GB2174689A

GB2174689A - Highly concentrated fertilizer for spraying on leaf surfaces and its manufacture

Info

Publication number: GB2174689A
Application number: GB08511846A
Authority: GB
Inventors: Takashi Tozawa; Masahiro Endo; Ichiro Maejima; Keiko Morishima
Original assignee: Mitsubishi Chemical Industries Ltd
Current assignee: Mitsubishi Chemical Corp
Priority date: 1985-05-10
Filing date: 1985-05-10
Publication date: 1986-11-12
Also published as: GB8511846D0

Abstract

A highly concentrated fertilizer is provided which is useful for spraying upon leaf surfaces and contains 100 pts. wt. of urea, 0.1 to 500 pts. wt. of a sucrose fatty acid ester prepared by using either a saturated fatty acid containing 10 to 18 carbons or an unsaturated fatty acid containing 18 carbons and 100 to 500 pts. wt. of either monobasic potassium phosphate alone or a combination of monobasic potassium phosphate and dibasic potassium phosphate. The pH of an aqueous solution of the fertilizer is 4 to 7.5. There is also provided a method of preparing a fertilizer in which urea and said sucrose fatty acid ester are dissolved in water containing ethylene-diamine-tetraacetate.

Description

SPECIFICATION Highly concentrated fertilizer for spraying on leaf surfaces and its manufacture This invention relates to a highly concentrated fertilizer containing a sucrose fatty acid ester and urea for spraying upon leaf surfaces and its manufacture. This invention, more particularly, relates to a highly concentrated fertilizer and a method for producing the same, the highly concentrated fertilizer being properly diluted into a liquid fertilizer which is applied for sprinkling over leaf surfaces of plants or which is pressurized and charged together with a spray agent in a spray container to obtain a fertilizer for spraying over leaf surfaces.

Fertilizers for sprinkling over leaf surfaces containing urea and a sucrose fatty acid ester are described in Japanese Patent Disclosures Nos 56-78484, 56-78485 and 57-95885. These fertilizers are all either powders or creams and diluted with water into a proper concentration before being practically used for sprinkling. However, since a fatty acid ester of sucrose is basically difficult to dissolve in water, a dilute aqueous solution for practical use can not be easily prepared from the powder or cream without consuming time and energy.Especially, for indoor gardening and small-scale cultivation such as home gardening, adjustment of the concentration is troublesome. N In order to produce a highly concentrated liquid fertilizer containing urea and a sucrose fatty acid ester which can be easily diluted into a solution for sprinkling over leaf surfaces of plants or into a proper concentration for spraying over leaf surfaces in its production by pressurizing and charging the properly diluted solution and a spray agent into a spray-case and which then can be conveniently stored and transported, the inventors studied the solubility of each component of the fertilizer, the method of preparation of a liquid fertilizer and related topics.As the result, the following facts were discovered. (1) A relatively stable high concentrated aqueous solution can be prepared by adding a specified concentration of a phosphate to urea and a sucrose fatty acid ester. (2) Especially, in a fertilizer containing a sucrose fatty acid ester and a specially high concentration of urea and optionally containing a phosphate, a highly concentrated liquid fertilizer which can be diluted without producing any insoluble matters is produced by using an ethylenediamine-tetraacetate and dissolving all these components in a controlled sequence. (3) Additionally, the spray fertilizer prepared by pressurizing and charging a spray agent and a dilute aqueous solution prepared from the above highly concentrated liquid fertilizer into a spray-case can also be directly sprinkled over leaf surfaces and has excellent preservation performance and fertilizing effect.

It is an object of the invention to produce a highly concentrated fertilizer containing urea, a sucrose fatty acid ester and a phosphate.

It is another object of the invention to develop an effective method of manufacturing a highly concentrated liquid fertilizer containing urea, a sucrose fatty acid ester and a phosphate.

It is further object of the invention to produce a fertilizer for spraying over leaf surfaces by pressurizing and charging a spray agent and a dilute aqueous solution prepared from the above highly concentrated fertilizer containing urea, a sucrose fatty acid ester and a phosphate in a spray container.

This invention will be described in detail. In the present fertilizer according to this invention, urea is blended as an essential component and is appropriately selected from the usually used powders and grains. Urea which is easily absorbed by plants serves as a metabolic source of nitrogen thereby promoting growth. In addition, it is estimated that the absorption of urea is accelerated and its fertilizing effect is increased by a sucrose fatty acid ester to be described later. However, it was very difficult to dissolve urea in a concentration of over 40 wt% in the presence of a sucrose fatty acid ester. Especially, in the coexistance of both a phosphate and a sucrose fatty acid ester, it was difficult to dissolve urea in a concentration of not lower than 25 wt%.However, a urea solution of such a specially high concentration can be prepared, according to the method of this invention, by dissolving an ethylene-diamine-tetraacetate in water prior to dissolving urea and a phosphate.

It is necessary that the sucrose fatty acid ester used for this invention is soluble in water. In order to realize such solubility, the fatty acid moiety of the sucrose fatty acid ester should be either a saturated fatty acid containing 10~18 carbons or an unsaturated fatty acid containing 18 carbons. Capric acid, lauric acid, myristic acid, palmitic acid, stearic acid and oleic acid can be used as such fatty acids. The ester used for this invention is either one of a mono-, di-, triand other esters or one of their mixture prepared by causing sucrose to react with either one of these fatty acids or one of their mixtures. These sucrose fatty acid esters have an HLB of not lower than 9, preferably not lower than 11.The ratio of the sucrose fatty acid ester to urea is 0.1~500 pts. wt., preferably 0.5~100 pts. wt. to 100 pts. wt. In the case that the sucrose fatty acid esters have the fatty acid moiety of not less than 20 carbons and that they have an HLB of lower than 9 even though their fatty acid moiety contain 10~18 carbons, they are not stably soluble in a diluted spray solution thereby causing a problem in its storage as solution.

When the ratio of the fatty acid ester to urea in the highly concentrated fertilizer is smaller than 0.1 pts. wt. to 100 pts. wt., the sucrose fatty acid ester does not exhibit its effect of accelerating absorption of the nutrition. in contrast, when this ratio exceeds 500 pts. wt. to 100 pts. wt., a dilute spray solution prepared from the highly concentrated fertilizer can not be handled easily because of its high viscosity and is not suitable used for spraying.

In preparing the highly concentrated liquid fertilizer according to this invention, it is preferable for rapid preparation of the solution to dissolve the sucrose fatty acid ester at the first, if possible, because of its low solubility although there is no special restriction to the order. A potassium phosphate is added not only as a fertilizing component but also has the effect of controlling the pH level of aqueous fertilizer solutions thereby maintaining a safe pH balance for plants and inhibiting corrosion of the case during storage. Monobasic phosphates and dibasic potassium phosphates can be used as phosphates. In both of the cases when monobasic potassium phosphate is used alone and when monobasic potassium phosphate and dibasic potassium phosphate are used in combination, a total of 10~500 pts. wt. of the phosphates is used for 100 pts. wt. of urea.When the amount of the potassium phosphates used is smaller than 10 pts. wt. for 100 pts. wt. of urea, since the amounts of phosphorus and potassium are smaller as compared with the amount of nitrogen supplied from urea contained in the solution, a sufficient fertilizing effect can not be expected after the solution is actually used for spraying. In contrast, an amount exceeding 500 pts. wt. of the potassium phosphates is not favorable because it arises a possibility that plants may be damaged due to an excessive concentration of the salts.

The fertilizer according to this invention is prepared so that its aqueous solution maintains its pH level at 4~7.5, preferably 6.5~7.5. When monobasic potassium phosphate and dibasic potassium phosphate are used simultaneously, the above pH level can be controlled by changing the proportion of dibasic potassium phosphate. As long as no such substances that may influence the pH level are employed, it is preferable that the ratio of KH2PO4 to K2HPO4 be about 2:3. When the aqueous solution of the fertilizer is stored in a metallic case such as a tin plate case, it is recommended that the pH of the solution be not less than 6 in order to avoid the corrosion of the case. ApH of the solution less than 4 or greater than 7.5 is not favorable because sprinkling of the solution upon plants will have an adverse effect.

The high concentration fertilizer of this invention is manufactured by mixing together urea, the sucrose fatty acid ester and the potassium phosphate by an arbitrary method. It can be usually manufactured by homogeneously mixing powder or granules of urea with powders of the sucrose fatty acid ester and the potassium phosphate using a proper mixer. The thus manufactured highly concentrated fertilizer powder can be converted into a liquid or paste if necessary by adding 10~1,000 pts. wt. of water for 100 pts. wt. of urea. A complete aqueous solution can be obtained by adding not smaller than 100 pts. wt. of water and by properly selecting the proportion of each component. This dilution method is preferable since it facilitates subsequent dilution and pressure charging according to the following procedure.Here, since a too large amount of water decreases the concentration of each component resulting in an increased transportation cost of this fertilizer, it is recommended that the amount of water added be as small as possible. The amount of water added is usually not smaller than 100 pts. wt., preferably in the range of 100~200 pts. wt.

In a system containing urea, the phosphate and the sucrose fatty acid ester, not oniy the solubility of urea was influenced as mentioned above but also it was difficult to dissolve the phosphate homogeneously in a concentration of 10 wt% or greater. However, with this invention, the phosphate can be homogeneously dissolved in high concentration by dissolving an ethylene-diamine-tetraacetate prior to dissolving urea, followed by dissolving the phosphate added if necessary.

For ethylene-diamine-tetraacetate, various salts such as sodium, potassium, iron and ammonium salts of ethylene-diamine-tetraacetic acid can be used among which the iron salt is preferred.

In the highly concentrated liquid fertilizer of this invention, it is necessary that the concentration of the ethylene-diamine-tetraacetate be not lower than 0.1 wt%. When the concentration of the ethylene-diamine-tetraacete is below 0.1 wt%, urea or the phosphate can not sufficiently be dissolved and the purpose of this invention can not be attained. Accordingly a concentration of not smaller than 0.1 wt%, preferably 1 20 wt% is usually employed.

In the manufacturing liquid fertilizer of an especially high concentration according to this invention, it is preferable that the ethylene-diamine-tetraacetate be dissolved before dissolving urea and the phosphate. Usually, after the sucrose fatty acid ester is dissolved in water at room temperature to make an aqueous solution, the ethylene-diamine-tetraacetate is dissolved, then urea and the phosphate if necessary are dissolved in that order. It is difficult to prepare a highly concentrated fertilizer solution in another order without producing residual undissolved matter.

A highly concentrated liquid fertilizer prepared by the method of this invention is a homogeneous liquid despite its high concentration, and a dilute aqueous solution for practical use prepared from the highly concentrated fertilizer maintains the quality level of the original concen trate. In addition, it can be very easily handled during transportation, subdivision and dilution after the preparation. Thus it has an excellent economical value.

The highly concentrated liquid fertilizer can be combined with other plant nutrients such as trace elements including boron and manganese, agricultural agents, aromatizers and the like.

Since excessive quantities of these members will deteriorate the stability of the fertilizer solution and may lead to easy formation of precipitates, it is necessary that these members should be added after their stabilities have been investigated.

The highly concentrated fertilizer for spraying upon leaf surfaces according to this invention is usually diluted with water into a given concentration to obtain nutrient concentrations favorable for practical use The dilution is performed so that the concentration of urea, the sucrose fatty acid ester and the potassium phosphate become 0.02~2 wt%, 0.001 1.0 wt% and 0.0021.0 wt% respectively. Here, since an excessively high concentration of salts will cause salt injuries to leaf surfaces, it is preferable that the electric conductivity of the dilute solution should be 7 mS/cm or below, preferably 5 mS/cm or below.

The thus obtained dilute solution and a spray agent (such as LPG or dimethylether used for usual aerosol propellant) are pressurized and charged in a case such as a tin plate or aluminum can having a function as a spray container to obtain a fertilizer for spraying over leaf surfaces of various plants irrespective of whether they are grown outdoors or indoors, and is preferable that it is used in home gardening especially for those foliage plants such as gum trees, photos and begonias which are grown in the room. It is recommended that the amount of the fertilizer applied each time is adjusted so that the entire surface of the leaf is moistened without causing any droplets. It is preferred that the fertilizer is applied once per 2~3 days to one week.

The thus obtained fertilizer for spraying over leaf surfaces containing nitrogen, phosphorus and potassium as its main ingredients, when being used for plants, will make leaves take on a fresh green color and improve their luster thereby improving their appearance. It will also enhance the growth of plants. Additionally, the sucrose fatty acid ester will accelerated absorption of each nutrient into leaf surfaces thereby accelerating the fertilizing effect.

This invention will be described in more detail according to the following examples. This invention is not restricted to the following examples as long as its essential point is not altered.

Example 1 Three g of sucrose fatty acid ester (trade mark, Ryoto Sugar Ester L-1540; manufactured by Mitsubishi Chemical Industries Ltd.; having an HLB of 15 and prepared using lauric acid accounting for 50% of all fatty acids used) and 4 g ethylene-diamine-tetraacetic acid iron salt (C10H,2N20 8NaFe.3H20) were dissolved in 55 g of distilled water. Following that, 47 g of urea was added while stirring to completely dissolve it, thereby obtaining a transparent homogeneous solution.

After being left at room temperature for one week, this solution maintained its stability without causing any precipitates.

Comparative Example 1 After 3 g of the sucrose fatty acid ester same as that used in Example 1 was dissolved in 55 g of distilled water, the solubility of urea in this solution was studied by adding small portions of urea successively. Dissolving over 40 g of urea (41 wt% of the total solution) was difficult and produced white precipitates. Here, a little over 40 g of urea was completely dissolved by heating (about 55"C), but precipitates were reproduced when the solution was cooled to room temperature.

Comparative Example 2 When 4 g of ethylene-diamine-tetraacetic acid iron salt was added after 40 g of urea was added in the same manner as the above comparative example 1, much more undissolved matter was observed.

Example 2 Three g of the same sucrose fatty acid ester as used in Example 1 and 4 g of ethylenediamine-tetraacetic acid iron salt were dissolved in 55 g of distilled water. Then, after 47 g of urea was dissolved in the solution, 25 of mixture consisting of monobasic potassium phosphate and dibasic potassium phosphate (in ratio of weight of 2:3) was added while stirring to completely dissolve the mixture, thereby obtaining a transparent homogeneous solution.

Comparative Example 3 After an aqueous solution of the sucrose fatty acid ester and ethylene-diamine-tetraacetic acid iron salt is prepared in the same manner as the foregoing Example 2, the solubility of the same potassium phosphate mixture as used in Example 2 was studied by adding small portions of the mixture successively. Dissolving over 15 g of the mixture was difficult and undissolved matter was observed.

Comparative Example 4 When 47 g of urea was added to an aqueous solution prepared in the same manner as the foregoing Comparative Example 3 and containing 15 g of the potassium phosphate mixture, much more undissolved matter was observed.

Example 3 Mixture containing 100 pts. wt. urea, 21 pts. wt. monobasic potassium phosphate and 32 pts. wt. dibasic potassium phosphate was combined with 7 pts. wt. of each of various kinds of sucrose fatty acid esters prepared by using different fatty acids listed in Table 1 to obtain highly concentrated fertilizers containing different sucrose fatty acid esters for spraying upon leaf surfaces. After each of these fertilizers was diluted 100 times to obtain a concentration for spraying upon leaf surfaces, the solubility of the dilute solutions were studied. The results are shown in Table 1. When soluble and easily soluble ones among these dilute solutions were left at room temperature for one week, they all maintained their stability without producing any precipitates.

Table 1

Sucrose Fatty Acid Esters Solubility Fatty Acids Used for Preparing Sucrose Fatty Acid Esters HLB Number of Number of Carbons Double Bonds Caprylic acid 8 0 5 - Capric acid 10 .. 16 ++ " | " | " | 5 | Lauric acid 12 " 16 ++ " " " 15 ++ " " " 5 Myristic acid 14 " 16 ++ " | " | " | 5 | Palmitic acid 16 " 16 + Stearic acid 18 " 15 + " | " | " | 3 | Oleic acid " 1 16 ++ 15 .. .. 15 ++ " | " | " | 5 | Arachidic acid 20 0 15 - Behenic acid 22 0 15 - Solubility ++ : Easily soluble + : Soluble - :Insoluble Example 4 Mixture containing 100 pts. wt. urea, 21 pts. wt. monobasic potassium phosphate and 32 pts. wt. dibasic potassium phosphate was combined with 0, 0.1, 1 and 10 pts. wt. of Ryoto Sugar Ester L-1540 (trade mark, manufactured by Mitsubishi Chemical Industries Ltd, a sucrose fatty acid ester having an HLB of 15, containing about 70% of monoesters and prepared by using lauric acid accounting for 50% of all fatty acids used) to prepare highly concentrated fertilizers containing different amounts of the sucrose fatty acid ester for spraying upon leaf surfaces.After each of these fertilizers was diluted 100 times by water, 150 g of the thus prepared dilute solution and 78 g of dimethylether used as a spray agent are charged in a tine plate can the inner surface of which is coated with an epoxy resin at a pressure of about 5 kg/cm2G to obtain a fertilizer for spraying over leaf surfaces.

The thus obtained spray fertilizer was applied over leaves of soy beans. Leaves collected immediately after and two hours after the application were washed with water, and nitrogen and phosphorus dissolved in the washing liquid were measured to calculate absorption rates for nitrogen and phosphorus during the two hour period of each of the above fertilizer used for spraying leaf surfaces.

Table 2

Quantity of Absorption Rate Absorption Rate Sucrose Fatty Acid for Nitrogen (%) for Phosphorus (%) Ester (pts. wt.) 0 29 1 49 0.1 31 55 1 1 60 59 10 68 57 Example 5 One hundred pts. wt. of urea, 7 pts, wt. of Ryoto Sugar Ester L-1540, 21 pts. wt. of monobasic potassium phosphate, 32 pts. wt. of dibasic potassium phosphate and 7 pts. wt. of ethylene-diamine-tetraacetic acid iron salt (Clf,Hl2NvOBNaFe 3H70) were completely dissolved in 106 pts. wt. of water to obtain a yellow transparent highly concentrated liquid fertilizer for spraying upon leaf surfaces.

Claims

1. A highly concentrated fertilizer useful for spraying upon leaf surfaces containing 100 pts.

wt. of urea, 0.1 to 500 pts. wt. of a sucrose fatty acid ester prepared by using either a saturated fatty acid containing 10 to 18 carbons or an unsaturated fatty acid containing 18 carbons and having an HLB of not less than 9 and 100 to 500 pts. wt. of either monobasic potassium phosphate alone or a combination of monobasic potassium phosphate and dibasic potassium phosphate, and the pH of the aqueous solution thereof being 4 to 7.5.

2. A fertilizer according to Claim 1 which is a liquid fertiliser.

3. A highly concentrated fertilizer useful for spraying upon leaf surfaces according to either of Claims 1 and 2, in which the sucrose fatty acid ester is prepared by using a fatty acid chosen from among capric acid, lauric acid, myristic acid and oleic acid.

4. A highly concentrated fertilizer useful for spraying over leaf surfaces according to any one of Claims 1 to 3, in which the sucrose fatty acid ester is sucrose lauric acid ester.

5. A highly concentrated fertilizer useful for spraying upon leaf surfaces according to either of Claims 1 or 2, in which the HLB of the sucrose fatty acid ester is not less than 11.

6. A highly concentrated fertilizer useful for spraying upon leaf surfaces according to any one of Claims 1 to 5 which contains 0.5 to 100 pts. wt. of the sucrose fatty acid ester.

7. A highly concentrated fertilizer useful for spraying upon leaf surfaces according to any one of Claims 1 to 6, in which the ratio by weight of monobasic potassium phosphate to dibasic potassium phosphate is about 2:3 (by weight).

8. A highly concentrated fertilizer useful for spraying upon leaf surfaces according to Claim 2 or any one of Claims 3 to 7 as dependent on Claim 2 which contains 100 to 200 pts. wt. of water.

9. A fertilizer for spraying over leaf surfaces which is prepared by diluting a highly concentrated fertilizer as set forth in any one of Claims 1 to 8 to prepare an aqueous solution of the composition given below and press-charging the aqueous solution in a pressure resistant case.

Urea 0.02 to 2 wt% Sucrose fatty acid ester 0.001 to 1.0 wt% Potassium phosphates 0.002 to 1.0 wt%

10. A method of manufacturing a highly concentrated liquid fertilizer containing a sucrose fatty acid ester prepared by using either a saturated fatty acid containing 10 to 18 carbons or an unsaturated fatty acid containing 18 carbons and having a HLB of not less than 9 and not less than 40 wt% (to the total weight of the solution) of urea, in which not less than 0.1 wt % (to the total weight of the solution) of an ethylene-diamine-tetraacetate is dissolved prior to dissolving the urea in water.

11. A method of manufacturing a highly concentrated liquid fertilizer containing a sucrose fatty acid ester prepared by using either a saturated fatty acid containing 10 to 18 carbons or an unsaturated fatty acid containing 18 carbons and having an HLB of not less than 9, not less than 25 wt% (to the total weight of the solution) of urea and 10 wt% (to the total weight of the soluion) of either monobasic potassium phosphate alone or a combination of monobasic potassium phosphate and dibasic potassium phosphate, in which not less than 0.1 wt% (to the total weight of the solution) of an ethylene-diamine-tetraacetate is dissolved prior to dissolving the urea and the phosphate in water.

12. A method of manufacturing a highly concentrated liquid fertilizer as set forth in Claim 11, in which the phosphate is dissolved following dissolving the urea.

13. A method of manufacturing a highly concentrated liquid fertilizer as set forth in Claims 10 to 12, in which the ethylene-diamine-tetraacetate is ethylene-diamine-tetraacetic acid iron salt.

14. A highly concentrated liquid fertilizer obtained according to the method of Claim 10 and containing not less that 40% (by weight) of urea.

15. A highly concentrated liquid fertilizer obtained according to the method of Claim 11 and containing not less than 25% (by weight) of urea and not less than 10 wt% of phosphates.

16. A highly concentrated fertilizer substantially as hereinbefore described with particular reference to the Examples.

17. A method of producing a fertilizer substantially as hereinbefore described with particular reference to the Examples.

18. A fertilizer when produced by a method according to any one of Claims 10 to 13 and 17.