Additive for pesticide

Abstract

To provide an additive for a pesticide which is excellent in spreading property.SOLUTION: The present invention provides an additive for a pesticide and an additive for a pesticide intended for a paddy field or hydroponic culture, which contain sulfomethylated kraft lignin whose weight average molecular weight is 5,000-37,000 and whose organic S content is 1.3-5.1 mass%. The sulfomethylated kraft lignin preferably satisfies at least one selected from the following: 14% or less in terms of total yield of degradation products by alkaline nitrobenzene oxidation; a polydispersity of 1.5-4.7; and a weight average molecular weight of 5,000-23,000.SELECTED DRAWING: None

Description

[Technical Field]

[0001] The present invention relates to an agricultural chemical additive. [Background technology]

[0002] Lignin, one of the major components of plant cell walls, is isolated on a large scale by cooking for the purpose of pulping in the paper and pulp industry. The resulting lignin may be modified during cooking and is classified into kraft lignin, lignin sulfonates, etc., depending on the cooking method. Some lignin sulfonates are further chemically modified as needed and are used commercially on a large scale for various applications.

[0003] Patent Document 1 describes an agricultural chemical composition containing, as a surfactant, a lignin sulfonate having a purity of 85% by mass or more, which has a reducing sugar content of less than 5% by mass and a sugar sulfonic acid content of less than 6% by mass.

[0004] Patent Document 2 describes an aqueous suspension pesticide composition that contains, as essential ingredients, a low-melting pesticide active ingredient A, a lignosulfonate metal salt B, a sucrose fatty acid ester C, and a thickener, and that exhibits resistance to particle growth of the low-melting pesticide active ingredient. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Patent No. 6483857 [Patent Document 2] Patent No. 6189136 Summary of the Invention [Problem to be solved by the invention]

[0006] An important physical property of a pesticide formulation is spreadability. Spreadability generally refers to the property of a spreadable substance containing a pesticide ingredient dispersing in water and spreading uniformly and quickly. However, the pesticide composition of Patent Document 1 or the aqueous suspension pesticide composition of Patent Document 2 has insufficient spreadability, which may limit the areas in which they can be used.

[0007] An object of the present invention is to provide an agricultural chemical additive having excellent spreadability. [Means for solving the problem]

[0008] The present invention provides the following [1] to [7]. [1] A pesticide additive containing sulfomethylated kraft lignin having a weight-average molecular weight of 5,000 to 37,000 and an organic S content of 1.3 to 5.1% by mass. [2] The agricultural chemical additive according to [1], wherein the yield of total decomposition products by alkaline nitrobenzene oxidation of sulfomethylated kraft lignin is 14% or less. [3] The agricultural chemical additive according to [1] or [2], wherein the weight-average molecular weight of the sulfomethylated kraft lignin is 5,000 to 23,000. [4] The agricultural chemical additive according to any one of [1] to [3], wherein the polydispersity of the sulfomethylated kraft lignin is 1.5 to 4.7. [5] The pesticide additive according to any one of [1] to [4], which is for use in solid pesticides. [6] The pesticide additive according to any one of [1] to [4], which is for use in liquid pesticides. [7] The pesticide additive according to any one of [1] to [4], which is for use in pesticides for paddy field or hydroponic cultivation. [Effects of the Invention]

[0009] According to the present invention, an agricultural chemical additive having excellent spreadability can be provided, and when blended with an agricultural chemical, the dispersibility of the components in the agricultural chemical can be improved. DETAILED DESCRIPTION OF THE INVENTION

[0010] [1. Pesticide additives] The agricultural additive of the present invention contains sulfomethylated kraft lignin.

[0011] [Sulfomethylated Kraft Lignin] In this specification, sulfomethylated kraft lignin is a reaction product obtained by sulfomethylating kraft lignin as a raw material. In the sulfomethylation reaction of kraft lignin, a sulfo group (-SO3M; M is a hydrogen atom or a metal salt) is generally introduced at the α-position of the C6-C3 unit of the lignin (generally referred to as sulfonation), and in the case of guaiacyl lignin (G nucleus), a sulfomethyl group (-CH3SO3M; M is a hydrogen atom or a metal salt) is introduced at the 5-position of the aromatic nucleus.

[0012] -Organic S content- The organic S (sulfur atom) content of the sulfomethylated kraft lignin is preferably 1.3% by mass or more, more preferably 1.4% by mass or more, and even more preferably 1.5% by mass or more. This allows an agricultural additive with excellent spreadability to be obtained. The upper limit is preferably 5.1% by mass or less, more preferably 5.0% by mass or less, and even more preferably 4.9% by mass or less. This allows the effects of the present invention to be suitably exhibited. Therefore, the organic S content is preferably 1.3 to 5.1% by mass, more preferably 1.4 to 5.0% by mass, and even more preferably 1.5 to 4.9% by mass.

[0013] The organic S content can be used as an indicator of the degree of sulfomethylation in sulfomethylated lignin. The organic S content can be calculated by subtracting the inorganic S content (both as a percentage of the solid content of sulfomethylated lignin) from the total S content of sulfomethylated lignin. The total S content and inorganic S content can be measured by ICP atomic emission spectroscopy and ion chromatography, respectively.

[0014] -Weight average molecular weight- The weight-average molecular weight of the sulfomethylated kraft lignin is preferably 5,000 or more, more preferably 5,500 or more. The upper limit is 37,000 or less, more preferably 36,000 or less, even more preferably 30,000 or less, and even more preferably 23,000 or less. Therefore, the weight-average molecular weight is preferably 5,000 to 37,000, more preferably 5,000 to 36,000, even more preferably 5,000 to 30,000, and even more preferably 5,000 to 23,000 or 5,500 to 23,000. When the weight-average molecular weight of the sulfomethylated kraft lignin satisfies the above numerical range, an agricultural additive with excellent spreadability can be obtained.

[0015] -Polydispersity- The polydispersity (weight average molecular weight / number average molecular weight) of the sulfomethylated kraft lignin is preferably 1.5 or more, more preferably 1.6 or more. The upper limit is preferably 4.7 or less, more preferably 4.4 or less, and even more preferably 4.0 or less. Therefore, the polydispersity is preferably 1.5 to 4.7, more preferably 1.5 to 4.4, and even more preferably 1.6 to 4.0.

[0016] The weight-average molecular weight and number-average molecular weight of the sulfomethylated kraft lignin of the present invention can be measured by a conventional method. For example, a known method using gel permeation chromatography (GPC) in terms of pullulan can be used. More specifically, the measurement conditions can be used as described in the examples below.

[0017] -Total degradation product yield by alkaline nitrobenzene oxidation- The total yield of degradation products by alkaline nitrobenzene oxidation of sulfomethylated kraft lignin is preferably 14.5% or less, more preferably 14% or less, even more preferably 13.5% or less, and even more preferably 13.4% or less. The lower limit is preferably 3.5% or more, more preferably 4.0% or more. Therefore, the total yield of degradation products by alkaline nitrobenzene oxidation is preferably 14.5% or less, more preferably 14% or less, even more preferably 3.5 to 13.5%, and even more preferably 4.0 to 13.4%.

[0018] Measurement of the total degradation product yield by alkaline nitrobenzene oxidation is a method for measuring the yield of products (yield relative to the weight of sulfomethylated kraft lignin (solid content) before degradation) when lignin components are oxidatively decomposed with nitrobenzene under strong alkali, as in the method described in the Examples, and can be performed, for example, according to "Plant Cell Wall Experimental Methods" ("Plant Cell Wall Experimental Methods," pp. 128-131, 2016, Hirosaki University Press). Decomposition products include, for example, p-hydroxybenzaldehyde, p-hydroxybenzoic acid, vanillin, vanillic acid, syringaldehyde, and syringic acid.

[0019] [Method of producing sulfomethylated kraft lignin] Sulfomethylated kraft lignin can be obtained by sulfomethylating kraft lignin as a raw material.

[0020] -Kraft lignin- Kraft lignin is also called thiolignin or sulfate lignin. Kraft lignin may be isolated from the kraft pulp production process (e.g., the kraft cooking process) or may be a commercially available product. The raw material for kraft lignin may be either softwood (N-wood) or hardwood (L-wood), with N-wood being preferred. N-wood lignin is composed exclusively of guaiacyl lignin (G nucleus), in which the 5-position of the aromatic nucleus is unsubstituted, and tends to be easily sulfomethylated. Examples of lignin components containing kraft lignin isolated from raw materials include UF-treated kraft black liquor, an alkaline solution of kraft lignin, powdered kraft lignin obtained by spray-drying an alkaline solution of kraft lignin and powdering it, and acid-precipitated kraft lignin obtained by precipitating an alkaline solution of kraft lignin with an acid.

[0021] -Kraft cooking method- Kraft cooking is a cooking method in which chemicals containing caustic soda (NaOH) and sodium sulfide (NaS) as main components are added. In the kraft cooking method, the amount of caustic soda used is usually 1% by mass or more, preferably 10% by mass or more, based on the mass of bone-dry wood chips. The upper limit is usually 50% by mass or less, preferably 30% by mass or less. Therefore, it is usually 1 to 50% by mass, preferably 10 to 30% by mass. It is preferable that the amount of caustic soda used is within the above numerical range, because lignin can be sufficiently separated while maintaining the pulp yield and quality. In the kraft cooking method, the amount of sodium sulfide used is usually 1% by mass or more, preferably 2% by mass or more, more preferably 3% by mass or more. The upper limit is usually 30% by mass or less, preferably 20% by mass or less, more preferably 10% by mass or less. Therefore, it is usually 1 to 30% by mass, preferably 2 to 20% by mass, more preferably 3 to 10% by mass.

[0022] The cooking liquor may further contain a cooking aid. Examples of the cooking aid component include a cooking penetrant (e.g., quinones such as quinone compounds and hydroquinone compounds). Examples of quinones include anthraquinone, dihydroanthraquinone (e.g., 1,4-dihydroanthraquinone), tetrahydroanthraquinone (e.g., 1,4,4a,9a-tetrahydroanthraquinone, 1,2,3,4-tetrahydroanthraquinone), methylanthraquinone (e.g., 1-methylanthraquinone, 2-methylanthraquinone), methyldihydroanthraquinone (e.g., 2-methyl-1,4-dihydroanthraquinone), methyltetrahydroanthraquinone (e.g., 1-methyl-1,4,4a,9a-tetrahydroanthraquinone), Examples of quinones include tetrahydroanthraquinone, 2-methyl-1,4,4a,9a-tetrahydroanthraquinone, anthrahydroquinones (e.g., 9,10-dihydroxyanthracene), methylanthrahydroquinones (e.g., 2-methylanthrahydroquinone), dihydroanthradihydroxyquinones (e.g., 1,4-dihydro-9,10-dihydroxyanthracene), metal salts thereof (e.g., alkali metal salts such as sodium salts and disodium salts), and precursors of the above quinones (e.g., anthrone, anthranol, methylanthrone, methylanthranol). Note that quinone precursors may be converted into quinone compounds or hydroquinone compounds under cooking conditions. The quinones may be one type or a combination of two or more types. When quinones are contained, the amount added is preferably 0.01 to 5 mass% per bone-dry wood chip.

[0023] The cooking liquor can have an active alkali addition rate (AA) of 8 to 55% by mass, preferably 8 to 30% by mass or 8 to 20% by mass, based on the mass of bone-dry wood chips. An active alkali addition rate of 8% by mass or more can avoid insufficient removal of lignin and hemylulose, while an active alkali addition rate of 55% by mass or less can prevent a decrease in yield and suppress a decrease in quality. Here, the active alkali addition rate is the addition rate of NaOH and Na2S converted into the addition rate of Na2O, and can be converted to the addition rate of Na2O by multiplying the addition rate of NaOH by 0.775. The sulfidity is preferably in the range of 15 to 40%. In the sulfidity range of 15% or more, a decrease in delignification ability, a decrease in pulp viscosity, and an increase in the dregs ratio can be suppressed. By keeping the sulfidity at 40% or less, an effect commensurate with the amount added can be obtained.

[0024] The H factor (Hf) in cooking is preferably 250 to 2500, more preferably 400 to 2000, and even more preferably 600 to 1900. The H factor is an index representing the total amount of heat given to the reaction system during cooking, and is expressed by the following formula (1): Hf=∫exp(43.20-16113 / T)dt (1) In equation (1), T represents the absolute temperature at a certain point in time. The H factor is calculated by integrating the time from when the chips and water are mixed to when the cooking process is completed. The H factor can be used as an indicator to appropriately set the cooking temperature and cooking time.

[0025] Cooking may be carried out at a high temperature. The heating temperature is usually 120 to 180° C., preferably 140 to 180° C., and more preferably 150 to 170° C. The cooking time (the time from when the cooking temperature reaches the maximum temperature until the temperature starts to decrease) is usually 60 to 600 minutes, and preferably 120 to 360 minutes.

[0026] Cooking can be carried out using a vessel (for example, a pressure-resistant vessel such as an autoclave) that can accommodate wood chips and cooking liquor. The liquid ratio of wood chips to cooking liquor is usually 1.0 to 40 L / kg, preferably 1.5 to 30 L / kg, and more preferably 2.0 to 30 L / kg. Cooking types include, for example, a single-vessel liquid phase type, a single-vessel gas / liquid phase type, a double-vessel liquid / gas phase type, and a double-vessel liquid phase type, and any of these may be used.

[0027] Lignin can be obtained after the cooking process, for example, by separating it from cooking waste liquor (black liquor). Such a method is not particularly limited, and examples include filtration treatments such as UF treatment using an ultrafiltration membrane (UF membrane) and the Lignoboost (registered trademark) method (for example, the method described in JP-A-2008-513549), with the Lignoboost method being preferred. The Lignoboost method involves treating black liquor with carbon dioxide, filtering the resulting precipitate, dispersing it again in water, and adding acid to cause precipitation and dehydration. This method yields high-purity lignin.

[0028] The alkaline solution of kraft lignin can be obtained, for example, by the method described in JP 2000-336589 A, i.e., by electrolyzing an alkaline solution containing NaS flowing in a kraft pulp production process by electrolytic oxidation to produce an NaOH solution on the cathode side, but is not limited to these methods.

[0029] As the acid-precipitated kraft lignin obtained by precipitating an alkaline solution of kraft lignin with an acid, powdery acid-precipitated kraft lignin obtained by the methods described in WO 2006 / 038863, WO 2006 / 031175, and WO 2012 / 005677 can be used, but is not limited to these methods.

[0030] As the kraft lignin, one type of lignin may be used alone, or two or more types that differ in raw materials, production conditions, separation methods, etc. may be used in combination.

[0031] -Sulfomethylation- Sulfomethylation can be achieved, for example, by reacting kraft lignin with sulfite and aldehydes.

[0032] An example of a method for sulfomethylating a lignin component is disclosed in U.S. Patent No. 2,680,113. In this method, the sulfomethylation treatment of the lignin component is usually carried out at a temperature range of 50 to 200° C., preferably 80 to 170° C., and more preferably 90 to 170° C. The reaction time for the sulfomethylation treatment is preferably 1 to 30 hours, and more preferably 1.5 to 25 hours.

[0033] The sulfite is preferably sodium sulfite. The amount of sulfite added is preferably 1 to 50% by mass, more preferably 1 to 35% by mass, relative to 100% by mass of the solids content of the kraft lignin. By adding the sulfite in the above-mentioned range, the balance between the hydrophilicity and hydrophobicity of the lignin can be adjusted, and an agricultural additive with better spreadability can be obtained. Furthermore, by setting the upper limit of the amount of sulfite added in the above-mentioned range, the generation of unreacted substances such as sulfite can be suppressed, the purity of the lignin can be increased, and better spreadability can be achieved.

[0034] As the aldehyde, formaldehyde is preferred. The amount of aldehyde to be added is preferably 0.25 to 12.5 mass% and more preferably 0.3 to 10 mass% relative to 100 mass% of the solid content of the lignin component. By using an aldehyde in the above range, sulfo groups are suitably introduced into the lignin, resulting in an agricultural additive with better spreadability.

[0035] The pH is preferably 8 or higher, more preferably 9 or higher.

[0036] The weight-average molecular weight, organic S content, polydispersity index, and total yield of degradation products by alkaline nitrobenzene oxidation of sulfomethylated kraft lignin can be adjusted by the above-mentioned production conditions of sulfomethylated kraft lignin, specifically, by the raw material of kraft lignin (e.g., hardwood or softwood, tree species), the preparation method of kraft lignin (method of preparing kraft lignin from pulp), the preparation conditions of sulfomethylated kraft lignin (the amount of sulfite or aldehydes added, reaction temperature, reaction time, as described below), and oxidation treatment.

[0037] -Functional ingredients- In addition to sulfomethylated kraft lignin, agricultural chemical additives may contain functional ingredients. Examples of functional ingredients include active ingredients in pesticides and fertilizers. Examples of agricultural chemicals include herbicides, insecticides, miticides, nematicides, fungicides, bactericides, and other chemicals containing ingredients that can control or exterminate harmful organisms.

[0038] -Optional ingredients- The agricultural chemical additive may contain components (optional components) other than sulfomethylated kraft lignin, as needed. Examples of optional components include excipients, colorants, preservatives, pH adjusters, stabilizers, disintegrants, carriers, binders, pH adjusters, antifoaming agents, nonionic surfactants, cationic surfactants, and amphoteric surfactants (formulation aids). The amount of optional components used is usually 0 to 30% by mass relative to the sulfomethylated kraft lignin.

[0039] [Target for pesticide additives] The pesticide additive of the present invention exhibits spreadability due to the inclusion of the above-mentioned sulfomethylated kraft lignin, and thus, by incorporating it into a pesticide, functional components and the like in the pesticide can be dispersed in a dispersing medium. In this specification, spreadability refers to the property of a spreadable substance dispersing in water or on the water surface, spreading uniformly and quickly, and preferably over a wide area. Since the pesticide additive of the present invention exhibits spreadability for a spreadable substance (dispersed substance) when water is used as a dispersing medium, it is useful as a pesticide additive for paddy fields, hydroponics, and irrigation, more preferably for hydroponics or paddy fields. The dispersed substance to be spread by the pesticide additive is not particularly limited, and can be, for example, a component (usually a functional component, but not particularly limited to) in a pesticide to which the pesticide additive is added, such as the functional component or optional component described above.

[0040] [Form of pesticide additives] The dosage form of the pesticide additive is not particularly limited, and may be, for example, granular, particulate, or liquid. The pesticide additive may be formulated together with components constituting the pesticide, such as functional ingredients, or may be formulated separately. A suitable method for producing the pesticide additive can be selected as appropriate depending on the dosage form.

[0041] [2. Pesticides containing the pesticide additive of the present invention] [Functional ingredients and optional ingredients in pesticides] The functional ingredients and optional ingredients in the pesticide are not particularly limited, and are the same as those described in the "-Functional ingredients-" and "-Optional ingredients-" sections, for example.

[0042] [Pesticide formulation] The dosage form of the pesticide is not particularly limited, and examples thereof include granules, tablets (e.g., flat plates, granules), powders, and liquids (e.g., liquids, aqueous suspensions, aqueous dispersions, flowables, and emulsions). Granules and granules can facilitate application. Liquids can also facilitate mixing with functional ingredients, stabilizing the slurry after mixing. The pesticide additive of the present invention can be formulated together with functional ingredients to form a pesticide, or it can be formulated separately. An appropriate method for producing the pesticide can be selected according to the dosage form.

[0043] [3. How to use] The amount of the pesticide additive to be added to the pesticide may be an effective amount, for example, preferably 0.01 to 10% by mass, more preferably 0.1 to 8% by mass, and even more preferably 0.1 to 5% by mass, in terms of the amount of sulfomethylated kraft lignin relative to the target substance in the pesticide that the pesticide additive is intended to spread.

[0044] When the pesticide additive is a formulation separate from the functional ingredient, it may be blended directly with the other ingredients, or may be added after dissolving in water. For example, in the formulation of a pesticide, the agricultural additive may be added to the functional ingredient and optional ingredients described above to form a pesticide formulation (e.g., a tablet pesticide formulation), or when using the pesticide formulation, the pesticide formulation and the pesticide additive may both be dissolved in water and used. [Example]

[0045] The present invention will be described below with reference to examples, which are not intended to limit the scope of the present invention.

[0046] (Measurement and evaluation methods) In the examples and comparative examples, measurements and evaluations were carried out as follows.

[0047] (Measurement of weight average molecular weight and polydispersity (weight average molecular weight / number average molecular weight)) The weight-average molecular weight and number-average molecular weight of the lignin produced in each production example were measured by gel permeation chromatography (GPC) (Table 1). GPC measurements were performed using a known pullulan conversion method under the following conditions. The measured weight-average molecular weight and number-average molecular weight were used to calculate the polydispersity (weight-average molecular weight / number-average molecular weight) (Table 1). Measuring device: Tosoh Columns used: Shodex Column OH-pak SB-806HQ, SB-804HQ, SB-802.5HQ Eluent: 1.0% sodium tetraborate, 0.3% isopropyl alcohol aqueous solution Eluent flow rate; 1.00mL / min Column temperature: 50°C Measurement sample concentration: 0.2% by mass Standard substance: Pullulan (Showa Denko) Detector: RI detector (manufactured by Tosoh) Calibration curve; pullulan standard

[0048] (Organic S content) The organic S content of the lignin produced in each production example was calculated using the following formula. Organic S content (mass%) = total S content (mass%) - inorganic S content (mass%) (The S content in the formula indicates the S content relative to the solid content of the lignin sample.) In the formula, the total S content was determined by ICP atomic emission spectrometry. The inorganic S content was calculated using the sum of the SO3 ion content, SO4 ion content, and S2O3 ion content determined by ion chromatography (Table 1).

[0049] (Total degradation product yield by alkaline nitrobenzene oxidation) The total degradation product yield from alkaline nitrobenzene oxidation of the lignin produced in each production example was measured using the method described in "Plant Cell Wall Experimental Methods" (see "Plant Cell Wall Experimental Methods," pp. 128-131, 2016, Hirosaki University Press). The total degradation product yield was calculated as the ratio (w / w%) of the total weight of the six degradation products (p-hydroxybenzaldehyde, p-hydroxybenzoic acid, vanillin, vanillic acid, syringaldehyde, and syringic acid) to the solid content of the sample (Table 1).

[0050] (Production Example 1) (Production of sulfomethylated kraft lignin 1) Softwood (native) kraft lignin was isolated using a known method. Specifically, wood chips (Radiata pine) were first treated with alkali using the kraft cooking method. The alkali treatment was carried out using a rotary reactor under the following conditions: active alkali (relative to bone-dry chips): 20%, sulfidity: 25%, liquor ratio: 3.2 L / kg, reaction temperature: 165°C, and reaction time: 180 minutes. The reaction liquor used in the alkali treatment was prepared by dissolving sodium hydroxide and sodium sulfide in water to an active alkali concentration of 50 g / L. After the reaction, filtration was performed to obtain the filtrate from the native kraft cooking black liquor. Native kraft lignin was obtained from the native kraft cooking black liquor using the Lignoboost method. Specifically, carbon dioxide was first passed through the native kraft cooking black liquor to lower the pH to 10, and primary filtration was then performed. The kraft lignin was then dispersed in water again, the pH was lowered to 2 with sulfuric acid, and the secondary filtration was performed. The kraft lignin was then washed with water and dried to obtain the natural wood kraft lignin. All filtration processes were performed by pressure filtration using a filter press. Next, 500 parts of a solution of natural wood kraft lignin dissolved in NaOH at pH 10 to a solids content of 17% (26.0 parts of sodium sulfite, 18.1 parts of 37% formaldehyde solution) were added to a glass reaction vessel equipped with a thermometer, a stirrer, and a reflux condenser, and the mixture was reacted at 95°C for 24 hours with stirring. After cooling to room temperature, sulfomethylated kraft lignin 1 was obtained.

[0051] (Production Example 2) (Production of sulfomethylated kraft lignin 2) A glass reactor equipped with a thermometer, a stirrer, and a reflux condenser was charged with 500 parts of a solution prepared by dissolving the N-wood kraft lignin obtained in Production Example 1 in NaOH at pH 10 to a solids content of 17%, 17.0 parts of sodium sulfite, and 12.0 parts of a 37% formaldehyde solution, and the mixture was reacted at 95°C for 24 hours with stirring. After cooling to room temperature, sulfomethylated kraft lignin 2 was obtained.

[0052] (Production Example 3) (Production of sulfomethylated kraft lignin 3) A 1 L autoclave equipped with a thermometer, stirrer, and reflux condenser was charged with 500 parts of a solution of N-wood kraft lignin obtained in Production Example 1 dissolved in NaOH to a pH of 10 to a solids content of 17%, 17.0 parts of sodium sulfite, and 12.0 parts of a 37% formaldehyde solution, and the mixture was reacted at 140°C for 2 hours with stirring. After cooling to room temperature, sulfomethylated kraft lignin 3 was obtained.

[0053] (Production Example 4) (Production of sulfomethylated kraft lignin 4) A glass reactor equipped with a thermometer, a stirrer, and a reflux condenser was charged with 500 parts of a solution prepared by dissolving the N-wood kraft lignin obtained in Production Example 1 in NaOH at pH 10 to a solids content of 17%, 8.5 parts of sodium sulfite, and 6.0 parts of a 37% formaldehyde solution, and the mixture was reacted at 92°C for 18 hours with stirring. After cooling to room temperature, sulfomethylated kraft lignin 4 was obtained.

[0054] (Production Example 5) (Production of sulfomethylated kraft lignin 5) A 1-liter autoclave equipped with a thermometer, stirrer, and reflux condenser was charged with 500 parts of a solution prepared by dissolving the N-wood kraft lignin obtained in Production Example 1 in NaOH at pH 10 to a solids content of 17%, 4.3 parts of sodium sulfite, and 3.0 parts of a 37% formaldehyde solution, and the mixture was reacted at 160°C for 2 hours with stirring. After cooling to room temperature, sulfomethylated kraft lignin 5 was obtained.

[0055] (Production Example 6) (Production of sulfomethylated kraft lignin 6) A glass reactor equipped with a thermometer, a stirrer, and a reflux condenser was charged with 500 parts of a solution prepared by dissolving the N-wood kraft lignin obtained in Production Example 1 in NaOH at pH 10 to a solids content of 17%, 2.1 parts of sodium sulfite, and 1.5 parts of a 37% formaldehyde solution, and the mixture was reacted at 95°C for 24 hours with stirring. After cooling to room temperature, sulfomethylated kraft lignin 6 was obtained.

[0056] (Production Example 7) (Production of sulfomethylated kraft lignin 7) A glass reactor equipped with a thermometer, a stirrer, and a reflux condenser was charged with 500 parts of a solution prepared by dissolving the N-wood kraft lignin obtained in Production Example 1 in NaOH at pH 10 to a solids content of 17%, 2.1 parts of sodium sulfite, and 6.0 parts of a 37% formaldehyde solution, and the mixture was reacted at 95°C for 24 hours with stirring. After cooling to room temperature, sulfomethylated kraft lignin 7 was obtained.

[0057] (Production Example 8) (Production of sulfomethylated kraft lignin 8) A glass reactor equipped with a thermometer, a stirrer, and a reflux condenser was charged with 500 parts of a solution prepared by dissolving the N-wood kraft lignin obtained in Production Example 1 in NaOH at pH 10 to a solids content of 17%, 4.3 parts of sodium sulfite, and 6.0 parts of a 37% formaldehyde solution, and the mixture was reacted at 95°C for 24 hours with stirring. After cooling to room temperature, sulfomethylated kraft lignin 8 was obtained.

[0058] (Production Example 9) (Production of sulfomethylated kraft lignin 9) Hardwood (Large-leaved wood) kraft lignin was isolated using a known method. Specifically, wood chips (eucalyptus) were first treated with alkali using the Kraft cooking method. The alkali treatment was carried out using a rotary reactor under the following conditions: active alkali (relative to bone-dry chips): 20%, sulfidity: 25%, liquor ratio: 3.2 L / kg, reaction temperature: 155°C, and reaction time: 300 minutes. The reaction liquor used in the alkali treatment was prepared by dissolving sodium hydroxide and sodium sulfide in water to an active alkali concentration of 50 g / L. After the reaction, filtration was carried out to obtain L-wood kraft cooking black liquor as the filtrate. L-wood kraft lignin was obtained from the L-wood kraft cooking black liquor using the Lignoboost method. Specifically, carbon dioxide was first passed through the L-wood kraft cooking black liquor to lower the pH to 10, and primary filtration was then carried out. The kraft lignin was then dispersed in water again, the pH was lowered to 2 with sulfuric acid, and the secondary filtration was performed. The kraft lignin was then washed with water and dried to obtain kraft lignin. All filtration processes were performed using a filter press under pressure. Next, 500 parts of a solution of wood kraft lignin dissolved in NaOH at pH 10 to a solids content of 17% (17%), 17.0 parts of sodium sulfite, and 12.0 parts of a 37% formaldehyde solution were added to a glass reactor equipped with a thermometer, a stirrer, and a reflux condenser, and the mixture was reacted at 95°C for 24 hours with stirring. After cooling to room temperature, sulfomethylated kraft lignin 9 was obtained.

[0059] (Production Example 10) (Production of sulfomethylated kraft lignin 10) A glass reactor equipped with a thermometer, stirrer, and reflux condenser was charged with 500 parts of a solution prepared by dissolving the wood kraft lignin obtained in Production Example 9 in NaOH at pH 10 to a solids content of 17%, 2.1 parts of sodium sulfite, and 1.5 parts of a 37% formaldehyde solution, and the mixture was reacted at 96°C for 24 hours with stirring. After cooling to room temperature, sulfomethylated kraft lignin 10 was obtained.

[0060] (Production Example 11) (Production of sulfomethylated kraft lignin 11) A glass reactor equipped with a thermometer, a stirrer, and a reflux condenser was charged with 500 parts of a solution prepared by dissolving the wood kraft lignin obtained in Production Example 9 in NaOH at pH 10 to a solids content of 17%, 1.3 parts of sodium sulfite, and 0.9 parts of a 37% formaldehyde solution, and the mixture was reacted at 96°C for 24 hours with stirring. After cooling to room temperature, sulfomethylated kraft lignin 11 was obtained.

[0061] (Manufacturing Example 12) (Production of sulfomethylated kraft lignin 12) A glass reactor equipped with a thermometer, a stirrer, and a reflux condenser was charged with 500 parts of a solution prepared by dissolving the N-wood kraft lignin obtained in Production Example 1 in NaOH at pH 10 to a solids content of 15%, 3.8 parts of sodium sulfite, and 10.6 parts of a 37% formaldehyde solution, and the mixture was reacted at 95°C for 24 hours with stirring. After cooling to room temperature, sulfomethylated kraft lignin 12 was obtained.

[0062] (Manufacturing Example 13) (Production of lignosulfonates) Wood chips (radiata pine) were sulfite-treated using the sulfite cooking method. The sulfite treatment involved using a sodium sulfite solution with a SO2 concentration of 4 g / 100 mL at 140°C, pH 2, and a treatment time of 4 hours. The resulting intermediate composition was filtered and dehydrated to obtain a filtrate. The filtrate was concentrated using a rotary evaporator until the solids content reached 50%. The pH of the solution was then adjusted to 4.5 with NaOH and powdered using a spray dryer. The resulting powder was dissolved in water to prepare an aqueous solution with a solids content of 25%. This solution was then dialyzed for 3 days using a dialysis membrane (molecular weight cutoff: 20,000, Spectra / Por cellulose ester dialysis tubing). The solution in the dialysis tubing was collected, concentrated to 25% of the original volume, and powdered using a spray dryer to obtain lignin sulfonate.

[0063] (Manufacturing Example 14) (Production of modified lignosulfonate) A 3-L autoclave equipped with a stirrer and temperature controller was charged with 500 g of the lignin sulfonate obtained in Production Example 13, 75 g of sodium hydroxide, and 1,500 g of water. The mixture was heated to 140°C with stirring and maintained at this temperature for 2 hours. It was then cooled to 70°C, and air was blown into it at 500 mL / min for 3 hours. The resulting solution was powdered using a spray dryer to obtain a modified lignin sulfonate.

[0064] Example 1 (Water surface spreadability test) 0.1 g of calcium stearate was weighed using a precision balance and placed in a tablet press. The resulting pellets were compacted at 20 MPa for 1 minute to obtain a calcium stearate sheet (final weight: 0.09 ± 0.002 g). A 14 cm x 46 cm plastic container was filled with 200 mL of clean water (16°C). The prepared calcium stearate sheet was placed on the edge of the container. 20 μL of an aqueous solution of sulfomethylated kraft lignin 1 (1% by mass) obtained in Preparation Example 1 was then gently dropped 1 cm behind the calcium stearate sheet. The spread distance of the calcium stearate sheet above the water surface after 1 minute (the distance (cm) from the position of the sheet before the sample was dropped to the position of the sheet after the sample was dropped) was measured (Table 1).

[0065] Examples 2 to 11 A water surface spreadability test was carried out in the same manner as in Example 1, except that sulfomethylated kraft lignins 2 to 11 obtained in Production Examples 2 to 11 were used instead of sulfomethylated kraft lignin 1 obtained in Production Example 1 (Table 1).

[0066] (Comparative Example 1) A water surface spreadability test was carried out in the same manner as in Example 1, except that sulfomethylated kraft lignin 12 obtained in Production Example 12 was used instead of sulfomethylated kraft lignin 1 obtained in Production Example 1 (Table 1).

[0067] (Comparative Example 2) A water surface spreadability test was carried out in the same manner as in Example 1, except that the lignin sulfonate obtained in Production Example 13 was used instead of the sulfomethylated kraft lignin 1 obtained in Production Example 1 (Table 1).

[0068] (Comparative Example 3) A water surface spreadability test was carried out in the same manner as in Example 1, except that the modified lignin sulfonate obtained in Production Example 14 was used instead of the sulfomethylated kraft lignin 1 obtained in Production Example 1 (Table 1).

[0069] Comparative Example 4 A water surface spreadability test was performed in the same manner as in Example 1, except that N-wood kraft lignin obtained in the middle of Production Example 1 was used instead of the sulfomethylated kraft lignin 1 obtained in Production Example 1 (Table 1).

[0070] (Comparative Example 5) A water surface spreadability test was carried out in the same manner as in Example 1, except that the L-wood kraft lignin obtained in the middle of Production Example 9 was used instead of the sulfomethylated kraft lignin 1 obtained in Production Example 1 (Table 1).

[0071] (Reference example) A water surface spreadability test was carried out in the same manner as in Example 1, except that 20 μL of distilled water was used instead of the additive (Table 1).

[0072] [Table 1]

[0073] As shown in Table 1, the sulfomethylated kraft lignins of Examples 1 to 11, which had sulfo groups added by sulfomethylation and had weight-average molecular weights and organic sulfur contents within appropriate numerical ranges, exhibited long spreading distances and good spreadability compared to Comparative Example 1, which used high-molecular-weight sulfomethylated kraft lignin 12; Comparative Examples 2 and 3, which used lignosulfonates or modified products thereof; and Comparative Examples 4 and 5, which used untreated kraft lignin. Among these, the lignosulfonates or modified products thereof of Comparative Examples 2 and 3 exhibited a certain degree of spreadability, but the spreadability of the sulfomethylated kraft lignins of Examples 1 to 11 was even greater. Generally, lignosulfonates have sulfo groups attached to the side chains of the C6-C3 units of lignin, whereas sulfomethylated kraft lignin has sulfo groups attached to aromatic rings via methyl groups. Although it is unclear, it is speculated that the difference in the position of the sulfo groups introduced affects the difference in spreadability between sulfomethylated kraft lignin and lignosulfonates. From the above results, it was revealed that the agricultural chemical additive of the present invention can exhibit good spreadability.

Claims

1. An agricultural chemical additive comprising sulfomethylated kraft lignin having a weight-average molecular weight of 5,000 to 37,000 and an organic S content of 1.3 to 5.1 mass%.

2. 2. The agricultural chemical additive according to claim 1, wherein the yield of total degradation products by alkaline nitrobenzene oxidation of sulfomethylated kraft lignin is 14% or less.

3. The agricultural chemical additive according to claim 1 or 2, wherein the weight average molecular weight of the sulfomethylated kraft lignin is 5,000 to 23,000.

4. 3. The agricultural chemical additive according to claim 1, wherein the polydispersity of the sulfomethylated kraft lignin is 1.5 to 4.

7.

5. The pesticide additive according to claim 1 or 2, which is for use in solid pesticides.

6. The pesticide additive according to claim 1 or 2, which is for use in liquid pesticides.

7. The pesticide additive according to claim 1 or 2, which is for use in pesticides for paddy field or hydroponic cultivation.

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