What is the Muscovite Mica Tape, Synthetic Mica Tape, Phlogopite Mica Tape ?

Mica Tape

General Questions and Answers

Q. Why has CWP partnered with Isovolta?

A.  Isovolta is among the leading international manufacturers of electrical, composite and technical laminates for electrical insulation.  Isovolta US division manufactures five unique grades of mica papers that are used in the production of high dielectric mica tapes and wrappers.  This unique manufacturing facility lends itself to the design and manufacture of specialty applications designed for your custom requirements.   

Mica Tape Magnet Wire Georgia

Q.  What is Mica?

A.  Mica is the name given to a group of minerals of related composition and similar physical properties, most notably perfect basal cleavage, which means they can be split readily in one plane into a great number of thin, tough laminates.



Q.  Where does Mica come from?

A.  Mica is mined chiefly in India, Madagascar, Canada, and the United States.



Q.  How many types of Mica are there?

A.  Of seven common varieties of mica, only Muscovite and Phlogopite are of any importance to the electrical industry.



Q.  What are Muscovite and Phologopite Mica?

A.  Muscovite mica called white or India mica, does have better voltage endurance characteristics than Phlogopite.   For that reason, Muscovite is preferred for motor and generator applications.  Phologopite is referred to as Amber mica. Phlogopite mica is used for higher temperatures over 600°C.  Phlogopite is found in many wire and cable applications, where one must maintain circuit integrity during fire conditions.


Q. Why is Mica Used for Electrical Insulation?

A.  It has extremely high dielectric strength, low electric loss, high surface and volume resistivity, excellent thermal stability, and high shear and tensile strengths.


Q.  What are some properties of Mica?

A.  It is completely inert to the action of water, acids, alkalies, oils and solvents. It is fireproof, non-flammable, unaffected by temperatures of 1200°F, and is resistant to the oxidizing action of electrical discharges.


Q.  What is Mica Paper?

A.  Mica paper is actually a paper like material consisting of miniature flakes of either Muscovite or Phlogopite mica held together by natural cohesive force between adjacent flakes.  This is not to be confused with "cellulose" paper.  Mica paper is 100% mica.


Q. What is mica tape?

A.  Mica tape is an inorganic high dielectric tape manufactured with mica paper and laminated to various reinforcing substrates to enable ease of handling.  Tapes are available in fully cured, VPI, resin rich (press cure) and B stage.


Q. What are the backings for mica tape?

A.  Backings are woven and non woven glass cloths, non woven polyester web, and various  polyester films including polyimide.


Q. What are the advantages of one backing over the other?

A. The backing is dependent upon the application.  For example polyimide film for high temperature applications.  The thermal class of the application helps determine the bonding agent and backings selected.


Q. What is a conductor tape? How is it used?

A.  It is the strand insulation used to wrap around the individual conductors.   Typically used when turn stresses are elevated beyond standard enamel or daglas over enamel wire coatings.


Q. What is a ground wall tape? How is it used?

A.  Ground wall tape is wrapped around your formed coil, and is used as the major dielectric barrier in the insulation system. 


Q. Are mica tapes pressure sensitive?

A. No


Q. How many manufacturers are there in the United States producing mica paper?

A.  Isovolta is the only manufacturer of mica paper in North America and offers five unique grades of mica paper.


Q. What is a mica wrapper?

A. Mica wrapper is a mica roll slit to width to insulate the slot section of a form wound coil.


Q. What does resin rich mean?

A.  Resin Rich is B staged or semi cured mica tapes, waiting to be processed in a heated environment.


Q. What is the major advantage and benefit of using a mica tape?

A.  The advantages of mica tape are good dielectric strength, inorganic content, does not support corona, thermal conductivity, low dissipation factor and easily impregnated with resin.


Q. What does the term "flat glass mica" mean?

A. Woven glass cloth where individual stands are not twisted giving strength while gaining space.  The yarns used to produce this flat glass cloth could be compared to ribbon like as opposed to rope like in appearance.  The much smoother and more uniform glass cloth allows for additional space in the slot. 


Q. What is the benefit of "flat glass mica" over standard mica?

A.  In flat glass mica the flat glass is not heat cleaned so virtually all of its strength is retained, while reducing ground wall thickness over traditional mica tapes using glass cloth.


Q. Where can my customer get "flat glass mica" from?

A.  Call your local Isovolta sales representative.

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Muscovite Mica Tape, Synthetic Mica Tape, and Phlogopite Mica Tape: Comprehensive Overview

1. Introduction
Mica tapes are essential components in various industrial applications, particularly in the cable manufacturing industry. They are primarily used for fire-resistant and high-temperature-resistant cables. These tapes are made using different types of mica minerals, which have unique thermal, electrical, and mechanical properties. This document provides a detailed explanation of three commonly used mica tapes: Muscovite Mica Tape, Synthetic Mica Tape, and Phlogopite Mica Tape.

2. Understanding Mica
Mica is a group of naturally occurring silicate minerals known for their ability to withstand high temperatures, resist electricity, and provide excellent insulation. Mica minerals are categorized based on their composition and properties. The two main types of mica used in industrial applications are muscovite and phlogopite. Additionally, synthetic mica is produced for specialized uses.

3. Types of Mica Tapes
3.1 Muscovite Mica Tape
Muscovite mica, also known as potash mica, is a hydrous silicate of aluminum and potassium. It has excellent electrical insulation properties and a high dielectric strength, making it suitable for fire-resistant cables.

Properties of Muscovite Mica Tape:
- Thermal Resistance: Muscovite mica can withstand temperatures up to 700°C.
- Electrical Insulation: It offers high dielectric strength, ensuring reliable electrical insulation.
- Mechanical Strength: The tape has good mechanical strength, making it suitable for applications where durability is essential.
- Flexibility: Muscovite mica tape is flexible and can be easily wrapped around cables without breaking.

Applications of Muscovite Mica Tape:
- Used in power cables and control cables.
- Applied in fire-resistant cables for buildings, tunnels, and transportation systems.
- Utilized in aerospace and defense industries where high-temperature resistance is critical.

3.2 Synthetic Mica Tape
Synthetic mica, also known as fluorophlogopite, is a man-made material designed to replicate the properties of natural mica while offering enhanced performance. It is created by melting and crystallizing various silicate compounds.

Properties of Synthetic Mica Tape:
- Superior Thermal Resistance: Synthetic mica can endure temperatures up to 1100°C.
- High Purity: Since it is manufactured under controlled conditions, synthetic mica has fewer impurities than natural mica.
- Improved Dielectric Strength: It offers superior electrical insulation compared to natural mica.
- Moisture Resistance: Synthetic mica is less hygroscopic, meaning it absorbs less moisture from the environment.

Applications of Synthetic Mica Tape:
- Used in high-temperature cables and wires.
- Ideal for applications in the nuclear industry due to its high purity and resistance to radiation.
- Employed in the manufacturing of fire-resistant cables for critical infrastructure.

3.3 Phlogopite Mica Tape
Phlogopite mica is a hydrous silicate of potassium and magnesium. It has a brownish-golden appearance and is known for its high-temperature stability.

Properties of Phlogopite Mica Tape:
- Exceptional Thermal Resistance: Phlogopite mica can resist temperatures up to 1000°C.
- Good Electrical Insulation: It offers reliable electrical insulation under extreme conditions.
- Chemical Stability: Phlogopite is chemically stable and resistant to most acids and alkalis.
- Flexibility and Durability: Like muscovite, phlogopite mica tape is flexible and durable.

Applications of Phlogopite Mica Tape:
- Widely used in fire-resistant cables.
- Preferred in industries such as steel, glass, and metallurgy where high temperatures are common.
- Used in high-temperature furnace insulation and induction heating systems.

4. Comparison of Mica Tapes
The table below summarizes the key differences among muscovite mica tape, synthetic mica tape, and phlogopite mica tape:

Property	Muscovite Mica Tape	Synthetic Mica Tape	Phlogopite Mica Tape
Thermal Resistance	Up to 700°C	Up to 1100°C	Up to 1000°C
Electrical Insulation	High	Very High	Moderate to High
Flexibility	Good	Good	Good
Moisture Absorption	Moderate	Low	Low
Chemical Resistance	Moderate	High	High

5. Manufacturing Process
Mica tapes are manufactured by impregnating mica paper with a heat-resistant resin and then laminating it onto a supporting material, such as glass cloth or polyester film. The process involves the following steps:

5.1 Mica Paper Production
- Natural or synthetic mica is split into thin layers and ground into fine flakes.
- These flakes are formed into sheets using a paper-making process.

5.2 Impregnation
- The mica paper is impregnated with a heat-resistant silicone or epoxy resin to enhance its mechanical strength and thermal stability.

5.3 Lamination
- The impregnated mica paper is laminated onto a supporting material to provide additional strength and flexibility.

5.4 Final Processing
- The laminated mica tape is cut into rolls of various widths and lengths according to customer specifications.

6. Applications in Cable Industry
Mica tapes are widely used in the cable industry for fire-resistant and high-temperature-resistant cables. These cables are crucial in ensuring safety in critical environments, such as:

- Building wiring
- Railway and subway systems
- Oil and gas industries
- Aerospace and defense applications
- Nuclear power plants

7. Conclusion
Muscovite mica tape, synthetic mica tape, and phlogopite mica tape each have unique properties that make them suitable for different applications. Understanding the differences among these tapes is essential for selecting the right material for specific industrial needs. Whether it's high dielectric strength, exceptional thermal resistance, or chemical stability, mica tapes play a vital role in enhancing the safety and performance of cables used in critical environments.