From the winding coils all the way to the assembled finished product, insulation processes are integral to every stage of motor production. Motor insulation has always been a critical component of motor manufacturing. Based on years of production experience, once the motor's insulation structure is finalized, failures become rare—as long as components like the terminal block, enameled wire, lead wires, turn-to-turn insulation, shaft insulation, and slot insulation are carefully selected.

　　During the insulation process, numerous issues commonly arise due to improper selection of water-based insulating paint resins, inconsistent resin quality, or failure to strictly adhere to the established insulation procedures—issues that often manifest in diverse and sometimes subtle ways. Some problems may not be immediately apparent, only becoming evident after the entire machine has been assembled or once the product reaches the customer, potentially leading to significant financial losses for the company. Therefore, insulation process designers, technicians, and operators must pay close attention to this critical step, both in material selection and in adhering to the proper process practices. Here are several key requirements for motor-grade water-based insulating paint resins:

　　(1) Water-based Insulating Paint Resin: Electrical Properties

　　For electric tools, the key indicators are electrical strength (E) and insulation resistance coefficients (ρv, ρs). In this regard, the water-based insulating paint resins produced in China fully meet the required standards.

　　(2) Mechanical Properties of Water-Based Insulating Paint Resin

　　Electric tools are subjected to vibrational forces, thermal and cold shock stresses, as well as rotational centrifugal forces, leading to an immediate rise in temperature. Therefore, the water-based insulating paint resin must exhibit excellent adhesion properties—particularly strong adhesion at elevated temperatures—and the material itself should possess a high heat distortion temperature. This ensures that it retains sufficient impact strength and toughness even under intense mechanical stress, allowing the motor to operate safely and maintain a long service life despite harsh environmental conditions.

　　Permeability is crucial in impregnation varnishes. Coils coated with paints that have poor permeability are prone to developing deep, uncoved areas, which prevent other insulating materials from performing optimally in those critical regions. This can lead to weak spots, increasing the risk of breakdown or significantly reducing the product's lifespan. Generally, paints that are over-polymerized or improperly formulated with the wrong solvents tend to exhibit poor permeability. In some cases, it’s essential for enameled wires with smaller diameters (e.g., Φ) and rotors thinner than 0.20 mm to demonstrate excellent paint penetration.

　　(3) Thermal Performance of Water-Based Insulating Paint Resin

　　When electric tools are in operation, the rising temperatures can cause high-polymer materials to undergo cracking, hydrolysis, oxidation, and other degradation processes. These phenomena make the materials brittle and prone to developing cracks, ultimately leading to reduced insulation resistance, diminished dielectric strength, weaker mechanical integrity, and increased stress-induced deformation. Therefore, enhancing the heat resistance of insulation materials is crucial for ensuring the safe operation of motors and improving their overall power output.

　　(4) Physical Properties of Water-Based Insulating Paint Resin

　　The coating should have moderate viscosity, excellent permeability, and an appropriate amount of paint application; it must feature a high solid content to minimize the proportion and evaporation of solvents. Additionally, it should exhibit low water absorption, a light color, and demonstrate outstanding resistance to both cold temperatures and thermal shock.

　　(5) Chemical Properties of Water-Based Insulating Paint Resin

　　Due to the varying applications of insulating coatings, it is essential to consider resistance to humid and hot climates, solvent resistance, and compatibility with other insulation materials.