Products · PC
Polycarbonate (PC) is a transparent amorphous engineering polymer with a unique combination of high impact strength (the highest of any transparent polymer), optical clarity, dimensional stability, and heat resistance (HDT 130-140°C). PC is the workhorse for optical lenses, electrical enclosures, IT equipment, food contact applications, and medical device housings. The bisphenol-A (BPA) backbone is the subject of ongoing health-and-safety discussions; PC grades for food contact and medical use are specifically formulated to meet FDA and EU regulations. Reference grades from SABIC (Lexan), Covestro (Makrolon), and Teijin (Panlite) cover the full property range.
Section 1
A reference overview of the molecular architecture and the design variables that govern the performance of this polymer family.
PC is produced by the interfacial polycondensation of bisphenol A (BPA) and phosgene (or by melt transesterification with diphenyl carbonate). The repeating unit has the BPA backbone with carbonate (–O–CO–O–) linkages, giving an amorphous polymer with high Tg (145-150°C). The bulky BPA structure prevents crystallization, giving PC its characteristic transparency. The combination of high Tg and amorphous structure gives PC high impact strength (the highest of any transparent polymer), dimensional stability, and optical clarity. The carbonate linkage is susceptible to hydrolysis at high temperatures in alkaline environments — a key processing and application constraint.
Section 2
Typical property ranges across commercial grades. Test methods are listed in the rightmost column for traceability to public manufacturer data sheets.
PC's defining properties are high impact strength (250-900 J/m Izod, the highest of transparent polymers), high Tg (145-150°C), optical transparency (>89% light transmission), and FDA food-contact compliance for specific grades. The combination of transparency and impact strength is unique to PC.
| Property · 性能 | Unfilled PC | 10% GF PC | Test Method · 测试方法 |
|---|---|---|---|
| Density · 密度 | 1.19 – 1.22 g/cm³ | 1.25 – 1.30 g/cm³ | ASTM D792 |
| Tg · 玻璃化温度 | 145 – 150 °C | 145 – 150 °C | DSC |
| Tensile Strength · 拉伸强度 | 55 – 75 MPa | 60 – 80 MPa | ASTM D638 |
| Flexural Modulus · 弯曲模量 | 2.2 – 2.4 GPa | 3.5 – 4.0 GPa | ASTM D790 |
| Elongation at Break · 断裂伸长 | 100 – 150 % | 5 – 10 % | ASTM D638 |
| HDT (1.82 MPa) · 热变形 | 125 – 135 °C | 135 – 145 °C | ASTM D648 |
| Izod Notched Impact · Izod 缺口冲击 | 600 – 900 J/m | 100 – 200 J/m | ASTM D256 |
| Light Transmission · 透光率 | 88 – 91 % | Opaque | ASTM D1003 |
Section 3
The major application areas for this polymer family, each illustrated with a brief description of how the material is specified and used.
PC is the dominant material for optical lenses, optical windows, and protective shields. The combination of high transparency, high impact strength, and dimensional stability is unique. Common in eyewear, safety glasses, automotive headlamp lenses, and machine guards.
Flame-retardant PC grades (UL94 V-0) are used in electrical enclosures, IT equipment housings, laptop shells, and power tool bodies. The combination of high impact strength, flame retardance, and processability is valued in consumer and IT applications.
FDA-compliant PC grades are used in food contact applications: water bottles (reusable), baby bottles, food storage containers, and kitchenware. The combination of transparency, impact strength, and heat resistance (top-rack dishwasher safe) is valued. Note: PC for infant feeding applications has been subject to BPA migration discussions; alternative copolyesters (Tritan, Eastar) are available for sensitive applications.
PC is widely used in medical device housings (where impact strength and transparency are needed), surgical instrument components, and high-impact medical device shells. PC can be sterilized by gamma irradiation, EtO, and limited steam cycles.
Section 4
Key processing parameters and equipment considerations. Contact our business manager for grade-specific processing recommendations.
| Melt Temperature | 280 – 320 °C; mold temperature 80 – 120 °C |
| Drying | 120 °C for 4 – 6 hours (moisture < 0.02%) |
PC is sensitive to hydrolysis — wet resin rapidly loses molecular weight, reducing impact strength dramatically. Aggressive drying is mandatory. PC is also susceptible to environmental stress cracking (ESC) in contact with many solvents — design should avoid sharp corners and high molded-in stress. Annealing at 120-130°C for 1-2 hours can reduce molded-in stress for critical optical parts.
Section 5
A summary of when this polymer family is the right choice and what to consider as alternatives. For project-specific grade selection, contact our business manager.
Choose PC when the application requires transparent engineering polymer with high impact strength and HDT > 120°C. For chemical resistance, consider PMMA (lower impact) or PSU (higher cost). For higher temperature (Tg > 180°C), consider PEI or PES. For better chemical resistance with moderate transparency, consider PP or PMP. For BPA-sensitive applications, consider copolyester (Tritan) or PP.
Section 6
Reference grades from publicly available manufacturer catalogs. Complete catalog available on request.
| Grade | Manufacturer | Key Properties | Typical Use |
|---|---|---|---|
| Lexan® 141R | SABIC | Unfilled · Molding grade · Standard | General purpose · Optical · Consumer |
| Lexan® 3412R | SABIC | 20% GF · High stiffness | Structural · High-temperature applications |
| Makrolon® 6555Internal snapshot · original TDS on request | Covestro | Unfilled · High flow · Medical grade | Medical · Thin-wall · High clarity |
| Lexan® 920A | SABIC | FR · UL94 V-0 · 1.5 mm | IT equipment · Electrical enclosure · FR applications |
Section 7
Cross-references to industry-specific applications and case studies.