Polycarbonate Material Introduction

Polycarbonate (PC) is a non-toxic, odorless, colorless to pale yellow transparent solid polymer with carbonate groups in its molecular chain. It can be classified into various types based on the structure of the ester groups, such as aliphatic, aromatic, and aliphatic aromatic. Due to the low mechanical properties of aliphatic and aliphatic aromatic polycarbonate, their application in engineering plastics is limited.
Only aromatic polycarbonate has achieved industrial production. Due to the unique structure of polycarbonate, it has become the fastest-growing general-purpose engineering plastic among the five major engineering plastics.
Density: 1.18-1.22 g/cm ^ 3 Linear expansion rate: 3.8 × 10 ^ -5 cm/° C Thermal deformation temperature: 135 ° C Low temperature -45 ° C
Polycarbonate is colorless and transparent, heat-resistant, impact resistant, flame-retardant BI grade, and has good mechanical properties at normal operating temperatures. Compared to polymethyl methacrylate, polycarbonate has better impact resistance, higher refractive index, and better processability, and has UL94 V-0 flame retardant properties without the need for additives. However, polymethyl methacrylate is relatively cheaper than polycarbonate and can be used to produce large devices through bulk polymerization.
Polycarbonate has poor wear resistance. Some polycarbonate devices used for wear-resistant purposes require special surface treatment.
Extrusion plate
PC material must be dried to reduce its moisture content to below 0.02%. The molecular weight of PC board raw materials should be selected at 35000.
The length to diameter ratio of the extruder screw is 20:1, and the feeding section and metering section in the rod each account for 25% of the total length. The depth of the screw groove is constant, and the length of the compression section is half of the total length. The compression ratio of the screw is 2.5-3; The depth of the screw groove should generally be less than 4 millimeters; Mixing with pin screws yields better results.
The mesh group can adopt the 80/120/200/120/80 mesh type.
Hanger style machine heads are commonly used, but the cost is relatively high.
Rolling method
The rolling methods of sheets include horizontal extrusion of rolled sheets, inclined extrusion of rolled sheets, and downward or upward extrusion of rolled sheets. But currently the best method is the roller inclined rolling method.
Typical PC board extrusion conditions:
Machine temperature: 260 ℃, 280 ℃, 300 ℃, head temperature: 2801C, rolling roller temperature: upper roller 121-135 ℃, middle roller 129-139 ℃, lower roller 132-150 ℃, screw speed: 12-24 revolutions per minute, filter mesh set: 40/60/100 mesh.
PC boards can be used for car and airplane windshields, corrugated panels, folded panels, building window glass, sports facility ceiling glass, etc.
Other: PC can be blended with ABS to improve impact strength, and the maximum improvement is achieved when the ABS addition is 50%. When the ABS content is too low, such as 3%, the impact strength actually decreases.
PC can be blended with HDPE, and when the HDPE content is 30%, the blending effect is better, which can improve impact strength, enhance processing flowability, and make it easier to fill molds. The effect of LDPE co fermentation is poor, with delamination and cannot be used.
Film
PC can also be made into thin films with high puncture resistance, suitable for welding and heat sealing. PC film has high surface tension and does not require corona treatment before printing, resulting in good electroplating performance. Can be used for medicine, food packaging, and composite with cardboard as decorative panels.