Emulsion composition, and ink, paint, and pesticide formulation containing the same

Abstract

To provide an emulsion composition capable of providing a formulation in which a high-viscosity (poly)glycerin fatty acid ester is reduced in viscosity, the emulsion composition being uniform after preparation, maintaining low viscosity even after long-term storage, and having high storage stability.SOLUTION: An emulsion composition contains 10 wt.% to 60 wt.% of a (poly)glycerin fatty acid ester that is solid at 30°C or has a viscosity of 2 Pa s to 200 Pa s at 30°C and has an HLB of 5 or less, 0.01 wt.% to 10 wt.% of an anionic surfactant, and water, wherein the emulsion has its external phase consisting of water.SELECTED DRAWING: None

Description

[Technical Field]

[0001] The present invention relates to emulsion compositions and inks, paints, and agricultural chemical formulations using the same. [Background technology]

[0002] (Poly)glycerin fatty acid esters are used not only in the food and cosmetics industries but also in industrial applications, such as resin crystallization accelerators (Patent Document 1), resin antistatic agents (Patent Document 2), liquid cleaners (Patent Document 3), inks (Patent Document 4), surface tension reducers (Patent Document 5), and molding machine cleaners (Patent Document 6). Many (poly)glycerin fatty acid esters are highly viscous fluids, which can lead to issues such as poor handling when mixed with other materials, high supply loads on reactors and agitators, blocking, and difficulty in uniform addition. Similarly, emulsions containing high concentrations of (poly)glycerin fatty acid esters often become highly viscous liquids. Issues arising from high emulsion viscosity include, for example, in the field of O / W emulsion inks, where the emulsion thickens at low temperatures, adversely affecting ink properties, and increased load on pumps and other supply devices due to the need to supply highly viscous fluids, resulting in larger equipment and more complex mechanisms (Patent Document 7). In addition, not only in the field of inks, but also in the field of emulsifiers, dispersants, and surfactants, low viscosity is desirable for ease of use, and for example, in the field of liquid detergents, it is considered desirable for the viscosity to be less than 500 mPa·s when poured into a washing machine (Patent Document 8). Also, in the field of herbicidal solutions, in which (poly)glycerol fatty acid esters are used as nonionic surfactants, too high a viscosity of the solution is considered undesirable because it not only makes handling difficult during preparation of the herbicidal solution, but also reduces the spreadability and sprayability of the herbicidal solution due to poor wettability (Patent Document 9). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2007-246623 [Patent Document 2] Japanese Patent Application Laid-Open No. 2007-126500 [Patent Document 3] Japanese Patent Application Laid-Open No. 2003-313589 [Patent Document 4] Japanese Patent Application Laid-Open No. 2004-043473 [Patent Document 5] Japanese Patent Application Laid-Open No. 2013-087234 [Patent Document 6] Japanese Patent Publication No. 2023-090144 [Patent Document 7] Japanese Patent Application Publication No. 02-086667 [Patent Document 8] Japanese Patent Application Publication No. 2023-127572 [Patent Document 9] Japanese Patent Publication No. 2023-060948 Summary of the Invention [Problem to be solved by the invention]

[0004] The present invention aims to provide a preparation in which a high-viscosity (poly)glycerin fatty acid ester is reduced in viscosity, and to provide an emulsion composition which is uniform after preparation, maintains a low viscosity even after long-term storage, and has high storage stability. [Means for solving the problem]

[0005] As a result of extensive research, the inventors have discovered that the above-mentioned problems can be solved by providing an emulsion composition containing 10% by weight to 60% by weight of a (poly)glycerin fatty acid ester that is solid at 30°C or has a viscosity of 2 Pa·s to 200 Pa·s at 30°C and an HLB of 5 or less, 0.01% by weight to 10% by weight of an anionic surfactant, and water, wherein the outer phase of the emulsion is composed of water. [Effects of the Invention]

[0006] By preparing the emulsion composition of the present invention from a highly viscous (poly)glycerol fatty acid ester, the emulsion composition has excellent handling properties, appearance, and processability, making it easier to use in applications such as inks, paints, and agricultural chemical formulations. DETAILED DESCRIPTION OF THE INVENTION

[0007] The present invention will be described below based on the embodiments, but the scope of the present invention is not limited to these embodiments, and modifications made within the scope of the present invention also fall within the scope of the present invention. Note that the range "to" includes the upper and lower limits.

[0008] The (poly)glycerin fatty acid ester of the present invention refers to a glycerin fatty acid ester or a polyglycerin fatty acid ester. A (poly)glycerin fatty acid ester is a compound having a (poly)glycerin skeleton in which fatty acids are attached via ester bonds to some or all of the hydroxyl groups present in one (poly)glycerin molecule.

[0009] The (poly)glycerin constituting the (poly)glycerin fatty acid ester of the present invention is preferably a (poly)glycerin having an average degree of polymerization calculated from the hydroxyl value of 1 to 20, more preferably an average degree of polymerization of 2 to 15. Specific examples of (poly)glycerin include glycerin, diglycerin, triglycerin, tetraglycerin, hexaglycerin, and decaglycerin. Commercially available products include glycerin, diglycerin S, PGL-S, polyglycerin #310, polyglycerin #500, and polyglycerin #750 (all manufactured by Sakamoto Pharmaceutical Industry Co., Ltd.). Here, the average degree of polymerization is the average degree of polymerization (n) of the (poly)glycerin calculated from the hydroxyl value by end group analysis. Specifically, the average degree of polymerization is calculated from the following formulas (Formula 1) and (Formula 2). (Formula 1) Molecular weight=74n+18 (Equation 2) Hydroxyl value = 56110(n+2) / molecular weight The hydroxyl value in the above formula (2) is a numerical value that indicates the number of hydroxyl groups contained in (poly)glycerin, and refers to the number of milligrams of potassium hydroxide required to neutralize the acetic acid required to acetylate the free hydroxyl groups contained in 1 g of (poly)glycerin. The number of milligrams of potassium hydroxide is calculated in accordance with "Standard Test Methods for the Analysis of Fats, Oils and Related Materials, 2013 Edition, Established by the Japan Oil Chemists' Society," edited by the Japan Oil Chemists' Society.

[0010] The fatty acid constituting the (poly)glycerin fatty acid ester used in the present invention is not particularly limited, but is preferably at least one saturated or unsaturated fatty acid having 2 to 22 carbon atoms, whether linear or branched. Specific examples of fatty acids include acetic acid, propionic acid, butyric acid, caproic acid, caprylic acid, 2-ethylhexanoic acid, 3,5,5'-trimethylhexanoic acid, capric acid, lauric acid, myristic acid, palmitic acid, stearic acid, isostearic acid, oleic acid, behenic acid, erucic acid, ricinoleic acid, and condensates thereof. Ricinoleic acid, condensates thereof, stearic acid, oleic acid, isostearic acid, palmitic acid, myristic acid, lauric acid, and caprylic acid are preferred. The fatty acids used are not limited to these, and these may be used alone or in combination.

[0011] The HLB value described in this invention is an index showing the balance between hydrophilicity and lipophilicity, expressed as a value from 0 to 20, with the closer to 0 the lipophilicity is, and the closer to 20 the hydrophilicity is. Various calculation methods for the HLB value are known, and the values are listed in catalogs provided by manufacturers. In this specification, the HLB value is calculated using the Atlas method from the saponification value of the ester and the neutralization value of the fatty acid, and is calculated using the following formula (1). The saponification value and neutralization value in formula (1) are measured in accordance with "Standard Test Methods for the Analysis of Fats, Oils, and Related Materials, 2003 Edition, Established by the Japan Oil Chemists' Society," compiled by the Japan Oil Chemists' Society. HLB = 20 × (1 - saponification number / neutralization number) (1)

[0012] The (poly)glycerin fatty acid ester used in the present invention is characterized by being solid at 30°C or having a viscosity at 30°C of 2 Pa·s to 200 Pa·s, and an HLB of 5 or less. Specific examples of the (poly)glycerin fatty acid ester used in the present invention include glycerin caprylate, glycerin laurate, glycerin myristate, glycerin palmitate, glycerin stearate, glycerin oleate, glycerin isostearate, glycerin condensed ricinoleate, diglycerin caprylate, diglycerin laurate, diglycerin myristate, diglycerin palmitate, diglycerin stearate, diglycerin oleate, diglycerin isostearate, diglycerin condensed ricinoleate, triglycerin caprylate, triglycerin laurate, triglycerin myristate, triglycerin palmitate, triglycerin stearate, triglycerin oleate, triglycerin isostearate, triglycerin condensed ricinoleate, tetraglycerin caprylate, Examples of the glycerin esters include, but are not limited to, tetraglycerin laurate, tetraglycerin myristate, tetraglycerin palmitate, tetraglycerin stearate, tetraglycerin oleate, tetraglycerin isostearate, tetraglycerin condensed ricinoleate, hexaglycerin caprylate, hexaglycerin laurate, hexaglycerin myristate, hexaglycerin palmitate, hexaglycerin stearate, hexaglycerin oleate, hexaglycerin isostearate, hexaglycerin condensed ricinoleate, decaglycerin caprylate, decaglycerin laurate, decaglycerin myristate, decaglycerin palmitate, decaglycerin stearate, decaglycerin oleate, decaglycerin isostearate, and decaglycerin condensed ricinoleate. These glycerin esters may be used alone or in combination of two or more.

[0013] The proportion of the (poly)glycerin fatty acid ester blended in the emulsion composition of the present invention is 10% by weight to 60% by weight, preferably 30% by weight to 60% by weight, and more preferably 50% by weight to 60% by weight. By adjusting the blending proportion of the (poly)glycerin fatty acid ester to 10% by weight to 60% by weight, an emulsion with a uniform appearance can be obtained, and even systems that exhibit separation during long-term storage can be easily re-emulsified. Furthermore, by adjusting the blending proportion of the (poly)glycerin fatty acid ester to 30% by weight to 60% by weight, no separation is observed in appearance even after long-term storage.

[0014] The anionic surfactant to be incorporated into the emulsion composition of the present invention is appropriately selected depending on the application, and examples thereof include fatty acids or salts thereof, alkylbenzenesulfonic acids or salts thereof, alkyl sulfates or salts thereof, alkyl ether sulfates or salts thereof, alkyl phosphoric acids or salts thereof, α-olefinsulfonic acids or salts thereof, alkanesulfonic acids or salts thereof, etc. Alkylbenzenesulfonic acids or salts thereof are preferred, and linear alkylbenzenesulfonic acids or salts thereof are more preferred, but the surfactant is not limited thereto.

[0015] The content of the anionic surfactant in the emulsion composition of the present invention is 0.01 to 10% by weight, preferably 0.1 to 5% by weight, and more preferably 1 to 5% by weight.

[0016] The emulsion composition of the present invention refers to an emulsion in which the dispersed phase and continuous phase are clearly defined, and the emulsion particles are preferably spherical in shape, but are not limited thereto.

[0017] The average particle size of the emulsion composition of the present invention is preferably 3 μm to 15 μm, more preferably 4 μm to 10 μm. By adjusting the average particle size within these ranges, an emulsion with low viscosity and good dispersion stability can be obtained.

[0018] The emulsion form of the emulsion composition of the present invention works well in an O / W or W / O / W aqueous emulsion in which the external phase is water, with a W / O / W emulsion composition being more preferred.

[0019] When the viscosity of the emulsion composition of the present invention at 25°C is 0.1 mPa·s to 500 mPa·s, it becomes easy to handle when adding it to a compounding container, mixing it with other materials, preparing it, etc., and when it is 0.1 mPa·s to 200 mPa·s, it is suitable for use in a spray form. Furthermore, it is preferable that the viscosity of the emulsion composition stably maintains the above viscosity range even when stored at room temperature or low temperature.

[0020] Methods for preparing the emulsion composition of the present invention include, but are not limited to, manual stirring, a magnetic stirrer, a precision emulsifying disperser, an ultrasonic homogenizer, a homogenizer, a rocking mill, a bead mill, a kneader, or a combination of these as needed, but preferably, a precision emulsifying disperser or an ultrasonic homogenizer is used, as these are more efficient because they apply a strong mechanical shear force.

[0021] The applications of the emulsion composition of the present invention include, but are not limited to, inks, paints, pesticide formulations, etc. It is particularly preferred to use it in water-based inks, paints, pesticides, etc. [Example]

[0022] The present invention will be described below with reference to examples, but the present invention is not limited to these examples.

[0023] Example 1 To a 300 mL beaker, 2.5 g of anionic surfactant sodium alkylbenzene sulfonate aqueous solution (product name: Neopelex G-15, Kao, containing 16% alkylbenzene sulfonate as the active ingredient), 177.5 g of ion-exchanged water, and 20.0 g of CRS-75, a polyglycerol condensed ricinoleate, were added in this order. This mixture was stirred at 6000 RPM for 10 minutes using a precision emulsifying and dispersing machine, Clearmix (M-technique), to obtain an emulsion composition with a water-based outer phase. The viscosity of the raw material, CRS-75, at 30°C was 4610 mPa·s and its HLB was 3.3.

[0024] <Examples 2 to 7> An emulsion composition was obtained in the same manner as in Example 1, except that the blending amounts of Neopelex G-15, water, and CRS-75 were changed.

[0025] <Comparative Examples 1 to 3> An emulsion composition was obtained in the same manner as in Example 1, except that Neopelex G-15 was not added and the amount of water added was changed.

[0026] <Comparative Example 4> An emulsion composition was obtained in the same manner as in Example 2, except that CRS-75 was replaced with decaglycerol monostearate. Decaglycerol monostearate is solid at 30°C and has an HLB value of 14.1.

[0027] Examples 1 to 7 and Comparative Examples 1 to 4 were evaluated for appearance and viscosity.

[0028] <Viscosity> The emulsion compositions obtained in Examples 1 to 7 and Comparative Examples 1 to 4 were each placed in a 10 mL dedicated disposable cup, and the viscosity at 25°C was measured using a tuning fork vibro viscometer SV-100 (manufactured by A&D Co., Ltd.). The viscosity measurements were carried out immediately after the preparation of the emulsion compositions and one month after preparation. The viscosity evaluation results are shown in Table 1.

[0029] <Particle size> The emulsion compositions obtained in Examples 1 to 7 and Comparative Examples 1 to 4 were each attached to a slide glass, and a cover glass was placed over them to observe them under a fluorescence microscope BZ-810 (manufactured by Keyence). The particle shape and particle size of the emulsion were evaluated from the obtained microscopic images. The particle shape of the emulsion was judged based on the following evaluation criteria. Note that emulsions in which the liquid was in a mixed state and the dispersed and continuous phases of the emulsion could not be clearly distinguished were judged to be "impossible to measure." The particle evaluation results are shown in Table 1. Evaluation criteria Spherical: The diameter of the emulsion as seen in a microscopic image is 2 μm or more, and the shape is perfectly round. Amorphous: An emulsion in which the dispersed and continuous phases are clearly visible in a microscopic image and the shape is not circular. Miscible: The dispersed and continuous phases of an emulsion cannot be clearly distinguished from one another in a microscopic image.

[0030] <Appearance> The emulsion compositions obtained in Examples 1 to 7 and Comparative Examples 1 to 4 were filled into 30 mL glass containers, and the appearance was evaluated immediately after preparation and one month after preparation based on the following evaluation criteria. The appearance was evaluated immediately after preparation of the emulsion compositions and one month after preparation. The results of the appearance evaluation are shown in Table 1. Evaluation criteria Uniform: When filled into a transparent glass container and left to stand, the appearance is uniform and no concentration gradient is discernible. Separation: When filled into a transparent glass container and left to stand, the liquid appears to have dark and light areas.

[0031] [Table 1]

[0032] As can be seen from Table 1, the emulsion compositions shown in Examples 1 and 2 were emulsion compositions in which the viscosity of a high-viscosity polyglycerol fatty acid ester was reduced, and maintained a viscosity of 5 mPa·s or less even after one month at 25°C. Although separation occurred in appearance after one month, re-emulsification was easily possible by stirring the contents. On the other hand, in Comparative Example 1, although a low-viscosity composition was obtained, the particle shape was in a mixed state, and emulsion formation was not confirmed. Furthermore, separation was confirmed in appearance immediately after preparation, and emulsification was not possible even after one month had passed. Furthermore, the emulsion compositions shown in Examples 3 to 7, despite containing 50% by weight or more of a high-viscosity polyglycerol fatty acid ester, exhibited viscosities of 200 mPa·s or less, and maintained this low viscosity even after one month at 25°C or 5°C. Regarding appearance, even after one month, no separation or aggregation occurred, and the system remained homogeneous. On the other hand, in Comparative Examples 2 and 3, which did not contain an anionic surfactant, the viscosity after one month of storage at 25°C and 5°C was significantly higher at 500 mPa·s or more, and was inferior to the emulsion compositions shown in Examples 3 to 7 in terms of low viscosity. When a polyglycerol fatty acid ester with a high HLB was used as in Comparative Example 4, a composition with a low viscosity was obtained, but the particle shape was in a mixed state and the formation of an emulsion could not be confirmed.

Claims

1. An emulsion composition comprising 10% by weight to 60% by weight of a (poly)glycerin fatty acid ester that is solid at 30°C or has a viscosity of 2 Pa s to 200 Pa s at 30°C and an HLB of 5 or less, 0.01% by weight to 10% by weight of an anionic surfactant, and water, An emulsion composition wherein the external phase of the emulsion consists of water.

2. 2. The emulsion composition according to claim 1, wherein the structural moiety derived from a fatty acid of the (poly)glycerin fatty acid ester is at least one selected from the group consisting of ricinoleic acid, ricinoleic acid condensates, stearic acid, oleic acid, isostearic acid, palmitic acid, myristic acid, lauric acid, and caprylic acid.

3. 3. The emulsion composition according to claim 1, wherein the emulsion is composed of spherical particles having an average particle size of 3 μm to 15 μm.

4. Inks and paints containing the emulsion composition of claim 1.

5. A pesticide formulation comprising the emulsion composition of claim 1.

6. 2. The emulsion composition according to claim 1, which is used in the form of a spray.

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