Transparent plastic case is an important component of electronic plastic enclosure, mainly used in junction box. So what is the main material of the transparent plastic box?
Commonly used transparent plastic materials are:
1. Polymethyl methacrylate (PMMA)
Commonly known as plexiglass, it is the plastic with the best optical properties. The mechanical and electrical properties of PMMA are general, the thermal expansion coefficient is 8-10 times that of inorganic glass, the long-term use temperature is only 80 degrees, and the hygroscopicity is high.
2. Polycarbonate (PC)
It is a transparent engineering plastic with excellent comprehensive properties, and the optical properties of PC are only lower than that of PMMA. However, it is heat-resistant and cold-resistant, and can maintain stable mechanical properties in the range of -135-120 degrees.
3. Styrene-methyl methacrylate copolymer (MS)
It is made of 70% styrene and 30% methyl methacrylate copolymer. The light transmittance of the copolymer is better than that of PS, while maintaining the good fluidity of PS.
4. Polystyrene (PS)
Together with PMMA and PC, they are called the three major transparent plastics. Its optical properties are worse than PMMA, but the moisture absorption rate is low, and the weather resistance of PS products is poor, and it will turn yellow and turbid after long-term storage and sunlight exposure.
5. Styrene acrylonitrile is often abbreviated as AS and SAN
It contains 20%-30% mass fraction of acrylonitrile monomer, and the rest is styrene monomer copolymerized with it. The transmittance of AS is similar to that of PS, but the refractive index is slightly lower. The maximum continuous use temperature of AS material is 10 degrees higher than that of PS, and the mechanical properties, weather resistance and stress cracking resistance are also improved.
