Transparent Polycarbonate PC Sheets PC Plate
Molecular Structure and Basic Properties
Ultra-High Impact Resistance: The benzene rings in the PC molecular chain provide rigid support, while ether bonds (-O-) and carbonate groups (-C(=O)-O-) impart flexibility to the chain segments, forming a molecular network that combines rigidity and flexibility. Its Charpy notched impact strength reaches 800-1200 J/m (ISO 179 standard), 15-20 times that of ordinary glass (approximately 50 J/m) and 5-8 times that of PMMA (approximately 100-150 J/m). Even at -40°C, it maintains an impact strength of ≥500 J/m (common plastics such as PS have an impact strength that drops sharply to <50 J/m at -20°C).
Excellent Optical Clarity: PC sheet boasts a light transmittance of ≥89% (close to 92% for glass), a haze of ≤1% (compared to 2%-3% for ordinary acrylic), a surface gloss of ≥110 GU (high gloss, visual clarity), and is colorless and transparent (comparable to optical-grade glass). It is suitable for applications requiring extremely high light transmittance, such as greenhouse lighting and display screen windows.
High Glass Transition Temperature (Tg): The Tg is approximately 145-150°C (common PC is 140-150°C, with some high-temperature-resistant grades reaching 160°C). This means the material maintains rigidity (resistance to softening and deformation) below 145°C and can withstand short-term temperatures of 180-200°C (common plastics like PVC have a Tg of only 70-80°C and are prone to deformation at high temperatures).
Excellent processing fluidity: The melt flow rate (MFR, at 260°C/2.16kg) is typically 5-30 g/10min (this can be adjusted through formulation: a lower MFR is used for enhanced rigidity in thick panels, while a higher MFR is used for complex injection molding of thin panels). This is slightly lower than ABS (5-30 g/10min), but allows for complex structural processing through thermoforming processes such as vacuum forming and hot bending.
Excellent Overall Performance
High Strength and Lightweight: Tensile strength ≥60-70 MPa (common PC: 60-80 MPa, acrylic: 70-80 MPa but with poor impact resistance), flexural strength ≥90-110 MPa, and elastic modulus ≥2200-2400 MPa. At the same time, its density is only 1.20-1.22 g/cm³ (approximately half that of glass and one-third that of aluminum), achieving both structural strength and lightweight properties (for example, reducing the weight of large skylights reduces the cost of supporting structures).
Weather and UV Resistance: Unmodified PC is susceptible to molecular chain breakage (causing yellowing and embrittlement) under prolonged ultraviolet (UV) exposure. However, by adding hindered amine light stabilizers (HALS) and UV absorbers (such as benzotriazoles), PC sheets can achieve a UV-protective layer (0.1-0.3 mm thick) that remains yellow-free for ten years. (Ordinary untreated PC exhibits noticeable yellowing after just one to two years of outdoor use.) For example, a two-layer co-extruded PC sheet (with an outer UV-protective layer and an inner transparent substrate) exhibits a color change of ΔE ≤ 1.5 (almost imperceptible to the human eye) after 5,000 hours of outdoor exposure, while retaining ≥90% impact strength.
Flame Retardancy and Fire Resistance: The oxygen index (OI) of ordinary PC is approximately 26-28 (classified as a flame-retardant material, but not meeting strict fire protection standards). By adding brominated epoxy resins and phosphorus-based flame retardants (such as TPP), the OI can be increased to ≥32. This meets UL94 V-0 (self-extinguishing within 10 seconds after removal from the flame, with no ignition from dripping) or V-2 (dripping but no sustained combustion) standards, making it suitable for applications requiring high fire protection (such as electronic and electrical equipment enclosures and public building partitions).
Self-Extinguishing and Low Smoke Toxicity: It generates low smoke (over 60% less than PVC) during combustion and does not release toxic halogen gases (environmentally friendly PC uses a halogen-free flame retardant system). It meets the B1 (flame-retardant) combustion performance grade for building materials or the GB 8624-2012 standard.
Precision Processing and Dimensional Stability
Processability: PC sheets can be processed through a variety of processes, including extrusion (thickness range 1-20 mm, width ≤ 3000 mm), thermoforming (such as vacuum forming into complex curved surfaces), CNC cutting (precision punching/milling), and hot bending (localized heating forming), meeting diverse needs in architecture, industry, consumer electronics, and other fields. For example, the thickness tolerance of extruded sheets is ±0.2 mm (common plastic sheets are ±0.3 mm), and the minimum wall thickness of thermoformed parts can reach 0.8 mm (complex structures can be formed in one go).
Dimensional Stability: The linear thermal expansion coefficient is 6.5 × 10⁻⁵/°C (common glass is 8.5 × 10⁻⁶/°C, but PC needs to consider temperature fluctuations). The dimensional change rate is ≤ 0.3% within the range of -40°C to 120°C (common acrylic is 0.5% to 0.7%), making it suitable for applications requiring stringent tolerances, such as precision instrument windows.
Water absorption rate: Water absorption rate ≤ 0.2% (common PA6 is 1.5% - 2%, which is prone to dimensional changes due to water absorption). No pre-drying is required for use in normal environments (performance is basically stable after short-term storage in a humid environment).
