1. Technology Introduction 

Polymethylmethacrylate (PMMA), also known as acrylic or acrylic glass as well as by the trade names Crylux, Plexiglas, Acrylite, Lucite, and Perspex. With the advantages of high transparency, low price and high polishability, it is frequently used in sheet form as a lightweight or shatter-resistant alternative to glass. 

With a light transmittance of 90%---92%, PMMA is 10 times tougher than silicon glass. PMMA is excellent in optical, insulating, processability and weather resistance. PMMA is soluble in organic solvents such as tetrachloroethylene, carbon, benzene, toluene dichloroethane, chloroform and acetone. PMMA has good heat resistance, toughness, hardness, with heat distortion temperature of 80 °C, bending strength of 110 Mpa and linear expansion coefficient of 0.00005-0.00009/°C.

The polymerization methods of MMA monomer to produce PMMA include solvent method, water suspension method, emulsion method and bulk polymerization method. To produce optical grade PMMA, bulk polymerization is proven to be the most stable and economic method among all these polymerization methods.

Whitefan Chemical developed innovative continuous bulk polymerization (partial monomer conversion) technology to produce PMMA, in which unreacted monomer was used as solvent. 

During the process, MMA monomer, comonomer, initiator and chain transfer agent are mixed and partially polymerized in the reactor.

The partially converted polymer/monomer mixture is fed to an extruder to remove monomer from the polymer and the MMA monomer is recovered by a distillation unit. 

Whitefan Chemical's has accumulated and improved the technology during practice, for example, the gelation effect of MMA polymerization has been greatly reduced by optimizing the control parameters of the reactor, and producing optical grade PMMA with excellent optical properties, discoloration and thermal stability. The process flow diagram is as follows:

2. Consumption and yield

The minimum yield of MMA monomer is 95-98% (equal to 0.95-0.98t PMMA/t MMA monomer) and the consumption rate of catalyst and auxiliary agent is 1%.