Acrylic, also known as PMMA or Acrylic, is derived from English acrylic (acrylic plastic). The chemical name is polymethyl methacrylate, which is an important plastic polymer material developed earlier. It has good transparency, chemical stability and weather resistance, easy dyeing, easy processing and beautiful appearance. Has a wide range of applications. Ningbo RuiChang Commodity Packaging Co , Ltd . - Cosmetic Bottles Explain the Process Characteristics of Acrylic Emulsion Bottle Cosmetic Bottles
1. Polymethyl methacrylate contains a polar side methyl group, which has obvious hygroscopicity, and the water absorption rate is generally 0.3%-0.4%. It must be dried before molding, and the drying condition is drying at 80°C-85°C for 4-5h. .
2. Polymethyl methacrylate has obvious non-Newtonian fluid properties in the temperature range of molding processing. The melt viscosity decreases with the increase of shear rate, and the melt viscosity is also sensitive to temperature changes. Therefore, for the molding process of polymethyl methacrylate, increasing the molding pressure and temperature can significantly reduce the melt viscosity and achieve better fluidity.
3. The temperature at which polymethyl methacrylate starts to flow is about 160 ° C, and the temperature at which decomposition begins is higher than 270 ° C, and has a wide processing temperature interval.
4. Polymethyl methacrylate has a high melt viscosity and a fast cooling rate, and the product is prone to internal stress. Therefore, the control of the process conditions is strict during molding, and post-treatment is also required after the product is formed.
5, polymethyl methacrylate is an amorphous polymer, the shrinkage rate and its range of variation are small, generally about 0.5% -0.8%, which is conducive to the formation of plastic parts with higher dimensional accuracy.
6. Polymethyl methacrylate has excellent cutting performance, and its profiles can be easily machined to various required sizes.