HDI and P-HDI XP7100 and P-HDI N75BA presented in table 5.

40% P-HDI N75BA with 60% M-HDI showed the best results for all investigated compositions. For P-HDI HR the best results were obtained with 60% P-HDI and 40% M-HDI. The results show that the monomer promotes wetting and coating pave monomer.

When HDI is used for the first coating or primer, the conditions differ from those used with MDI, in particular, this applies to the cooling-off period after priming. Time priming HDI was determined in 30 minutes for approximately 15 grams of liquid and were used to define the exposure time in 2.5 and 12 minutes. It was found that if the exposure time is more than about 5 minutes, then HDI starts to react with urea or with himself, urea becomes sticky,and the output of urea difficult. Investigated also the time of applying the second coating, it was found that the best was the time in 5 minutes.

In addition to mixtures of HDIs with different viscosity and mixtures M-HDI with P-HDI in the invention offers additional coverage and benefits due to impurities MDI and HDI. Two isocyanate with different molecular structure can be mixed and applied to the urea for the formation of cross-linked coating. Currently, the market value of MDI is typically three times lower than the cost of HDI, and replacement parts on HDI MDI provides a more economical product. Typical composition shown in table 6.

Tests of the release into water of urea, n is evina begins to stand out. To 50 hours indicator Brix was 0.2, indicating that the release of 1% urea in water. On the 18th day indicator Brix was equal to 7.4, which indicates the release of 32% urea in water. Thus, the composition produces a product of urea coated with a polymer mesh, with perfectly controlled release characteristics.

In each of the above compositions a polymeric mesh must be in the correct ratio between particles, isocyanate, alkyd resin and oil to reduce the presence of unreacted components in the final product. If the content of the isocyanate in the composition is too low, alkyd resin and oil will not be able to react. If the content of the isocyanate in the composition is too high, it will remain unreacted excess isocyanate. Unreacted chemicals can act as contamination of the coating, in particular unreacted hydrophilic groups will attract moisture and accelerate the release of urea, which, of course, should be avoided or that, at least, should be kept to a minimum.

Typical proportions of the components of the coating compositions for urea by weight, in parts, in pounds, grams, or pounds is hetenyi methods or processes for coating or treatment of urea is fully compatible with traditional commercial and industrial practice. Urea in the form of particles or granules may have two covers mix, applied sequentially in a single pallet to cover or mixer, or in two adjacent pallets to cover or mixers, and the coated granules may be cool at the same or another pallet or similar device capable of providing a surface finishing process of coated pellets before drying. The process may be continuous or periodic.

In one example, granules of urea is first dried to remove moisture. Urea is then put in a "Rollo Mixer" manufactured by Continental Products Corporation, Milwaukee, WI, followed by passing through a heating drum and the cooling drum. In the mixer urea rises along the front side of the mixer and falls freely inside the mixer in the drop-down flow. This continuous free-falling curtain exposes the surface of individual granules in the dough. Then on both sides of the veil razbrasivayutsya chemicals, and after additional mixing in the lower part of the mixer chemicals are evenly distributed over the surface of the granules. The first component of the atomizer, which mainly diisocyanate, called a primer. It reacts with urea from obrazini final dry coating. Then add the second component of the spray, including alkyd resin, oil, free radical initiator and a catalyst. Immediately after spraying the second component, the temperature was raised to 48-71° C (120-160° F) depending on the oil. After the second component was spattered coated granules are transferred to a heating drum for curing. During the curing of alkyd resin reacts with excess isocyanate groups from the first spray with the formation of urethane bridge. At the same time under the action of the initiator free radicals must start the polymerization of the double bonds as in alkyd resin and oil. The resulting reaction is both free-radical polymerization condensation. The temperature of curing is maintained at the level 43-71° C. Cooling the coated urea can be produced in a different drum, where the temperature is maintained at level 38° C (100° F).

Treatment of urea or the coating process of the present invention is also fully compatible with traditional methods of production of urea and can be advantageously added in the form of a relatively simple attachment to the traditional line is Auda rather uniform in shape and size, have a relatively small surface and discharged at a temperature suitable for carrying out the invention for the rapid conduction of polymerization reactions and to minimize the curing time.

In one of the specified commercial practice methods for the production of urea add a device for coating the drum-type or a continuous mixer of the type of action in the traditional version for acceptance from the line of hot particles. If necessary or if desired, can be added a suitable pumping system and the air system. The rotating drum provides a continuous flow of the mobile mass of the rotating halloysite falling down the stairs or freely falling particles. In the drum are mounted two or more spray devices for the coating of particles in the moving mass of particles of liquid isocyanate and a fluid mixture of alkyd resin, oil, initiator and, optionally, promoter and/or solvent. If desired, prior devices for the application of the isocyanate and/or main part, of oil and of the initiator, you can put a device for applying wax by spraying. The speed of the application by spraying of the coating components to the mass of particles correlates with emich ratios and quantities for education on them cover from vzaimopronikayut polymer network with a given weight and, optionally, a suitable wax primary and/or surface coatings. The process is continuous and is carried out in an efficient and fast.

Thus, as shown, achieved objectives and advantages of the invention in terms of convenience, practicality, efficiency and ease.

Although there have been described certain preferred embodiments of the invention, it should be understood that it can be made various changes, rearrangements and modifications without going beyond the scope of invention, as described in the claims.

1. Product controlled release comprising particles or granules consisting entirely or mainly of urea or containing urea at its outer surface or on them, and water resistant coating on the particles of vzaimopronikayut polymer network consisting of a reaction product of urea and isocyanate interacting with urea, and the reaction products of an excess of isocyanate over it, and reacted with urea, alkyd resins and oils containing at least one double bond.

2. The product under item 1, where the isocyanate is a polymeric ptx2">3. The product p. 1 wherein the alkyd resin comprises a compound containing hydroxyl and carbonyl groups and double bonds, and hydroxyl group capable of reacting with the isocyanate to form polyurethane and double bonds capable of free-radical polymerization with each other and with oil.

4. The product under item 1, where the oil is dehydrated castor oil or Tung oil.

5. The product under item 1, where the coating of vzaimopronikayut polymer network comprises the products of interaction of components comprising from about 15 to 45% of the isocyanate, approximately 20-60% of an alkyd resin and from about 5 to 35% oil.

6. The product under item 1, where the coating of vzaimopronikayut polymer network comprises the products of interaction components between approximately 20 to 40% of the isocyanate from 25 to 60% alkyd resin and from 5 to 25% oil.

7. The product under item 1, where the coating of vzaimopronikayut polymer network comprises the products of interaction components between approximately 20 to 40% of a polyfunctional isocyanate, from about 30 to 55% of an alkyd resin with a viscosity of not higher than 3500 MP (3.5 g/(cm·C)) and from about 5 to 20% oil.

8. Provde the outer coating of wax ranges from approximately 0.5 to approximately 2.0% by weight of the coated particles.

10. The product under item 5, where the alkyd resin has a viscosity of from about 6000 MP (6 g/(cm·C)) and above, and the particles have a coating of wax under the coating of the polymer network and a coating of wax over the floor of the polymer network.

11. The product under item 1, where the coating of vzaimopronikayut polymer mesh is from about 2 to about 5% by weight of the coated particles.

12. Product urea-based controlled release comprising particles or granules consisting entirely or mainly of urea or containing urea at its outer surface or on them, and water resistant coating on the particles of vzaimopronikayut polymer network consisting of a reaction product of urea and a polyfunctional isocyanate, interacting with urea, and the reaction products of an excess of isocyanate over it, and reacted with urea, alkyd resin containing at least one double bond in each repeating part, and oils containing at least one double bond, cover, comprising from about 2 to about 4% by weight of the coated particles and consisting of from about 20 to about 40% by weight from the 20% oil by weight.

13. The product p. 12, including the outer coating of wax on the coated particles.

14. The method of processing particles consisting entirely or mainly of urea or containing urea at its outer surface or on them, the result of which is controlled by the rate of release of urea, including the stage of creation of the mobile mass of particles, heat and/or heat storage of the mobile mass of particles deposition on heated mobile mass of particles reacting with urea isocyanate in excess required for the reaction with urea on the surface of the particles, applying to the treated isocyanate mobile mass of particles of a mixture of an alkyd resin containing at least one double bond in each repeating unit, and oil, containing at least one double bond, and an initiator for initiating free-radical polymerization mixture and continue maintaining the treated particles in a heated movable mass in a period of time sufficient to complete reaction of the isocyanate with urea, reaction of the isocyanate resin and oil and polymerization of the resin and oil, and these stages are effective in the transformation of the surface treated particles in p for a controlled period of time.

15. The method according to p. 14, including the stage of applying wax on the mobile mass of the particles before and/or after application of the isocyanate, alkyd resins and oils.

16. The method according to p. 14, including the stage of applying isocyanate, alkyd resins and oil particles in amounts from about 2 to about 5% by weight of the coated particles.

17. The method according to p. 14, including the stage of applying isocyanate, alkyd resins and oil particles in the respective proportions: approximately 15 to 45% of the isocyanate, from about 20 to about 60% alkyd resin and from about 5 to about 35% oil.

18. The way the plants, including the stage of making of the product p. 1 soil in which to grow these plants.

19. The method of feeding ruminants, including the stage of making of the product under item 1 in the feeding ration some animal.

20. The method according to p. 19, where the product under item 1 included in the diet in the amount of 1/4 pound (113 g) or more per day.



 

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