Mica sheet has the advantages of high strength, high modulus, low thermal expansion coefficient, high thermal conductivity, high temperature resistance, excellent dielectric properties, good chemical resistance, low solubility in water, small friction coefficient and low hardness. An important parameter of a sheet-like reinforcement is its diameter-to-thickness ratio, which relates to the efficiency of stress transfer from the weak polymer matrix to the strong reinforcement.
Due to the low diameter-thickness ratio of mica, a variety of methods for preparing mica sheets with high diameter-thickness ratios have been developed. Practice has proved that mica sheets are the most effective mineral materials that can reduce product warpage and increase stiffness and thermal deformation temperature.
In addition, mica sheet composites can maintain their high modulus without deformation at high temperatures. These properties, coupled with the light weight and low cost of mica sheets, are the goals of today’s industries looking for new materials.
Ⅰ. Application of mica sheet in rubber
Adding mica sheets to rubber can improve the aging resistance of rubber. In the rubber industry, mica sheets can improve the strength of rubber products, stabilize the quality, and achieve the reinforcing performance of semi-reinforcing carbon black. The combination of mica sheets and general-purpose carbon black in chloroprene rubber has a good synergistic effect. Proper mixing can reduce the cost of the rubber and improve the physical and mechanical properties of the rubber.
The mica sheets among mica products manufacturing are anti-friction fillers. The mica sheets in the friction material can not only reduce the friction coefficient but also reduce the wear of the material, thereby increasing the service life of the friction material. At the same time, it improves the oil resistance, water resistance and corrosion resistance of rubber.
Ⅱ. Mica sheets are used in thermosetting plastics
1. Polyester: Mica sheet reinforced polyester resin is mainly formed by spraying method and hand lay-up method. When spray forming, mica sheets are used as high-rigid linings for FRP products and acrylic thermoformed products. During hand lay-up, mica sheets are mainly used as reinforcement materials for the bottom of boats and half-decks of sailboats.
2. Phenolic, epoxy: mica sheets are mainly used in the manufacture of electrical devices that require high electrical performance.
3. A large amount of mica sheets are also added to polyurethane.
Ⅲ. Mica sheets are used in thermoplastics
The effect of high temperature mica sheet reinforced polypropylene is far better than other fillers such as talc, calcium carbonate and wollastonite. Adding 40% mica is equivalent to 30% glass fiber. In addition to the automotive industry as a user, mica sheet reinforced polypropylene is entering the field of household appliances.
2. Thermoplastic polyester
Thermoplastic polyester parts are easy to warp when cooled or used at high temperature. Reinforcing with mica sheets can not only inhibit warping, but also improve various physical properties.
Someone compared the reinforcement effect of various fillers with nylon 66 at 40% filling, and found that the tensile strength, bending strength, bending mold and heat distortion temperature of the material were greatly improved by mica sheets.
4. Other thermoplastics
In addition to the above polymers, mica sheets can also improve the strength and stiffness of polyvinyl chloride, polyethersulfone, polyphenylene sulfide, polyvinylidene fluoride and other fluoropolymers, and it has been found that mica sheets can improve the polymerization of styrenics. performance of things. However, mica sheets have an impact on their surface quality and impact resistance. The use of mica sheet reinforced plastics is growing rapidly.