Herbicidal composition and method for applying herbicide

Abstract

To provide a herbicidal composition that enables enhanced herbicidal effects through the use of materials having low environmental impact.SOLUTION: A soil treatment-type herbicide is used in combination with cellulose microfibers to provide a herbicidal composition. Preferably, the cellulose microfibers are chemically modified.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to a herbicide composition and a method for spraying a herbicide. More specifically, the present invention relates to a herbicide composition that inhibits the germination and growth of weeds, and an effective method for spraying such a herbicide.

Background Art

[0002] Herbicides can be roughly classified into two types: soil treatment herbicides that are sprayed on the soil surface to suppress the germination of weeds or kill them immediately after germination, and foliage treatment herbicides that are sprayed directly on the leaves and stems of growing weeds to kill the weeds. Examples of soil treatment herbicides and foliage treatment herbicides are described in Patent Document 1 and Patent Document 2.

[0003] Since herbicides using chemicals are considered to have some toxicity to humans and livestock, it is desirable to develop herbicides and herbicide application methods that can obtain sufficient herbicidal effects while reducing the amount of chemicals used. For example, if a chemical with a stronger herbicidal effect is used as a herbicide, there is a possibility that the amount of the chemical itself can be reduced. However, such herbicides with too strong an effect are generally considered to have a high environmental impact. Also, as described in Patent Documents 1 and 2, it is conceivable to use a combination of a soil treatment herbicide and a foliage treatment herbicide to enhance the herbicidal effect, but it is unclear whether any of these herbicides can lead to a reduction in the amount of chemicals used as they are all based on chemicals.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Patent Document 2

Summary of the Invention

Problems to be Solved by the Invention

[0005] It is desirable to enhance the herbicidal effect of herbicides by using materials with low impact on humans, livestock, and the environment. The present invention aims to enhance the herbicidal effect of herbicides by using materials with less environmental impact.

Means for Solving the Problems

[0006] As a result of intensive studies by the present inventors, it has been found that the herbicidal effect can be enhanced by incorporating cellulose microfibers into existing soil-applied herbicides. That is, the present invention includes the following. (1) A herbicide composition comprising cellulose microfibers and a soil-applied herbicide. (2) The herbicide composition according to (1), wherein the cellulose microfibers are chemically modified cellulose microfibers. (3) The herbicide composition according to (1) or (2), wherein the soil-applied herbicide contains at least one selected from trifluralin, linuron, atrazine, dimethenamid, or diflufenican as an active ingredient. (4) The herbicide composition according to any one of (1) to (3), wherein the content of the soil-applied herbicide in the herbicide composition is 1 / 15 to 1 / 2 of the amount of the soil-applied herbicide recommended for the target plant. (5) The herbicide composition according to any one of (1) to (4), wherein the herbicide composition is a liquid agent containing water and contains cellulose microfibers in an amount of 0.1 to 10% by mass as a solid content. (6) The herbicide composition according to any one of (1) to (5), which contains the soil-applied herbicide in an amount of 0.005 to 200 parts by mass as an active ingredient amount with respect to 100 parts by mass of the solid content of the cellulose microfibers. (7) A method for spraying a herbicide composition, which includes spraying a herbicide composition containing cellulose microfibers, a soil-applied herbicide, and water onto the surface layer of the target soil so that the solid content of the cellulose microfibers is in the range of 0.1 to 100 g per square meter. 2 (8) With respect to the surface layer of the target soil, a cellulose microfiber dispersion liquid is applied per square meter. 2Spray so that the solid content of the cellulose microfibers ranges from 0.1 to 100 g per unit area, and spray a soil treatment type herbicide before or after spraying the cellulose microfiber dispersion. A method for spraying a herbicide, comprising the above. (9) The spraying method according to (7) or (8), further comprising drying the soil surface for 1 hour or more after spraying the cellulose microfibers and the soil treatment type herbicide.

Advantages of the Invention

[0007] Microfine cellulose fibers are natural-derived components and have a small environmental impact. According to the present invention, by using cellulose microfibers with a small environmental impact, the herbicidal effect of existing soil treatment type herbicides can be enhanced. As a result, for example, it becomes possible to obtain a herbicidal effect equivalent to that obtained when using the normally recommended amount while reducing the amount of the soil treatment type herbicide used. The reason why the herbicidal effect of the soil treatment type herbicide is enhanced by the combined use of cellulose microfibers is not clear, but the present inventors presume as follows: Soil treatment type herbicides stay on the surface layer of the soil after being sprayed and inhibit the germination and growth of weeds by being taken up from the young shoots and roots when the weeds germinate and grow. However, over time after spraying, they gradually penetrate deeper into the soil or are washed away by rain or the like, and are gradually lost from the surface layer, resulting in a reduction in the herbicidal effect. In particular, when the amount of the herbicide used is reduced, the amount of the herbicide staying on the surface layer decreases, and the herbicidal effect is reduced. On the other hand, by combining cellulose microfibers with a soil treatment type herbicide according to the present invention, the binding property between the herbicide and the soil is increased, making it difficult for the herbicide to be lost from the soil surface layer, maintaining the herbicidal effect for a longer period, and enabling the herbicidal effect to be exhibited even with a small amount of the herbicide.

Brief Description of the Drawings

[0008]

Figure 1

Figure 2

Embodiments for Carrying Out the Invention

[0009] The present invention relates to a herbicide composition containing cellulose microfibers and a soil treatment agent. In the present invention, by using cellulose microfibers in combination with a conventional soil treatment type herbicide, the herbicidal effect of the soil treatment type herbicide can be enhanced.

[0010] (Soil treatment type herbicide) A soil treatment type herbicide is an agent that, among herbicides, is sprayed on the soil surface to absorb the active ingredient from young shoots and young roots immediately after germination to suppress germination, or to absorb the active ingredient from the roots of weeds to cause them to wither. The soil treatment type herbicide used in the present invention may be an existing one such as a commercially available product. The active ingredient of the soil treatment type herbicide may be any one that can exhibit a herbicidal effect when sprayed on the soil, and is not particularly limited. For example, trifluralin, linuron, atrazine, dimethenamid, or diflufenican can be mentioned as preferred examples. These may be used alone or in combination of multiple types. The soil treatment type herbicide includes, for example, solid agents such as granular ones, and liquid agents or emulsions, and any dosage form may be used.

[0011] (Cellulose microfibers) The cellulose microfibers used in the present invention are microfibers made from cellulose as a raw material. The average fiber diameter of the cellulose microfibers is not particularly limited, but is about 2 nm to 10 μm. The cellulose microfibers may be fibrillated so as to have an average fiber diameter of, for example, about 1 μm to 10 μm, preferably about 3 μm to 7 μm, or may be finely fibrillated so as to have an average fiber diameter of 2 nm to 1 μm, preferably 3 nm to 500 nm, more preferably 3 nm to 100 nm, and even more preferably about 3 nm to 50 nm. The average fiber diameter and average fiber length of the cellulose microfibers can be obtained by appropriately selecting and using a fiber tester manufactured by ABB Ltd., a fractionator manufactured by Valmet, a scanning electron microscope (SEM), an atomic force microscope (AFM), or a transmission electron microscope (TEM) according to the size of the fiber diameter, and averaging the fiber diameter and fiber length obtained from the results of observing each fiber. The cellulose microfibers can be produced by fibrillating a cellulose raw material.

[0012] The aspect ratio of the cellulose microfibers used in the present invention is preferably 10 or more, more preferably 15 or more, and even more preferably 20 or more. The upper limit of the aspect ratio is not particularly limited, but is preferably 1000 or less, more preferably 500 or less, and even more preferably 300 or less. The aspect ratio can be calculated by the following formula: Aspect ratio = average fiber length / average fiber diameter The cellulose raw material serving as the raw material for cellulose microfibrils only needs to contain cellulose and is not particularly limited. For example, cellulose raw materials derived from plants (e.g., wood, bamboo, hemp, jute, kenaf, agricultural waste residues, cloth, pulp (softwood unbleached kraft pulp (NUKP), softwood bleached kraft pulp (NBKP), hardwood unbleached kraft pulp (LUKP), hardwood bleached kraft pulp (LBKP), sun-dried kraft pulp (BKP), softwood unbleached sulfite pulp (NUSP), softwood bleached sulfite pulp (NBSP), thermomechanical pulp (TMP), recycled pulp, waste paper, etc.)), cellulose raw materials derived from animals (e.g., tunicates), cellulose raw materials derived from algae, cellulose raw materials derived from microorganisms (e.g., acetic acid bacteria (Acetobacter)), cellulose raw materials derived from microbial products, etc. can be mentioned. As the cellulose raw material, any of these may be used, or a combination of two or more types may be used, but preferably a cellulose raw material derived from plants or microorganisms, and more preferably a cellulose raw material derived from plants.

[0013] Cellulose has three hydroxyl groups per glucose unit and can undergo various chemical modifications. From the viewpoint of promoting the progress of fibrillation, it is preferable to use chemically modified cellulose microfibrils produced by fibrillation of a cellulose raw material (chemically modified cellulose) obtained by chemical modification.

[0014] As the chemical modification, anionic modification for introducing an anionic group into cellulose is preferable. Specifically, anionic modification means introducing an anionic group into the pyranose ring by an oxidation or substitution reaction. In the present invention, the oxidation reaction refers to a reaction of oxidizing the C6 position of the pyranose ring to a carboxyl group. Further, in the present invention, the substitution reaction refers to a reaction of introducing an anionic group into the pyranose ring by a substitution reaction other than the oxidation. Examples of anionic modification include oxidation (carboxylation), carboxyalkylation (e.g., carboxymethylation), esterification, etc. Among them, oxidation (carboxylation) and carboxymethylation are more preferable.

[0015] Examples of the chemically modified cellulose microfibrils include TEMPO-oxidized cellulose microfibrils, ozone-oxidized cellulose microfibrils, carboxyalkylated cellulose microfibrils, carboxymethylated cellulose microfibrils, phosphate-esterified cellulose microfibrils, phosphite-esterified cellulose microfibrils, cationized cellulose microfibrils, sulfonated cellulose microfibrils, xanthated cellulose microfibrils, etc. Among them, TEMPO-oxidized cellulose microfibrils and carboxymethylated cellulose microfibrils are more preferred.

[0016] Cellulose microfibrils oxidized (also referred to as "carboxylated cellulose microfibrils"), which are an example of the chemically modified cellulose microfibrils, are obtained by oxidizing (carboxylating) the above-mentioned cellulose raw material by a known method to form oxidized cellulose fibers and then defibrating them. As an example of the oxidation (carboxylation) method, a method of oxidizing the cellulose raw material in water using an oxidizing agent in the presence of an N-oxyl compound and a compound selected from the group consisting of bromides, iodides, and mixtures thereof can be mentioned. By this oxidation reaction, the C6 position of the glucopyranose ring on the cellulose surface is selectively oxidized, and cellulose fibers (TEMPO-oxidized cellulose fibers) having an aldehyde group, a carboxy group (-COOH) or a carboxylate group (-COO ― ) on the surface are obtained. The TEMPO-oxidized cellulose microfibrils can be obtained by defibrating the TEMPO-oxidized cellulose fibers by the method described below.

[0017] An N-oxyl compound refers to a compound that can generate a nitroxyl radical. Any compound can be used as the N-oxyl compound as long as it can promote the target oxidation reaction. For example, 2,2,6,6-tetramethylpiperidine-1-oxyl radical (TEMPO) and its derivatives (such as 4-hydroxy TEMPO) can be mentioned. The amount of the N-oxyl compound used only needs to be a catalytic amount that can oxidize the cellulose raw material and is not particularly limited. For example, for 1 g of absolutely dry cellulose raw material, 0.01 - 10 mmol is preferred, 0.01 - 1 mmol is more preferred, and 0.01 - 0.5 mmol is even more preferred. Also, about 0.1 - 4 mmol / L is good for the reaction system.

[0018] A bromide is a compound containing bromine, and examples thereof include alkali metal bromides that can dissociate and ionize in water. Also, an iodide is a compound containing iodine, and examples thereof include alkali metal iodides. The amount of the bromide or iodide used can be selected within a range that can promote the oxidation reaction. The total amount of the bromide and iodide is, for example, preferably 0.1 - 100 mmol, more preferably 0.1 - 10 mmol, and even more preferably 0.5 - 5 mmol with respect to 1 g of absolutely dry cellulose raw material.

[0019] As the oxidizing agent, known ones can be used. For example, halogen, hypohalous acid, halous acid, perhalic acid or their salts, halogen oxides, peroxides, etc. can be used. Among them, sodium hypochlorite, which is inexpensive and has a low environmental impact, is preferred. The appropriate amount of the oxidizing agent used is, for example, preferably 0.5 - 500 mmol, more preferably 0.5 - 50 mmol, and even more preferably 2.5 - 25 mmol with respect to 1 g of absolutely dry cellulose raw material. Also, for example, 1 - 40 mol is preferred with respect to 1 mol of the N-oxyl compound.

[0020] Even under relatively mild conditions, the oxidation process of the cellulose raw material can proceed efficiently. Therefore, the reaction temperature is preferably 4 to 40 °C, and it may also be at room temperature of about 15 to 30 °C. As carboxyl groups are generated in the cellulose during the reaction, the pH of the reaction solution decreases. In order to allow the oxidation reaction to proceed efficiently, it is preferable to add an alkaline solution such as an aqueous sodium hydroxide solution to the reaction system as needed to maintain the pH of the reaction solution at 9 to 12, preferably about 10 to 11. The reaction medium is preferably water in view of ease of handling and low likelihood of side reactions. The reaction time in the oxidation reaction can be appropriately set according to the degree of progress of oxidation, and is usually 0.5 to 6 hours, for example, about 0.5 to 4 hours. The concentration of the cellulose raw material during the oxidation reaction is not particularly limited, but is preferably 5% by mass or less.

[0021] Also, the oxidation reaction may be carried out in two steps. For example, by oxidizing the oxidized cellulose obtained by filtration after completion of the first-stage reaction again under the same or different reaction conditions, carboxyl groups can be efficiently introduced into the cellulose raw material without being inhibited by the salts by-produced in the first-stage reaction.

[0022] As another example of the oxidation (carboxylation) method, a method of oxidizing by ozone treatment can be mentioned, by which ozone-oxidized cellulose fibers can be obtained. By defibrating the ozone-oxidized cellulose fibers by the method described later, ozone-oxidized cellulose microfibers can be obtained. Among ozone-oxidized cellulose microfibers and TEMPO-oxidized cellulose microfibers, it is preferable to use TEMPO-oxidized cellulose microfibers.

[0023] The amount of carboxyl groups contained in the oxidized cellulose microfibrils obtained by defibrating oxidized cellulose fibers, relative to the absolute dry mass of the cellulose microfibrils, is preferably 0.6 mmol / g or more, more preferably 0.8 mmol / g or more, still more preferably 1.0 mmol / g or more. The upper limit is preferably 2.2 mmol / g or less, more preferably 2.0 mmol / g or less, still more preferably 1.8 mmol / g or less. Therefore, 0.6 mmol / g to 2.2 mmol / g is preferable, 0.8 mmol / g to 2.0 mmol / g is more preferable, and 1.0 mmol / g to 1.8 mmol / g is still more preferable.

[0024] The amount of carboxyl groups in the oxidized cellulose fibers can be measured by the following procedure: Prepare 60 mL of a 0.5 mass% slurry (aqueous dispersion) of oxidized cellulose fibers, add 0.1 M hydrochloric acid aqueous solution to adjust the pH to 2.5, and then dropwise add 0.05 N sodium hydroxide aqueous solution to measure the electrical conductivity until the pH reaches 11. From the amount of sodium hydroxide (a) consumed in the stage of neutralizing the weak acid where the change in electrical conductivity is gentle, the amount of carboxyl groups is calculated using the following formula. Amount of carboxyl groups [mmol / g of oxidized cellulose fibers] = a [mL] × 0.05 / mass of oxidized cellulose fibers [g] The amount of carboxyl groups in the oxidized cellulose fibers can be adjusted by controlling reaction conditions such as the addition amount of the above-mentioned oxidizing agent and the reaction time. The amount of carboxyl groups in the oxidized cellulose fibers and the amount of carboxyl groups when the oxidized cellulose fibers are defibrated into oxidized cellulose microfibrils are usually the same.

[0025] In the oxidized cellulose fibers obtained in the above process, the carboxyl groups introduced into the cellulose raw material are usually in the form of alkali metal salts such as sodium salts (this is called the "salt form"). Before the defibrination step, the alkali metal salt of the oxidized cellulose fibers may be substituted with other cation salts such as phosphonium salts, imidazolinium salts, ammonium salts, and sulfonium salts. The substitution can be carried out by known methods.

[0026] An example of chemically modified cellulose microfibrils, carboxyalkylated cellulose microfibrils, preferably carboxymethylated cellulose microfibrils, may be obtained by known methods or commercial products may be used. The degree of carboxyalkyl substitution per anhydroglucose unit of cellulose is preferably less than 0.60. Further, when the anionic group is a carboxymethyl group, the degree of carboxymethyl substitution is preferably less than 0.60. When the substitution degree is 0.60 or more, the crystallinity decreases and the ratio of the dissolved component increases, so that the function as microfibrils may be lost. The lower limit of the degree of carboxyalkyl substitution is preferably 0.01 or more. Considering the operability, the substitution degree is particularly preferably 0.02 to 0.50, and more preferably 0.10 to 0.30. As an example of a method for producing carboxyalkylated cellulose fibers as a raw material for such carboxyalkylated cellulose microfibrils, a method including the following steps may be mentioned. The modification is a modification by a substitution reaction. The carboxymethylated cellulose fiber will be described as an example.

[0027] i) A step of mixing a cellulose raw material, a solvent, and a mercerizing agent, and performing a mercerizing treatment at a reaction temperature of 0 to 70°C, preferably 10 to 60°C, and a reaction time of 15 minutes to 8 hours, preferably 30 minutes to 7 hours, and ii) Next, a step of adding a carboxymethylating agent in an amount of 0.05 to 10.0 moles per mole of glucose residue, and performing an etherification reaction at a reaction temperature of 30 to 90°C, preferably 40 to 80°C, and a reaction time of 30 minutes to 10 hours, preferably 1 hour to 4 hours.

[0028] As the solvent for the mercerization and etherification reactions, 3 to 20 mass times of water or a lower alcohol can be used, specifically, water, methanol, ethanol, n-propyl alcohol, isopropyl alcohol, n-butanol, isobutanol, tertiary butanol, etc. alone, or a mixed medium of two or more. When mixing a lower alcohol, the mixing ratio is 60 to 95% by mass. As the mercerizing agent, 0.5 to 20 moles per mole of anhydroglucose residue of the cellulose raw material of an alkali metal hydroxide, specifically sodium hydroxide or potassium hydroxide, can be used.

[0029] As described above, the degree of carboxymethyl substitution per glucose unit of cellulose is less than 0.60, preferably 0.01 or more and less than 0.60. By introducing carboxymethyl substituents into cellulose, the celluloses repel each other electrically. Therefore, the carboxymethylated cellulose fibers can be easily defibrated. Note that if the carboxymethyl substituent per glucose unit is less than 0.01, defibration may not be sufficient.

[0030] The degree of carboxymethyl substitution of carboxymethylated cellulose fibers can be measured by the following procedure: Precisely weigh about 2.0 g of carboxymethylated cellulose fibers (bone-dry) and place them in a 300 mL conical flask with a stopper. Add 100 mL of a solution prepared by adding 100 mL of special grade concentrated nitric acid to 1000 mL of nitric acid methanol, shake for 3 hours, and convert the salt-type carboxymethylated (CM) cellulose fibers into hydrogen-type CM cellulose fibers. Precisely weigh 1.5 - 2.0 g of hydrogen-type CM cellulose fibers (bone-dry) and place them in a 300 mL conical flask with a stopper. Moisten the hydrogen-type CM cellulose fibers with 15 mL of 80% methanol, add 100 mL of 0.1 N NaOH, and shake at room temperature for 3 hours. Using phenolphthalein as an indicator, back-titrate the excess NaOH with 0.1 N H 2 SO 4 Calculate the degree of carboxymethyl substitution (DS) using the following formula. A = [(100 × F’ - (0.1 N H 2 SO 4 )(mL) × F) × 0.1] / (bone-dry mass of hydrogen-type CM cellulose fibers (g)) DS = 0.162 × A / (1 - 0.058 × A) A: Amount of 1 N NaOH (mL) required for neutralizing 1 g of hydrogen-type CM cellulose fibers F’: Factor of 0.1 N H 2 SO 4 F: Factor of 0.1 N NaOH The degree of substitution in carboxymethylated cellulose fibers is usually the same as that in the case of carboxymethylated cellulose microfibers.

[0031] In the carboxyalkylated cellulose fibers obtained in the above process, the carboxyalkyl groups introduced into the cellulose raw material are usually in the form of alkali metal salts such as sodium salts (this is referred to as the "salt form"). Before the fibrillation step, the alkali metal salt of the carboxyalkylated cellulose fibers may be replaced with other cation salts such as phosphonium salts, imidazolinium salts, ammonium salts, and sulfonium salts. The substitution can be carried out by known methods.

[0032] Examples of methods for producing esterified cellulose fibers (e.g., phosphate esterified cellulose fibers, phosphite esterified cellulose fibers, etc.) which are raw materials for esterified cellulose microfibers, which are an example of chemically modified cellulose microfibers, include a method of mixing a powder or aqueous solution of a phosphoric acid compound with a cellulose raw material, a method of adding an aqueous solution of a phosphoric acid compound to a slurry of a cellulose raw material, and the like. Examples of phosphoric acid compounds include phosphoric acid, polyphosphoric acid, phosphorous acid, hypophosphorous acid, phosphonic acid, polyphosphonic acid, or esters thereof. These may be in the form of salts. Among these, compounds having a phosphate group are preferred because they are low-cost, easy to handle, and can introduce a phosphate group into the cellulose of pulp fibers to improve fibrillation efficiency. Examples of compounds having a phosphate group include phosphoric acid, sodium dihydrogen phosphate, disodium hydrogen phosphate, trisodium phosphate, sodium phosphite, potassium phosphite, sodium hypophosphite, potassium hypophosphite, sodium pyrophosphate, sodium metaphosphate, potassium dihydrogen phosphate, dipotassium hydrogen phosphate, tripotassium phosphate, potassium pyrophosphate, potassium metaphosphate, ammonium dihydrogen phosphate, diammonium hydrogen phosphate, triammonium phosphate, ammonium pyrophosphate, ammonium metaphosphate, and the like. These can be used alone or in combination of two or more to introduce a phosphate group. Among these, phosphoric acid, sodium salts of phosphoric acid, potassium salts of phosphoric acid, and ammonium salts of phosphoric acid are preferred from the viewpoints of high efficiency of phosphate group introduction, easy fibrillation in the following fibrillation step, and easy industrial application. In particular, sodium dihydrogen phosphate and disodium hydrogen phosphate are preferred. Further, since the reaction can proceed uniformly and the efficiency of phosphate group introduction is high, it is desirable to use the phosphoric acid compound as an aqueous solution. The pH of the aqueous solution of the phosphoric acid compound is preferably 7 or less because the efficiency of phosphate group introduction is high, but preferably pH 3 to 7 from the viewpoint of suppressing hydrolysis of cellulose fibers.

[0033] As a specific example of a method for producing a phosphoric acid esterified cellulose fiber, the following method can be cited. A phosphoric acid-based compound is added to a suspension of a cellulose raw material having a solid content concentration of 0.1 to 10% by mass while stirring to introduce a phosphate group into the cellulose. When the cellulose raw material is 100 parts by mass, the addition amount of the phosphoric acid-based compound is preferably 0.2 to 500 parts by mass, more preferably 1 to 400 parts by mass, in terms of the amount of phosphorus element. If the proportion of the phosphoric acid-based compound is equal to or higher than the lower limit value, the yield of the cellulose microfiber can be further improved. However, if it exceeds the upper limit value, the effect of improving the yield reaches a plateau, which is not preferable from the cost aspect.

[0034] In addition to the phosphoric acid compound, powders or aqueous solutions of other compounds may be mixed. The other compounds are not particularly limited, but nitrogen-containing compounds showing basicity are preferred. Here, "basicity" is defined as the aqueous solution showing a peach to red color in the presence of a phenolphthalein indicator, or the pH of the aqueous solution being greater than 7. The nitrogen-containing compound showing basicity is not particularly limited as long as the effects of the present invention are not impaired, but a compound having an amino group is preferred. For example, urea, methylamine, ethylamine, trimethylamine, triethylamine, monoethanolamine, diethanolamine, triethanolamine, pyridine, ethylenediamine, hexamethylenediamine, etc. may be mentioned. Among them, urea, which is low-cost and easy to handle, is preferred. The addition amount of the other compound is preferably 2 to 1000 parts by mass, more preferably 100 to 700 parts by mass, based on 100 parts by mass of the solid content of the cellulose raw material. The reaction temperature is preferably 0 to 95°C, more preferably 30 to 90°C. The reaction time is not particularly limited, but is about 1 to 600 minutes, more preferably 30 to 480 minutes. When the conditions of the esterification reaction are within these ranges, it is possible to prevent the cellulose from being excessively esterified and becoming easily soluble, and the yield of the phosphoric acid esterified cellulose becomes good. After dehydrating the obtained phosphoric acid esterified cellulose suspension, from the viewpoint of suppressing the hydrolysis of cellulose, it is preferable to perform heat treatment at 100 to 170°C. Further, while water is contained during the heat treatment, it is preferable to heat at 130°C or lower, preferably 110°C or lower, and after removing the water, perform heat treatment at 100 to 170°C.

[0035] The degree of substitution of phosphate groups per glucose unit of the phosphorylated cellulose fiber is preferably 0.001 or more and less than 0.40. By introducing a phosphate group substituent into cellulose, the celluloses repel each other electrically. Therefore, the cellulose into which the phosphate group has been introduced can be easily defibrated. If the degree of substitution of phosphate groups per glucose unit is less than 0.001, it cannot be sufficiently defibrated. On the other hand, if the degree of substitution of phosphate groups per glucose unit is greater than 0.40, it may swell or dissolve, and thus may not be obtained as microfibrils. In order to perform defibrillation efficiently, it is preferable that the phosphorylated cellulose raw material obtained above is boiled and then subjected to a washing treatment such as washing with cold water. These modifications by esterification are modifications by substitution reaction. The degree of substitution in the phosphorylated cellulose fiber and the degree of substitution when it is made into phosphorylated cellulose microfibrils are usually the same.

[0036] In the phosphorylated cellulose fiber obtained in the above step, the phosphate group introduced into the cellulose raw material is usually in the form of an alkali metal salt such as sodium salt (this is referred to as the "salt form"). Before the defibrillation step, the alkali metal salt of the phosphorylated cellulose fiber may be substituted with another cation salt such as a phosphonium salt, an imidazolinium salt, an ammonium salt, or a sulfonium salt. The substitution can be carried out by a known method.

[0037] The apparatus for defibrating cellulose raw materials or chemically modified cellulose raw materials (chemically modified cellulose fibers) is not particularly limited. For example, it is preferable to apply a shearing force to the raw materials (usually an aqueous dispersion of the raw materials) using a defibrating apparatus such as a high-speed rotary type, a colloid mill type, a high-pressure type, a roll mill type, an ultrasonic type, etc., or a refiner, a cavitation jet apparatus, etc. In particular, it is preferable to use a cavitation jet apparatus that can efficiently defibrate at a pressure of about 7 MPa, or a wet high-pressure or ultra-high pressure homogenizer that can apply a pressure of 50 MPa or more to the raw materials (usually an aqueous dispersion) and apply a strong shearing force. Also, prior to the defibrating and dispersing treatment, a pretreatment can be performed as necessary. The pretreatment can be carried out using known mixing, stirring, emulsifying, and dispersing apparatuses such as a high-speed shearing mixer. The number of passes (treatment times) in the defibrating apparatus may be once or two or more times, and two or more times are preferable.

[0038] When performing defibrating, usually first, a cellulose raw material or a chemically modified cellulose fiber is dispersed in a dispersion medium to prepare a dispersion. The dispersion medium is not particularly limited as long as it can disperse the cellulose raw material or the chemically modified cellulose fiber, and examples thereof include water, an organic solvent, and a mixed solvent thereof.

[0039] The solid content concentration of the cellulose raw material or the chemically modified cellulose fiber in the dispersion is usually 0.1% by mass or more, preferably 0.2% by mass or more, and more preferably 0.3% by mass or more. Thereby, the amount of the liquid with respect to the amount of the solid content becomes an appropriate amount and it is efficient. The upper limit is usually 10% by mass or less, preferably 6% by mass or less. Thereby, fluidity can be maintained.

[0040] Prior to defibrating, a pretreatment may be performed as necessary. The pretreatment may be carried out using a mixing, stirring, emulsifying, and dispersing apparatus such as a high-speed shearing mixer. In the herbicide composition of the present invention, the cellulose microfibers are preferably in the form of a dispersion dispersed in a dispersion medium. As the dispersion medium, an aqueous dispersion medium is preferred, and examples thereof include water and a mixed medium of water and a lower alcohol such as methanol, ethanol, n-propyl alcohol, isopropyl alcohol, n-butanol, isobutanol, and tertiary butanol. From the viewpoint of reducing the environmental burden, the dispersion medium is preferably water.

[0041] The cellulose microfibers used in the herbicide composition of the present invention preferably have a B-type viscosity (25°C, 60 rpm) of 10 mPa·s or more, more preferably 100 mPa·s, and even more preferably 500 mPa·s or more when made into an aqueous dispersion with a solid content of 0.5% by mass. In particular, cellulose microfibers having a viscosity of 100 mPa·s or more have high water retention, and the water contained in the microfibers is less likely to leak into the soil immediately. Therefore, the gel-like fine cellulose fibers are likely to be retained on the soil for a long period of time, and the herbicidal effect can be maintained for a longer time.

[0042] (Herbicide composition) The herbicide composition of the present invention contains cellulose microfibers and a soil treatment type herbicide. From the viewpoints of high herbicidal effect, ease of spraying, and improvement of the stability of cellulose microfibers, the herbicide composition is preferably a liquid agent further containing at least water. Examples of the liquid agent include an aqueous liquid agent and an emulsion containing water and an emulsifier. The liquid agent is not limited thereto, and can be obtained, for example, by mixing a dispersion (dispersion liquid of cellulose microfibers) obtained by dispersing cellulose microfibers in a liquid dispersion medium with a soil treatment type herbicide in the form of granules, liquid agent, or emulsion.

[0043] The amount of the soil treatment type herbicide in the herbicide composition is an amount that can achieve a herbicidal effect when formulated into a herbicide composition. Usually, commercially available herbicides such as soil treatment type herbicides are attached with instructions or indications of the recommended application rates according to the plants to be weeded. In the present invention, by using cellulose microfibers in combination with the soil treatment type herbicide, the herbicidal effect of the soil treatment type herbicide can be enhanced. Therefore, the amount of the soil treatment type herbicide used (sprayed onto the soil surface) in the herbicide composition may be less than the recommended application rate. For example, it may be an amount of about 1 / 15 to 1 / 2 of the recommended application rate, or an amount of about 1 / 10 to 1 / 5. For example, but not limited thereto, the standard application rate (estimated) of the soil treatment type herbicide is 0.07 to 0.15 g / m 2 2. The amount of the soil treatment type herbicide used (sprayed onto the soil surface) in the herbicide composition of the present application may be less than the recommended amount, for example, it may be an amount of about 1 / 100 to 1 / 2 of the recommended amount, or an amount of about 1 / 50 to 1 / 3, or an amount of about 1 / 20 to 1 / 4, or an amount of about 1 / 10 to 1 / 5.

[0044] Also, the amount of the soil treatment type herbicide in the herbicide composition is not limited thereto, and for example, it may be an amount of about 0.005 to 200 parts by mass in terms of the active ingredient amount with respect to 100 parts by mass of the solid content of cellulose microfibers. Preferably, it is 0.01 to 100 parts by mass, and more preferably, it is 0.01 to 50 parts by mass.

[0045] As described above, the herbicide composition of the present invention is preferably a liquid agent containing water, and the amount of cellulose microfibers in the herbicide composition when spraying onto the soil surface is preferably an amount of 0.1 to 10% by mass in terms of the dry mass (solid content) of cellulose microfibers. More preferably, it is 0.1 to 5% by mass, and even more preferably, it is about 0.2 to 3% by mass. When the amount is within this range, the herbicide composition has an appropriate viscosity and is easy to spray.

[0046] The herbicide composition of the present invention may contain various additives other than the above-mentioned cellulose microfibers and soil treatment type herbicides as long as the effects of the present invention are not inhibited. (Plants to be weeded) The plants (weeds) that can be weeded with the herbicide composition of the present invention are not particularly limited. Any plants that can be weeded with a soil treatment type herbicide can be targeted. Examples of weed species include, for example, barnyard grasses, sedges, Japanese stiltgrass, annual bluegrass, goosegrass, redroot pigweed, common purslane, chickweed, shepherd's purse, common lambsquarters, giant reed, prickly sida, kudzu, Japanese knotweed, mugwort, umbrella sedge, giantreed, sedges, cinquefoil, and bluegrass. In addition, vine-like weeds such as wild yam, devil's tongue, six-leaved glorybower, morning glory, bindweed, wild mustard, purple morning glory, and Japanese bindweed can also be targeted for weeding. In particular, wild yam forms tubers underground and produces rigid stems above ground, making it difficult to simply pull out. If one tries to pull it out forcefully, the stem may break in the middle or the tuber may break, making it difficult to completely remove. One of the advantages of the present invention is that by using the herbicide composition of the present invention, plants that have conventionally been laborious to weed, such as wild yam, can be efficiently weeded.

[0047] (Spraying method) As described above, the herbicide composition of the present invention is preferably a liquid agent containing water. A herbicide composition containing at least cellulose microfibers, a soil treatment type herbicide, and water is sprayed onto the surface layer of the target soil. Examples of the spraying method of the liquid herbicide composition include a spraying method using instruments such as a sprayer or a high-pressure washer, and a method of manually sprinkling the necessary parts using a watering can or the like.

[0048] The spraying amount of the herbicide composition of the present invention is not particularly limited, but an especially effective spraying amount is such that the cellulose microfibers are uniformly sprayed at 0.1 to 100 g as a solid content on 1 m 2 of soil. More preferably, on 1 m 2It is 1 to 20 g in terms of the solid content of cellulose microfibers around. The amount of the soil treatment type herbicide to be sprayed may be less than the amount recommended for the plants to be weeded as described above. For example, it may be an amount about 1 / 15 to 1 / 2 of the recommended amount, or may be an amount about 1 / 10 to 1 / 5 of the recommended amount. Also, for the soil of 1 m 2 in the whole herbicide composition, it is preferably about 0.5 to 5 L, more preferably 1 to 3 L. If the spraying amount is too much, it takes time for spraying and also costs, so it is not preferable. If the spraying amount is too little, it is difficult to exhibit the weeding effect.

[0049] Alternatively, as another spraying method, the cellulose microfiber dispersion liquid and the soil treatment type herbicide may be sprayed separately on the surface layer of the soil. The order of spraying in this case is not particularly limited. The cellulose microfiber dispersion liquid may be sprayed first and then the soil treatment type herbicide may be sprayed, or the soil treatment type herbicide may be sprayed first and then the cellulose microfiber dispersion liquid may be sprayed. In this case, the soil treatment type herbicide may be in the form of a solid agent such as granules, or may be in the form of a liquid agent or emulsion. The respective spraying amounts when the cellulose microfiber dispersion liquid and the soil treatment type herbicide are sprayed separately without being mixed in advance are not particularly limited, but it is preferable to spray the cellulose microfiber so that it becomes 0.1 to 100 g as the solid content on 1 m 2 of the soil, and more preferably 1 to 20 g. Also, the spraying amount of the soil treatment type herbicide may be less than the amount recommended for the plants to be weeded, for example, it may be an amount about 1 / 15 to 1 / 2 of the recommended amount, or may be an amount about 1 / 10 to 1 / 5 of the recommended amount. When the cellulose microfiber dispersion liquid and the soil treatment type herbicide are sprayed separately, it is preferable to spray the other one without much time lapse after spraying one. For example, it is preferable to spray the other one within 3 hours after spraying one, and more preferably within 1 hour.

[0050] It is preferable to dry the soil surface for 1 hour or more after mixing the cellulose microfibers and the soil treatment type herbicide or spraying them separately. The means of drying is not particularly limited. When spraying on outdoor soil, avoid spraying on rainy days and let it dry by leaving it as it is.

[0051] The herbicide composition and spraying method of the present invention can be applied to any land where weeds grow. For example, but not limited to, fields, lawns, wastelands, orchards, tea gardens, construction sites, flower beds, soil near street trees, parks, green spaces, etc. When spraying, although not limited to this, it is preferable to remove weeds in advance because it is easy to obtain effects. Also, although not limited to this, it is preferable to spray before the weeds germinate, and it is more preferable to spray by the 5-leaf stage after the weeds have germinated. The spraying frequency can be adjusted according to the type of plants to be weeded and the degree of plant germination, and is not particularly limited, but generally it is preferably carried out regularly, for example, at a frequency of about 1 to 3 times a year, because the weeding effect is likely to be maintained for a long time.

Examples

[0052] Hereinafter, the present invention will be described in more detail with reference to examples, but the present invention is not limited thereto. (Production of oxidized cellulose microfibers) 5.00 g (bone-dry) of bleached and unbeat pulp (brightness 85%) derived from coniferous trees was added to 500 mL of an aqueous solution in which 39 mg of TEMPO (Sigma Aldrich) and 514 g of sodium bromide were dissolved, and stirred until the pulp was uniformly dispersed. An aqueous sodium hypochlorite solution was added to the reaction system to a concentration of 6.0 mmol / g to initiate the oxidation reaction. During the reaction, the pH of the system decreased, but 3 M aqueous sodium hydroxide solution was sequentially added to adjust the pH to 10. The reaction was terminated when the sodium hypochlorite was consumed and the pH in the system no longer changed. After the reaction, the mixture was acidified with hydrochloric acid, filtered through a glass filter to separate the pulp, and the pulp was thoroughly washed with water to obtain oxidized pulp (oxidized cellulose fibers). The yield at this time was 90%, the time required for the oxidation reaction was 90 minutes, and the amount of carboxyl groups was 1.6 mmol / g.

[0053] The oxidized cellulose fibers obtained in the above process were adjusted to 2.5% (w / v) with water and treated 10 times with a cavitation jet device at 7 MPa to obtain an aqueous dispersion of oxidized cellulose microfibrils. The obtained oxidized cellulose microfibrils had an average fiber diameter of 15 nm and an aspect ratio of 262.

[0054] (Production of Herbicidal Composition) An aqueous dispersion of oxidized cellulose microfibrils (solid content 0.5 mass%) was prepared. To this, a soil treatment type herbicide containing trifluralin as an active ingredient (Treflanocide emulsion manufactured by Nissan Chemical Industries, Ltd.) was mixed to the recommended amount at the time of spraying (0.4 mL / m 2 , approximately 0.18 g / m in terms of the amount of active ingredient 2 ) to prepare a mixture (cellulose + appropriate amount of herbicide group). Also, a mixture in which the soil treatment type herbicide was mixed in an amount of 1 / 10 of the above recommended amount was prepared (cellulose + herbicide dilution group).

[0055] Also, for comparison, an aqueous dispersion of the above oxidized cellulose microfibrils (solid content 0.5 mass%) without the soil treatment type herbicide was prepared (cellulose alone group). (Verification of Effect on Yamanoimo 1) Red soil was put into 9-cm pots and dried. After drying, 10 tubers of Japanese yam about 1 cm in size were sown in each pot, and red soil was lightly sprinkled on top. Each of the compositions prepared above (cellulose + appropriate amount of herbicide section, cellulose + diluted herbicide section, cellulose alone section) was sprayed on each pot at a rate of 2 L per 1 m 2 area. Also, as a control, a section where 2 L of water was sprayed per 1 m 2 area was also prepared. Each treatment was sprayed on 5 pots per area. After spraying, it was dried outdoors for 2 hours and then dried in an incubator set at 20°C. After drying, appropriate bottom watering was carried out, and while watering up to the soil surface, it was cultivated in an incubator for 10 days, and the number of germinations of Japanese yam was counted. The incubator was set to a 12-hour day length. One day, 6 days, and 10 days after starting cultivation in the incubator, the average value of the number of germinations of 4 pots was determined for each area. The results are shown in Figure 1.

[0056] From the results in Figure 1, it can be seen that in the sections where cellulose microfibrils and a soil treatment type herbicide were mixed (cellulose + appropriate amount of herbicide section and cellulose + diluted herbicide section), the germination of Japanese yam was significantly suppressed compared to the control and the cellulose alone section containing only cellulose microfibrils. In particular, it can be seen that even when the amount of the soil treatment type herbicide was diluted to 1 / 10 of the recommended amount (cellulose + diluted herbicide section), a herbicidal effect equivalent to that of the appropriate amount section was obtained.

[0057] (Verification of the effect on Japanese yam 2) A liquid containing the soil treatment type herbicide used in the above-mentioned "Verification of the effect on Japanese yam 1" at the recommended amount was prepared. Liquids diluted to 1 / 10, 1 / 20, and 1 / 100 of this liquid were respectively prepared. Also, for each of these liquids, a liquid in which oxidized cellulose microfibrils were mixed in an amount of 0.5% by mass of the solid content was prepared.

[0058] Soil was put into 6-cm pots, 10 tubers of Japanese yam about 1 cm in size were sown in each pot, and soil was lightly sprinkled on top. Each of the liquids prepared above was sprayed on each pot at a rate of 2 L per 1 m 2 area. Also, a liquid without the mixed herbicide was sprayed at a rate of 2 L per 1 m 2A plot was also prepared where spraying was carried out at a rate of 2 L per area. Spraying was carried out on 4 pots per plot. After spraying, it was dried outdoors for 12 hours. Then, it was placed in an incubator set at 20°C. From 3 days later, bottom irrigation was carried out, and while watering up to the soil surface, cultivation was carried out in the incubator for 10 days, and the number of germinations of yam tubers was counted. The incubator was set to a day length of 12 hours. The germination rate of each plot was calculated with the number of germinations in the plot without the mixed herbicide set as 100%. The results are shown in Figure 2.

[0059] From the results in Figure 2, it can be seen that when the herbicide is diluted and used with respect to the recommended amount, the herbicidal effect decreases. However, when cellulose microfibers are mixed with the herbicide, a certain herbicidal effect can be obtained even if the amount of the herbicide is less than the recommended amount.

Claims

1. A herbicide composition comprising cellulose microfibers and a soil treatment type herbicide.

2. The herbicide composition according to claim 1, wherein the cellulose microfibers are chemically modified cellulose microfibers.

3. The herbicide composition according to claim 1 or 2, wherein the soil treatment type herbicide contains at least one selected from trifluralin, linuron, atrazine, dimethenamid, or diflufenican as an active ingredient.

4. The herbicide composition according to claim 1 or 2, wherein the content of the soil treatment type herbicide in the herbicide composition is 1 / 15 to 1 / 2 of the amount of the soil treatment type herbicide recommended for the target plant to be weeded.

5. The herbicide composition according to claim 1 or 2, wherein the herbicide composition is a liquid agent containing water, and contains cellulose microfibers in an amount of 0.1 to 10% by mass as a solid content.

6. The herbicide composition according to claim 1 or 2, containing the soil treatment type herbicide in an effective ingredient amount in the range of 0.005 to 200 parts by mass with respect to 100 parts by mass of the solid content of the cellulose microfibers.

7. A method for spraying a herbicide composition, which comprises spraying, onto the surface layer of a target soil, a herbicide composition containing cellulose microfibers, a soil treatment type herbicide, and water, such that the solid content of the cellulose microfibers is in the range of 0.1 to 100 g per meter square. ２ The spraying method of the herbicide composition further includes spraying such that the solid content of the cellulose microfibers is in the range of 0.1 to 100 g per meter square.

8. With respect to the surface layer of the target soil, spray a cellulose microfiber dispersion liquid so that the solid content of the cellulose microfiber becomes in the range of 0.1 to 100 g per 1 m ２ around, and Spraying a soil treatment type herbicide before or after spraying the cellulose microfiber dispersion A method for spraying a herbicide, comprising:

9. The spraying method according to claim 7 or 8, further comprising drying the soil surface for 1 hour or more after spraying the cellulose microfibers and the soil treatment type herbicide.

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