Home > > Tech-info > PMAA > Processing Condition LG PMMA Resin can be used without preliminary drying. But in case of long-term storage or poor storage, it may absorb moisture excessively. Moisture contents of 0.1% and over can cause silver streaks or blowholes inside. Hence, it is desirable to perform preliminary drying in accordance with the following conditions.   Grades Drying Temperature Drying Time General Purpose Grade Optical Grade 70 ~ 80℃ 4 ~ 6 hours Impact Resistance Grade 60 ~ 70℃ Grades Drying Temperature Molding Temperature Injection Pressure EH910 240 ~ 270℃ 70 ~ 90℃ 800 ~ 1,500kg/cm2 IH830 220 ~ 260℃ 70 ~ 80℃ 800 ~ 1,500kg/cm2 IG840 210 ~ 250℃ 70 ~ 80℃ 800 ~ 1,500kg/cm2 IF850 200 ~ 240℃ 60 ~ 80℃ 600 ~ 1,200kg/cm2 IF870 190 ~ 240℃ 60 ~ 80℃ 600 ~ 1,200kg/cm2 Impact Resistance Grade 200 ~ 250℃ 60 ~ 70℃ 500 ~ 1,100kg/cm2 In case that a molded product contacts organic solvent, annealing is absolutely necessary for the product. To perform annealing effectively, fix the temperature at the upper limit, where defective molding products don't appear. If you steep a product in 90% alcohol for 15 minutes, you will learn more about it.   Grades Temperature Time EH910, EG920, IH830 80 ~ 90℃ 3 ~ 5 hours IG840 70 ~ 80℃ IF850 60 ~ 70℃ IF870 60℃ Impact Resistance Grade 60 ~ 70℃