Electrical Insulating Mica Tape: Complete Production Process and Procedure Analysis

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2026-04-08 08:04

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Complete Production Process Analysis of Mica Tape

 

Standardized Refined Process from Raw Material Selection to Finished Product Delivery

 

As a key fire-resistant insulating material for electrical equipment, mica tape features excellent high-temperature resistance, flame retardancy and insulation. It is widely used in wires and cables, new energy vehicles, rail transit, high-end appliances, motors, transformers and other fields.

 
From natural mica raw materials to qualified finished products, mica tape undergoes a standardized and precise production process. Strict control of each step is critical to ensuring product quality and performance.

 

 
 
 

Raw Material Selection & Pretreatment: Laying a Solid Foundation for Quality

 
 
 
 
 
 
The core raw materials of mica tape include mica paper, high-temperature resistant adhesives and reinforcing substrates. High-quality selection and pretreatment are fundamental to ensuring product performance.
 
Before production, muscovite and phlogopite are strictly sorted, crushed and exfoliated to remove impurities and unqualified laminae, producing uniformly thick mica flakes. These are further processed into mica paper (0.02–0.05 mm thick) with no holes or impurities, qualified insulation and tensile strength—acting as the key insulating substrate.
 
Meanwhile, reinforcing materials such as alkali-free glass cloth and polyester film, as well as high-temperature adhesives including epoxy and silicone adhesives, are prepared. Reinforcing materials are cut to match mica paper width and deburred. Adhesives are formulated to proper viscosity according to different temperature classes: 105, 155 and 180, fully preparing for subsequent production.
 
 
 

 

 
 
 

二、胶粘剂调配与涂布上胶：打造核心粘合层

 
 
 
 
 
 

 

Coating and gluing is a key process in mica tape production, directly affecting interlayer adhesion and service stability. It starts with adhesive preparation.
 
Resin, curing agent and optional diluent are mixed according to the formula, stirred at room temperature for 20–30 minutes. Viscosity is continuously monitored and adjusted to ensure uniform, particle-free glue. The mixture is then left to stand for 10 minutes for defoaming to avoid pinholes during coating.
 
The prepared adhesive is evenly applied onto the reinforcing substrate via a doctor-blade coater. Glue volume and thickness are controlled by adjusting the blade gap to ensure no missing coating, bubbles or uneven thickness.
 
The coated substrate is dried in a hot-air oven under two-stage temperature control for 5–8 minutes, achieving 30%–40% curing degree. It is then synchronously fed and tightly laminated with mica paper, laying the foundation for subsequent forming.

 

 
 
 

三、热压复合与固化处理：定型产品核心性能

 
 
 
 
 
 
The coated and dried reinforcing substrate and mica paper enter the hot-press lamination process, tightly bonded under a pressure of 0.3–0.5 MPa to form a stable structure: reinforcing layer — adhesive layer — mica layer. During lamination, conveying speed and unwinding tension are controlled in real time to effectively prevent wrinkles, edge warping and misalignment.
 

The laminated substrate is then cured in a curing oven via stepwise heating:

 

First, it is held at 120–140 °C for 30 minutes for pre-curing to remove solvent and avoid bubbling or deformation.

 

It is then heated to 160–180 °C and held for 60–90 minutes for full curing, allowing sufficient cross-linking of the adhesive.

 

Inert gas is introduced during curing to prevent resin oxidation and yellowing, with oven temperature controlled within ±5 °C to improve heat resistance, flame retardancy and mechanical strength.

 

After curing, the product is naturally cooled to room temperature for final setting, ensuring stable dimensions.

 
 

 

 
 
 

四、分切复卷：适配多元应用需求

 
 
 
 
 
 

 

 

The wide-width mica tape master roll after curing and setting cannot be used directly. It must be slit into finished rolls of specified width by high-precision slitting equipment, in accordance with application standards of various industries and customer requirements.
 
During slitting, the machine speed is controlled at 8–10 m/min to ensure strict edge flatness and avoid burrs or rough edges. After slitting, the rolls are rewound and inspected by both equipment and manual checking. Semi-finished products with surface defects, out-of-tolerance dimensions or substandard performance are rejected, ensuring uniform specifications and intact appearance of each roll.

 

 
 
 
 

 

 
 
 

五、全项质量检测：严守出厂品质关口

 
 
 
 
 
 
Quality inspection serves as a critical safeguard for qualified mica tape performance, covering appearance, physical properties, electrical properties and environmental performance.
 
Key tests include thickness, insulation resistance, voltage withstand strength, and heat resistance. Special focus is placed on verifying the temperature resistance grade, as well as compliance with low-smoke and environmental requirements. Only products meeting all standards can proceed to packaging.
 
 
 
 
 
Finished mica tape features excellent high temperature resistance, insulation and flame retardancy, making it a core material for insulation protection in electrical equipment. It is widely used in new energy vehicle high-voltage cables (withstanding above 150°C), large motor stator winding insulation, transformer coil wrapping, rail transit traction cable insulation and other applications.
 
From raw material selection to finished product packaging, every production process of mica tape is strictly controlled. Layer-by-layer stringent process standards ensure stable and reliable insulation performance.
 

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