Insulating varnish composition for motor impregnation and method for producing same
Patent Information
- Authority / Receiving Office
- WO · WO
- Patent Type
- Applications
- Current Assignee / Owner
- RYODEN KASEI
- Filing Date
- 2025-01-23
- Publication Date
- 2026-07-30
Smart Images
Figure JP2025002048_30072026_PF_FP_ABST
Abstract
Description
Insulating varnish composition for motor impregnation and method for producing the same
[0001] The present disclosure relates to an insulating varnish composition for motor impregnation and a method for producing the same.
[0002] For insulating varnishes used for motor coil insulation, high insulation performance and impregnability to be impregnated between narrow coil windings are required. Therefore, solvent-based varnishes in which a resin is dissolved in an organic solvent have conventionally been used. However, since solvent-based varnishes contain a large amount of volatile organic compounds (VOCs: Volatile Organic Compounds), they are not preferable from the viewpoints of the global environment and the influence on living things. Therefore, for example, techniques for reducing VOCs using high-boiling organic solvents as shown in Patent Document 1 have been studied. Further, Patent Document 2 discloses an emulsion-type varnish using water containing no VOC as a solvent.
[0003] Japanese Patent Application Laid-Open No. 2010-108820, US Patent No. 10340055
[0004] However, in the conventional technique using a high-boiling organic solvent, the viscosity of the insulating varnish becomes high at room temperature, so there is a problem that it is difficult to impregnate between narrow coil windings. Further, although using water as a solvent can reduce VOCs, there is a problem that the impregnability of impregnating the insulating varnish using capillary action between narrow coil windings decreases due to the high surface tension of water.
[0005] The present disclosure has been made to solve the above problems, and an object thereof is to provide an insulating varnish composition for motor impregnation using an aqueous solution with improved wettability as a solvent. Another object is to provide a method for producing an insulating varnish composition for motor impregnation.
[0006] The insulating varnish composition for motor impregnation according to the present disclosure includes micelles in which a thermosetting resin as a hydrophobic component and a curing agent that initiates the curing reaction of the thermosetting resin are incorporated inside an O / W emulsion having a hydrophilic component as a dispersion medium and a hydrophobic component as a dispersed substance, and a wettability improver that is not incorporated inside the micelles and is dispersed in the O / W emulsion.
[0007] Furthermore, the method for producing the insulating varnish composition for motor impregnation according to this disclosure comprises the steps of: preparing a mixture of a thermosetting resin and a curing agent; dispersing the mixture in an aqueous solution with a dispersant consisting of a surfactant to produce a W / O emulsion in which the hydrophobic component is the dispersion medium and the hydrophilic component is the dispersed phase; inverting the W / O emulsion into an O / W emulsion in which the hydrophilic component is the dispersion medium and the hydrophobic component is the dispersed phase; and adding a wettability improver to the phase-inverted O / W emulsion.
[0008] According to this disclosure, VOCs can be reduced, and because a sufficient amount of wettability improver is not incorporated into micelles but dispersed in the O / W emulsion, it can penetrate well into the narrow gaps between coil windings during motor impregnation, resulting in good impregnation properties.
[0009] This is an image diagram showing the schematic configuration of the motor impregnation insulating varnish composition according to Embodiment 1. This is an image diagram showing an example of the function of the motor impregnation insulating varnish composition according to Embodiment 1. This is a flowchart showing the manufacturing process of the motor impregnation insulating varnish composition according to Embodiment 1. This is a comparative diagram for explaining the motor impregnation insulating varnish composition according to Embodiment 1. This is a flowchart showing an example of the manufacturing process of the motor impregnation insulating varnish composition according to Embodiment 2. This is an image diagram showing the schematic of the manufacturing process of the motor impregnation insulating varnish composition according to Embodiment 2.
[0010] Embodiments will be described with reference to the drawings. Here, the same parts and corresponding components are denoted by the same reference numerals, and their detailed descriptions are omitted.
[0011] Embodiment 1. Figure 1 is an image diagram showing the schematic configuration of the motor impregnation insulating varnish composition 100 according to Embodiment 1. The motor impregnation insulating varnish composition 100 comprises an O / W (Oil-in-Water) emulsion 1 in which a hydrophilic component is dispersed medium 31 and a hydrophobic component is dispersed phase 21, and micelles 4 in which a thermosetting resin 2 and a curing agent 3 that initiates the curing reaction of the thermosetting resin 2 are incorporated as hydrophobic components, and a wettability improver 5 that is not incorporated into the micelles 4 but is dispersed in the O / W emulsion 1.
[0012] When an aqueous solution 6 and varnish components such as a thermosetting resin 2 and a curing agent 3 are mixed using a dispersant 7, the varnish components are dispersed or emulsified in the aqueous solution 6, but the surface tension of the aqueous solution 6, which is the dispersion medium 30, remains high. Therefore, when impregnating the motor coil 80 with varnish using methods such as the drop-impregnation method or the inversion-dip method, the varnish has poor wettability with respect to the coil 80, the enamel wire covering the coil winding 81, etc., impregnation takes a long time, and the adhesive strength after the varnish hardens is reduced. As a result of diligent research, the inventors have realized the motor impregnation insulating varnish composition 100 of this disclosure.
[0013] The motor impregnation insulating varnish composition 100 is formed by dispersing a thermosetting resin 2, such as epoxy resin, and a curing agent 3, such as organic peroxide, in an aqueous solution 6, such as water or aqueous ammonia, using a dispersant 7, such as a nonionic surfactant, to form micelles 4 as liquid colloids. As shown in Figure 1, the thermosetting resin 2 and curing agent 3 are incorporated into these micelles 4. In this state, phase inversion emulsification is performed to make them present in an O / W emulsion 1. The wettability improver 5 is not incorporated into the micelles 4 but exists in the hydrophilic component dispersion medium 31. Furthermore, if the wettability improver 5 has hydrophilic groups 51 and hydrophobic groups 52, it dissolves in the dispersion medium 31 and improves the impregnation properties in order to lower the viscosity of the motor impregnation insulating varnish composition 100. As shown in Figure 2, because the wettability improver 5 is not incorporated into the micelles 4 but exists in the hydrophilic component dispersion medium 31, this motor impregnation insulating varnish composition 100 has good penetration properties for enamel wires, etc., that cover the coil windings 81. Furthermore, because the wettability enhancer 5 is not incorporated into the micelles 4, it can lower the surface tension of the aqueous solution 6. As a result, it can penetrate between the narrow coil windings 81 using capillary action, resulting in an insulating varnish with good impregnation properties. The wettability enhancer 5 in the motor impregnation insulating varnish composition 100 will function even if only a small portion of it is incorporated into the micelles 4. It is sufficient if 50% or more, preferably 80% or more, of the added wettability enhancer 5 is not incorporated into the micelles 4.
[0014] Here, the wettability enhancer 5 can reduce the surface tension of the aqueous solution 6 because the surfactant preferentially adsorbs at the interface between the solid adherend, such as polyamide-imide resin or polyurethane resin (an enamel wire coating material), and the liquid varnish, thereby reducing intermolecular forces.
[0015] The wettability enhancer 5 may be, for example, an ether-based surfactant having hydrophobic reactive groups. Ether-based surfactants having hydrophobic reactive groups possess heat resistance, insulating properties, and chemical stability. Furthermore, it is preferable that the wettability enhancer 5 is composed of at least one of the copolymer represented by the following chemical formula (1) and the ether-based surfactant having hydrophobic reactive groups represented by the following chemical formula (2). Here, the arrangement of EO and PO may be in a block or random.
[0016]
[0017]
[0018] By configuring the wettability enhancer 5 in this manner, the surface tension of aqueous solution 6 such as water can be reduced through the action of the hydrophilic EO group, hydrogen group (-H), glycerol group (-O-C(CH2OH)2) in chemical formula (1), the glycerol group (-(O-C(CH2OH)2)) in chemical formula (2), and quaternary ammonium salt. Although the wettability enhancer 5 may remain in the cured product, the action of acrylates, methacrylates, etc. can ensure heat resistance, mechanical strength, insulation, water resistance, chemical resistance, flexibility, etc. Furthermore, since the functional group R1 does not cause aggregation with the thermosetting resin 2 due to intermolecular forces, the increase in viscosity of the emulsion itself is suppressed, and a low-viscosity emulsion can be obtained.
[0019] Furthermore, it is preferable that the wettability enhancer 5 is present in an amount of 0.1% by mass or more and 15% by mass or less relative to the entire composition containing the thermosetting resin 2, curing agent 3, dispersant 7, aqueous solution 6, and wettability enhancer 5. This is because if it is less than 0.1% by mass, it is difficult to achieve the desired wettability, and if it exceeds 15% by mass, it increases the viscosity.
[0020] In the micelle 4, hydrophobic components such as the thermosetting resin 2 and curing agent 3 are arranged facing inward, while the dispersant 7 is arranged on the outside, i.e., on the dispersion medium 31 side. The average particle size of the micelle 4 is preferably 0.1 μm or more and 0.5 μm or less. If it is less than 0.1 μm, it is easy to emulsify, making it difficult for the water component to evaporate during curing, and there is a risk that the water component will remain in the cured product. If it exceeds 0.5 μm, although the water component evaporates easily during curing, insufficient emulsification makes it easy for the hydrophobic and hydrophilic components to separate.
[0021] The dispersant 7 preferably contains a nonionic surfactant in an amount of 0.1% to 10% by mass relative to the entire composition, which includes the thermosetting resin 2, curing agent 3, dispersant 7, aqueous solution 6, and wettability enhancer 5. If the amount is less than 0.1% by mass, the hydrophobic and hydrophilic components are likely to separate due to insufficient emulsification. If it exceeds 10% by mass, the dispersant 7 may remain in the cured product, potentially leading to poor curing. A nonionic surfactant is used because it is preferable not to react with metal ions. For example, when impregnating a motor, coil 80, etc., with the motor impregnation insulating varnish composition 100, if the dispersant 7 is an ionic surfactant, metal ions generated from metals such as iron, which are materials for the motor, coil 80, etc., may impair the emulsification of the emulsion. This can sometimes be avoided by diluting with hard water, but it is preferable to use a nonionic surfactant.
[0022] The thermosetting resin 2 is preferably present in an amount of 5% to 60% by mass relative to the entire composition containing the thermosetting resin 2, curing agent 3, dispersant 7, aqueous solution 6, and wettability improver 5. It is even more preferable if it is 20% to 60% by mass. If it is less than 5% by mass, the adhesion amount, film thickness, etc. of the varnish composition may not be secured. If the adhesion amount, film thickness, etc., cannot be secured, the varnish may lack the necessary properties such as heat resistance, mechanical strength, and insulation. Also, if it exceeds 60% by mass, the viscosity of the insulating varnish composition may increase, potentially worsening its impregnation properties.
[0023] The insulating varnish composition 100 for motor impregnation can be obtained, for example, by the process shown in Figure 3. That is, a mixture of thermosetting resin 2 and curing agent 3 is prepared (step S101). Then, the mixture of thermosetting resin 2 and curing agent 3 is dispersed in an aqueous solution 6 with a dispersant 7 consisting of a surfactant to produce a W / O (Water-in-Oil) emulsion 12 in which the hydrophobic component is the dispersion medium 32 and the hydrophilic component is the dispersed phase 22 (step S102). Then, the W / O emulsion 12 is phase-inverted emulsified into an O / W emulsion 1 in which the hydrophilic component is the dispersion medium 31 and the hydrophobic component is the dispersed phase 21 (step S103). Then, a wettability improver 5 is added to the phase-inverted O / W emulsion 1 (step S104).
[0024] Even if the thermosetting resin 2 and curing agent 3 are added to the aqueous solution 6 and stirred, the thermosetting resin 2 is hydrophobic and will separate again over time. Therefore, micelles 4 are formed as liquid colloids using the dispersant 7 and dispersed in the aqueous solution 6 to produce a W / O emulsion 12 in which hydrophilic components are dispersed among hydrophobic components. Furthermore, the continuous phase of hydrophilic and hydrophobic components is inverted from the hydrophobic component to the hydrophilic component to produce an O / W emulsion 1. This stabilizes the emulsified state. When the thermosetting resin 2, curing agent 3, and wettability improver 5 are dispersed during the production of the O / W emulsion 1, for example, as shown in Figure 4, the thermosetting resin 2, curing agent 3, and wettability improver 5 are incorporated into the micelles 41 as dispersed phase 22. If this state is maintained, the wettability function of the wettability improver 5 cannot be fully exhibited when impregnating the motor impregnation insulating varnish composition 100 between coil windings 81, etc. Therefore, first, the thermosetting resin 2 and curing agent 3 are incorporated into the micelles 4 to generate an O / W emulsion 1. While the thermosetting resin 2 and curing agent 3 remain incorporated into the micelles 4, the wettability enhancer 5 is added and dispersed in the O / W emulsion 1. As a result, the wettability enhancer 5 is not incorporated into the micelles 4, and a varnish dispersed in the O / W emulsion 1 can be produced. When this motor impregnation insulating varnish composition 100 is impregnated between the coil windings 81, the wettability function of the dispersed wettability enhancer 5 is immediately exerted, improving impregnation. Furthermore, if the wettability enhancer 5 is made hydrophilic and hydrophobic, it can be easily dissolved in the O / W emulsion 1 by stirring or the like.
[0025] Here, whether or not phase inversion emulsification has occurred in the O / W emulsion 1 can be determined, for example, by whether or not the diameter of the micelles 41 in the emulsion has reached a set target value. For example, if the average micelle diameter is 0.3 μm or less, which is the set target value, it is determined that phase inversion emulsification has occurred. The set target value can be set as appropriate, for example, to be between 0.25 μm and 0.3 μm. Alternatively, it may be determined by the viscosity of the emulsion. In this case, the set target value may be, for example, to be around 50 Pa·s. Viscosity can be measured using, for example, an E-type viscometer. If the process is repeated under the same conditions, the empirical stirring time may be used as the set target value. This determination is made in the intermediate inspection, and after the set target value is reached, the wettability improver 5 may be added. Alternatively, after the intermediate inspection, phase inversion emulsification may be confirmed, and the wettability improver 5 may be added in the final step after sufficient stirring. It is preferable that not all of the wettability enhancer 5 added here is incorporated into the micelles 4 of the O / W emulsion 1. However, if 50% or more, preferably 80% or more of the added amount is not incorporated into the micelles 4 of the O / W emulsion 1 and is dispersed in the O / W emulsion 1, sufficient wettability can be achieved in impregnation between the coil windings 81.
[0026] The insulating varnish composition 100 for motor impregnation manufactured in this manner can have a viscosity of 500 mPa·s or less at 25°C, while ensuring the necessary amounts of thermosetting resin 2, curing agent 3, and wettability improver 5 for impregnation between coil windings 81. Lowering the viscosity to 500 mPa·s or less reduces shear force due to stirring, making it easier to disperse the added wettability improver 5 in the O / W emulsion 1. If the viscosity is 1 mPa·s or higher, it can be retained with less dripping between the coil windings 81.
[0027] The dispersant 7 is preferably a nonionic surfactant. This can improve the hydrophilic-hydrophobic balance (HLB value). Furthermore, when the motor, coil 80, etc. are immersed in the motor impregnation insulating varnish composition 100 to impregnate them, metal ions are not generated.
[0028] While the example shown uses water as the aqueous solution, other types of water may be used, such as deionized water or distilled water. Ammonia water or phosphoric acid solution may also be used.
[0029] Furthermore, the thermosetting resin 2 may be a modified epoxy resin such as epoxy acrylate resin. It may also be a urethane-modified resin modified with acrylic acid, an amine-modified resin, a fatty acid-modified resin, etc. Alternatively, an unmodified epoxy resin may be used. Examples of unmodified epoxy resins include compounds having a skeleton of bisphenol A type, bisphenol E type, bisphenol F type, hydrogenated phthalate type, cresol novolac type, phenol novolac type, resorcinol type, or tecmore-type polyphenylene ether type. In particular, bisphenol A epoxy resin and bisphenol F epoxy resin can contain or be mixed with a curing agent 3 such as alkyl glycidyl ether or glycidyl ester, and have a high emulsifying effect. Imide resins, amide-imide resins, etc., may also be used.
[0030] Although organic peroxides were given as examples of curing agent 3, other organic peroxides that can be used include perhexyl peroxides such as t-hexyl hydroperoxide, acyl peroxides such as benzoyl peroxide, peracid esters such as t-butyl peroxybenzoate, organic hydroperoxides such as tetramethylbutyl hydroperoxide, and dialkyl peroxides such as dicumyl peroxide. Furthermore, phenol compounds, acid anhydrides, amine compounds, etc., can be used as curing agent 3 for unmodified epoxy resin. Curing agent 3 is used to cure the thermosetting resin 2 and includes, for example, a reaction initiator for polymerization by radical polymerization.
[0031] While nonionic surfactants are given as examples of dispersant 7, examples of nonionic surfactants that can be used include polyoxyethylene alkyl ethers, polyoxyalkylene derivatives, sorbitan fatty acid esters, polyoxyethylene sorbitan fatty acid esters, polyoxyethylene sorbitol fatty acid esters, glycerin fatty acid esters, polyoxyethylene fatty acid esters, polyoxyethylene hydrogenated castor oil, polyoxyethylene alkylamines, alkyl alkanolamides, etc. When epoxy resin is used as thermosetting resin 2, polyoxyethylene alkyl ether, which has good compatibility with epoxy resin, is preferred. Although the use of nonionic surfactants is preferable, ionic surfactants may also be used when used in an environment that does not generate metal ions.
[0032] Furthermore, when curing the motor impregnation insulating varnish composition 100, the moisture is removed by a drying process, and then it is heated at a temperature of 130°C to 180°C for about 0.5 to 5 hours. The heating promotes the curing reaction of the thermosetting resin 2 of the motor impregnation insulating varnish composition 100 that has been impregnated on the surface of the coil 80 and between the coil windings 81, making it possible to obtain an insulating coil with excellent electrical and mechanical properties.
[0033] Thus, a motor impregnation insulating varnish composition 100 can be produced by the steps of: preparing a mixture of thermosetting resin 2 and curing agent 3; dispersing the mixture in an aqueous solution 6 with a dispersant 7 made of a surfactant to produce a W / O emulsion 12 in which the hydrophobic component is a dispersion medium 32 and the hydrophilic component is a dispersed phase 22; inverting the W / O emulsion 12 into an O / W emulsion 1 in which the hydrophilic component is a dispersion medium 31 and the hydrophobic component is a dispersed phase 21; and adding a wettability improver 5 to the phase-inverted O / W emulsion 1. This motor impregnation insulating varnish composition 100 can reduce VOCs, and because a sufficient amount of wettability improver 5 is not incorporated into the micelles 4 but dispersed in the O / W emulsion 1, it can penetrate well into the narrow gaps between the coil windings 81 during motor impregnation, providing good impregnation properties.
[0034] Furthermore, by configuring the wettability enhancer 5 with at least one of a copolymer represented by chemical formula (1) and an ether-based surfactant having a hydrophobic reactive group represented by chemical formula (2), it is possible to reduce the surface tension of the aqueous solution 6 such as water, which is the dispersion medium 31, and to create a low-viscosity emulsion that has the effect of improving heat resistance, mechanical strength, etc.
[0035] Embodiment 2. Embodiment 2 describes an example in which two or more dispersants 7 with different activity energies are used. For example, a nonionic surfactant that is solid at room temperature is used as the first dispersant 71, and a nonionic surfactant that is liquid at room temperature is used as the second dispersant 72. The rest is the same as in Embodiment 1.
[0036] Figure 5 is a flowchart showing an example of the manufacturing process for the insulating varnish composition 100 for motor impregnation according to Embodiment 2. First, a mixture of thermosetting resin 2 and curing agent 3 is prepared (step S201). Then, the mixture of thermosetting resin 2 and curing agent 3 and the first dispersant 71 are put into a tank 200 (step S202). By first dispersing the mixture with the first dispersant 71, the thermosetting resin 2 and curing agent 3 can be uniformly incorporated into the micelles 4. Then, the second dispersant 72 and deionized water are added to the tank 200 (step S203), and phase inversion emulsification is carried out while stirring (step S204). Then, it is determined whether or not phase inversion emulsification has occurred in the O / W emulsion 1 by whether or not the diameter of the micelles 4 has become less than or equal to the set target value (step S205). If the diameter of the micelles 4 is not less than or equal to the set target value (NO in step S205), stirring is continued to advance phase inversion emulsification. If the diameter of the micelles 4 is less than or equal to the set target value (YES in step S205), a wettability enhancer 5 having hydrophilic and hydrophobic properties is added to the tank 200 (step S206). Then, it is diluted and stirred to disperse the wettability enhancer 5 in the O / W emulsion 1 (step S207), and it is checked for any undissolved particles (step S208). If there are undissolved particles (NO in step S208), the process returns to step S207, where it is further diluted and stirred. If there are no undissolved particles (YES in step S208), the process is terminated.
[0037] More specifically, in step S201, where a mixture of thermosetting resin 2 and curing agent 3 is prepared, the mixture is heated to approximately 40-60°C. It is also preferable to heat the first dispersant 71 to approximately 40-60°C. Heating is performed when the thermosetting resin 2 is highly viscous or when the first dispersant 71 is solid. The mixture is heated so that it can be stirred after being added to the tank 200. It is also preferable to heat the mixture as needed to increase the activation energy of the first dispersant 71. After step S202, when the mixture of thermosetting resin 2 and curing agent 3 and the first dispersant 71 are added to the tank 200, the mixture is stirred continuously, and in this case, it is also preferable to heat it to approximately 40-60°C while stirring. After stirring for a certain period of time, in step S203, the second dispersant 72 and deionized water are added to the tank 200. The first dispersant 71 disperses the thermosetting resin 2 and curing agent 3, and for example, polyoxyethylene alkyl ether is used. The second dispersant 72 promotes the initiation of phase inversion emulsification, and for example, polyoxyethylene distyrenate phenyl ether is used. Then, the mixture is kneaded for about 1 to 2 hours while cooling the tank 200.
[0038] Here, a certain proportion of ion-exchanged water necessary for phase inversion is added, and phase inversion emulsification is promoted by applying shear force between, for example, an anchor-shaped stirring blade 201 attached in a U-shape to the stirring shaft and the wall of the tank 200. By balancing this shear force with the dispersion force of the second dispersant 72, the W / O emulsion 12 is converted to O / W emulsion 1. At this time, the second dispersant 72 chemically reduces the surface tension at the W / O interface, thereby reducing the load of physical forces such as stirrers and stabilizing phase inversion emulsification. Then, in step S205, it is determined whether the average micelle diameter has reached a set target value of, for example, 0.2 μm or less. The target set value can be set as appropriate. The average micelle diameter can be measured, for example, with a laser diffraction particle size distribution analyzer (LA-960S) manufactured by Horiba, Ltd. The determination in step S205 may be made based on set target values such as viscosity and stirring resistance value due to viscosity, in addition to the diameter of the micelles 41. In other words, when at least one of the micelle diameter, viscosity, and stirring resistance reaches a set target value, it can be determined that the mixture has undergone phase inversion emulsification into the O / W emulsion 1. Then, the addition of deionized water and stirring are continued until the set target value is reached, or for a certain period of time after the set target value is reached. In step S207, the wettability improver 5 is dispersed in the O / W emulsion 1 without being incorporated into the micelles 4, and stirring is continued until there are no undissolved particles. After the process is completed, the average micelle diameter, viscosity, pH, moisture content, etc., are inspected.
[0039] In this way, by using two or more surfactants with different activity energies as the dispersant 7, the first dispersant 71 disperses the thermosetting resin 2 and curing agent 3, and the second dispersant 72 forms micelles 4 in which the thermosetting resin 2 and curing agent 3 in the W / O emulsion 12 are arranged inward and dispersed in the O / W emulsion 1, each plays a role in dispersing the thermosetting resin 2 and promoting phase inversion emulsification, and the wettability improver 5 can be included in the motor impregnation insulating varnish composition 100 in an optimal state.
[0040] Although not described in Embodiments 1 and 2, reaction accelerators may be added as appropriate. For example, the curing temperature can be lowered by using accelerators such as cobalt, iron, or manganese derivatives. Amines, acetoacetates, amides, etc., may also be used in combination with metals. This promotes the decomposition of curing agents such as organic peroxides and generates radicals necessary for curing.
[0041] Specific examples of the present disclosure and the effects of the present disclosure compared with comparative examples will be described. Example 1. Under the conditions described in Embodiment 1, epoxy acrylate resin was prepared as the thermosetting resin 2, organic peroxide as the curing agent 3, a nonionic surfactant as the dispersant 7, and ion-exchanged water as the aqueous solution 6. The mixing ratios were 50% by mass, 0.5% by mass, 5% by mass, and 42.5% by mass, respectively, based on the total mass, and an O / W emulsion 1 was produced by phase inversion emulsification. After phase inversion emulsification, 2% by mass of the copolymer represented by chemical formula (1) was added as the wettability improver 5 and dispersed in the O / W emulsion 1 so as not to be incorporated into the micelles 4 in the O / W emulsion 1, thereby producing an insulating varnish composition 100 for motor impregnation.
[0042] Example 2. Similar to Example 1, a thermosetting resin 2, a curing agent 3, a dispersant 7, and an aqueous solution 6 were prepared under the conditions described in Embodiment 1, and an O / W emulsion 1 was produced by phase inversion emulsification. After phase inversion emulsification, 2% by mass of polyoxyethylene alkyl ether, a nonionic surfactant, was added as a wettability improver 5 and dispersed in the O / W emulsion 1 so as not to be incorporated into the micelles 4 in the O / W emulsion 1, thereby producing an insulating varnish composition 100 for motor impregnation.
[0043] Example 3. Under the conditions described in Embodiment 2, an epoxy acrylate resin was used as the thermosetting resin 2, an organic peroxide was used as the curing agent 3, a solid nonionic surfactant was used as the first dispersant 71, a liquid nonionic surfactant was used as the second dispersant 72, and ion-exchanged water was used as the aqueous solution 6. Each was prepared, and an O / W emulsion 1 was produced by phase inversion emulsification with the blending ratios being 50% by mass, 0.5% by mass, 2.5% by mass, 2.5% by mass, and 42.5% by mass, respectively, based on the total mass. After phase inversion emulsification, 2% by mass of the copolymer represented by Chemical Formula (1) was added as the wettability improver 5, and the wettability improver 5 was dispersed in the O / W emulsion 1 so as not to be incorporated into the micelles 4 in the O / W emulsion 1, thereby producing the insulating varnish composition 100 for motor impregnation.
[0044] Comparative Example 1. Under the conditions described in Embodiment 1, an epoxy acrylate resin was used as the thermosetting resin 2, an organic peroxide was used as the curing agent 3, a nonionic surfactant was used as the dispersant 7, ion-exchanged water was used as the aqueous solution 6, and polyoxyethylene alkyl ether, which is a nonionic surfactant, was used as the wettability improver 5. Each was prepared, and each material was added with the blending ratios being 50% by mass, 0.5% by mass, 5.0% by mass, 42.5% by mass, and 2% by mass, respectively, based on the total mass, thereby producing a comparative insulating varnish composition for motor impregnation. That is, a comparative insulating varnish composition for motor impregnation in which the wettability improver 5 was incorporated into the micelles 41 in the O / W emulsion 11 was produced.
[0045] Comparative Example 2. Under the conditions described in Embodiment 2, an epoxy acrylate resin was used as the thermosetting resin 2, an organic peroxide was used as the curing agent 3, a solid nonionic surfactant was used as the first dispersant 71, a liquid nonionic surfactant was used as the second dispersant 72, ion-exchanged water was used as the aqueous solution 6, and the copolymer represented by Chemical Formula (1) was used as the wettability improver 5. Each was prepared, and each material was added with the blending ratios being 50% by mass, 0.5% by mass, 2.5% by mass, 2.5% by mass, 42.5% by mass, and 2% by mass, respectively, based on the total mass, thereby producing a comparative insulating varnish composition for motor impregnation. That is, a comparative insulating varnish composition for motor impregnation in which the wettability improver 5 was incorporated into the micelles 41 in the O / W emulsion 11 was produced.
[0046] Table 1 shows a comparison table of Examples 1 to 3 and Comparative Examples 1 and 2.
[0047] The viscosity of the insulating varnish composition 100 for motor impregnation of Example 1 was 180 mPa·s, and the contact angle with the coil winding 81 after 30 seconds of impregnation into the coil 80 was 43°. The impregnation property was good. Since the wetting improver 5 was added after phase inversion emulsification, a sufficient amount of the wetting improver 5 was not incorporated into the micelles 4 but was dispersed in the O / W emulsion 1. Therefore, it could penetrate well into the narrow gaps between the coil windings 81 and had good impregnation properties. Also, by using the wetting improver 5 as a copolymer represented by Chemical Formula (1), the surface tension of the aqueous solution 6 which is the dispersion medium 31 could be decreased, and a low-viscosity emulsion could be obtained.
[0048] The viscosity of the insulating varnish composition 100 for motor impregnation of Example 2 was 250 mPa·s, and the contact angle with the coil winding 81 after 30 seconds of impregnation into the coil 80 was 50°. The impregnation property was somewhat good. Since the wetting improver 5 was added after phase inversion emulsification, a sufficient amount of the wetting improver 5 was not incorporated into the micelles 4 but was dispersed in the O / W emulsion 1. Therefore, it could penetrate into the narrow gaps between the coil windings 81 and had good impregnation properties. By using the wetting improver 5 as a nonionic surfactant, the intermolecular force between the nonionic surfactant and the micelles 4 increased. Although the viscosity was slightly higher than when using the copolymer represented by Chemical Formula (1), it could penetrate into the narrow gaps between the coil windings 81 and had good impregnation properties.
[0049] The viscosity of the insulating varnish composition 100 for motor impregnation in Example 3 was 60 mPa·s, and the contact angle with the coil winding 81 after 30 seconds of impregnation with the coil 80 was 34°, indicating very good impregnation. Because the wettability improver 5 was added after phase inversion emulsification, a sufficient amount of the wettability improver 5 was not incorporated into the micelles 4 but dispersed in the O / W emulsion 1, allowing it to penetrate even into the narrow gaps between the coil windings 81 and provide good impregnation. Furthermore, by using 2.5% by mass each of a solid nonionic surfactant and a liquid nonionic surfactant as the first dispersant 71 and second dispersant 72, respectively, with different activity energies, and performing phase inversion emulsification, the viscosity of the O / W emulsion 1 could be reduced. In addition, by adding the copolymer represented by chemical formula (1) as the wettability improver 5, the increase in intermolecular forces could be suppressed, and better impregnation was obtained than in Examples 1 and 2.
[0050]
[0051] The viscosity of the comparative motor impregnation insulating varnish composition in Comparative Example 1 far exceeded 500 mPa·s, making it difficult to penetrate the narrow gaps between the coil windings 81, resulting in very poor impregnation. It is presumed that this is because the wettability improver 5 was added before phase inversion emulsification, causing the wettability improver 5 to be incorporated into the micelles 41, preventing it from utilizing its wettability-improving function during impregnation into the coil 80.
[0052] The viscosity of the comparative motor impregnation insulating varnish composition in Comparative Example 2 was 200 mPa·s, which is not high. However, the contact angle with the coil windings 81 after 30 seconds of impregnation into the coil 80 was 62°, indicating poor impregnation due to difficulty in penetrating the narrow gaps between the coil windings 81. A copolymer represented by chemical formula (1) was added as the wettability improver 5, but it is presumed that because the wettability improver 5 was added before phase inversion emulsification, the wettability improver 5 was incorporated into the micelles 41, and its function of improving wettability could not be utilized when impregnating the coil 80. Furthermore, although two types of dispersants 71 and 72 were used, similar to Example 3 in which good results were obtained, it is presumed that the dispersants 71 and 72 were also incorporated into the micelles 41.
[0053] While this disclosure describes various exemplary embodiments, the various features, aspects, and functions described in one or more embodiments are not limited to the application of a particular embodiment, but are applicable individually or in various combinations to the embodiments. Accordingly, countless variations not illustrated are conceivable within the scope of the art disclosed herein. For example, these include modifying, adding, or omitting at least one component, or even extracting at least one component and combining it with a component from another embodiment.
[0054] 1, 11 O / W emulsion, 2 thermosetting resin, 3 curing agent, 4, 41 micelles, 5 wettability improver, 6 aqueous solution, 7 dispersant, 12 W / O emulsion, 21, 22 dispersed phase, 30, 31, 32 dispersion medium, 71 primary dispersant, 72 secondary dispersant, 80 coil, 81 coil winding, 100 insulating varnish composition for motor impregnation, 200 tank
Claims
1. An insulating varnish composition for motor impregnation, comprising: an O / W emulsion in which a hydrophilic component is used as the dispersion medium and a hydrophobic component is used as the dispersion phase, wherein micelles containing a thermosetting resin and a curing agent for initiating the curing reaction of the thermosetting resin are incorporated as the hydrophobic component; and a wettability enhancer that is not incorporated into the micelles but is dispersed in the O / W emulsion.
2. The insulating varnish composition for motor impregnation according to claim 1, wherein the wettability improving agent comprises at least one of a copolymer represented by the following chemical formula (1) and an ether-based surfactant having a hydrophobic reactive group represented by the following chemical formula (2).
3. The motor impregnation insulating varnish composition according to claim 1 or claim 2, wherein the wettability improver is contained in an amount of 0.1% by mass or more and 15% by mass or less of the total composition.
4. The insulating varnish composition for motor impregnation according to any one of claims 1 to 3, wherein the micelles have the hydrophobic components arranged facing inward, and the average particle size is 0.1 μm or more and 0.5 μm or less.
5. An insulating varnish composition for motor impregnation according to any one of claims 1 to 4, comprising 0.1% by mass or more and 10% by mass or less of a nonionic surfactant.
6. The insulating varnish composition for motor impregnation according to any one of claims 1 to 5, characterized in that the viscosity at 25°C is 1 mPa·s or more and 500 mPa·s or less.
7. The insulating varnish composition for motor impregnation according to any one of claims 1 to 6, wherein the proportion of the thermosetting resin is 5% by mass or more and 60% by mass or less of the total composition.
8. A method for producing an insulating varnish composition for motor impregnation, comprising the steps of: preparing a mixture of a thermosetting resin and a curing agent; dispersing the mixture in an aqueous solution with a dispersant consisting of a surfactant to produce a W / O emulsion in which the hydrophobic component is the dispersion medium and the hydrophilic component is the dispersed phase; inverting the W / O emulsion into an O / W emulsion in which the hydrophilic component is the dispersion medium and the hydrophobic component is the dispersed phase; and adding a wettability improver to the phase-inverted O / W emulsion.
9. The method for producing an insulating varnish composition for motor impregnation according to claim 8, wherein the dispersant is a nonionic surfactant.
10. A method for producing an insulating varnish composition for motor impregnation according to claim 8 or 9, wherein the dispersant is two or more surfactants with different activity energies, the first dispersant disperses the thermosetting resin and the curing agent, and the second dispersant forms micelles in which the thermosetting resin and the curing agent in the W / O emulsion are arranged inward and dispersed in the O / W emulsion.
11. The method for producing an insulating varnish composition for motor impregnation according to claim 10, wherein the first dispersant is solid at room temperature and the second dispersant is liquid at room temperature.
12. A method for producing an insulating varnish composition for motor impregnation according to any one of claims 8 to 11, wherein it is determined that the O / W emulsion has undergone phase inversion emulsification when at least one of the micelle diameter, viscosity, and stirring resistance reaches a set target value.