Polycarbonate (PC) is a transparent, and very strong and durable plastic. It is impact resistant, thermally stable and lightweight. It’s been popular in many industries because of these properties.
Modern manufacturing employs an important process known as injection molding. This enables companies to mass produce parts at great speed and economy. It is perfect for making shapes of an exact and complex kind.
I. Properties of Polycarbonate (PC)
Chemical Structure
The thermoplastic polymer polycarbonate (PC) is mainly created from Bisphenol A (BPA). The BPA-PC type is one of the most widely used forms of BPA polymer. The material is synthesized using two main methods: Including interfacial polymerization and melt polymerization.
What is Polycarbonate (PC)? Why is it so tough impact resistant plastic that is so transparent? It is shock resistant, heat resistant and lightweight. All these make it a very popular product in many sectors.
Injection molding is a critical technology in the manufacturing world today. It lets firms create huge numbers of components in a very short time. The approach is perfect for constructing complex, exact shapes.
Melt Polymerization eliminates solvents by mixing BPA with diphenyl carbonate. This is a sustainable process for manufacturing high-performance polycarbonate.
The density of the polymer makes a big difference. A higher molecular weight increases the material’s
durability and impact strength. This makes high-molecular-weight polycarbonate the best choice for applications requiring greater strength, including safety gear and barrier systems.
Physical Properties
Polycarbonate is famed for its remarkable mechanical qualities. It is tough, transparent, and heat resistant.
Impact Strength:
The Izod impact strength for polycarbonate is 600-800 J/m and its Charpy impact strength is 20-30 kJ/m2. With this superior toughness, it doesn’t crack in a fall, and so things like helmets, car parts, and bulletproof glass are all applications for it.
Light Transmission:
80-90% of the light passes through, making it almost as transparent as glass. This feature makes polycarbonate the perfect material for lenses, light shields, and display cases.
Heat Deflection Temperature (HDT):
The HDT of the polycarbonate is 140°C (264°F) 1.8 MPa (264 psi). HDT stands for heat deflection temperature, which is measured in degrees c and represents the temperature at which a test specimen generates a deflection of 0.25 inch at specified speed and load.
That’s why it has a consistent shape and good performance at high temperatures — perfect for electrical enclosures and car interiors.
Specific Gravity:
The density of polycarbonate at 1.20 g/cm3 has something for you. What does it mean? It means that it’s both light and durable, and the touch of polycarbonate doesn’t sting.
Refractive Index:
You will notice that It has a refractive index of 1.58, making it suitable for optical grade products. UV Stabilizers increase sun protection and extend outdoor useability. To help ensure safety, flame retardants minimize flammability, which is essential in electronics and construction projects.
Mechanical Properties
Polycarbonate’s mechanical properties demonstrate its flexibility and adaptability to different environments.
Tensile Modulus:
You should also know that its tensile modulus of 2.5-3.5 GPa. This allows polycarbonate to face high forces without significant deformation.
Elongation at Break:
The fabric can stretch 50-100% before it tears – making it elastic and insensitive to sudden cracking. This adaptability is necessary for use cases such as snap-fit connectors.
Flexural Modulus:
You should know that flexural modulus of 2.5-3.5 GPa means it significantly bears bending forces. Subsequently, they can be used in construction elements.
Fatigue Strength:
Polycarbonate has a 20-30 MPa fatigue strength, meaning that it can stand multiple stressors over the long term. It is therefore suited to moving components such as hinges and gears.
Polycarbonate’s mechanical characteristics, too, vary depending on the environmental conditions:
At higher temperatures it becomes more flexible but less rigid and is thus good for use where both flexibility and heat resistance are desired. Higher strain rates increase its toughness, allowing it to absorb energy more efficiently when struck.
Uses of Polycarbonate (PC) in Injection Molding
Automotive
Polycarbonate is used extensively in the car industry. It is most often used for headlight and taillight lighting lenses. For their safety, these lenses depend on polycarbonate’s clarity and durability.
The interior trim parts ( dashboards and door sills) also utilize this material. Polycarbonate can also be used as a lightweight substitute for conventional glass windows, thereby maximizing efficiency. It is used as an element in battery casings in electric cars. It is heat-resistant and electrically insulated, which makes it the perfect choice for ensuring security in critical systems.
Medical Devices
Polycarbonate is important in medicine because of its biocompatibility. It is extremely safe, which means it can be implanted in devices that expose human tissue. This material can also be sterilised using gamma radiation or ethylene oxide to make it suitable for reusable appliances.
Polycarbonate is typically used for surgical instruments where accuracy and durability are critical. It is also used in blood oxygenators and dialysis equipment. Its transparency permits visual measurement of fluid during medical interventions.
Consumer Products
Polycarbonate is an all-time favorite for household goods due to its toughness. It is ubiquitous on optical discs, like CDs and DVDs, where its sharpness ensures high-quality data storage. Polycarbonate also protects the safety glasses and goggles against impacts.
These products offer the vital protection required in highly regulated environments. Polycarbonate is commonly found in water bottles and food containers. Its hardness makes it durable, and the BPA-free versions meet the needs of the health conscious user.
Other Applications
Polycarbonate’s usefulness isn’t limited to the building industry. In buildings, it is applied for roofing and glazing. These uses take advantage of the material’s light weight and resistance to UV radiation. In security, bulletproof windows are usually constructed from polycarbonate. It’s both powerful and transparent, so it works for banks and cars.
In electronics polycarbonate serves as a circuit board substrate. Also, because of its insulation capacity, it can also be used as a tough casing material. Polycarbonate is used in the cockpits of airplanes in the aviation field. It’s lightweight and strong, thus lowering weight without sacrificing safety.
Processing Considerations for Polycarbonate (PC)
Molding Conditions
You should be careful when cutting polycarbonate. The crucial thing is that you need to monitor the temperature. The melt temperature should be 280-320°C (536-608°F). This range allows the material to move smoothly without breaking down. Set the mold temperature to 80-120°C (176-248°F).
This makes the surface cleaner and produces uniform parts. You’ll need to maintain pressure and wait for a cooling time. Control of these variables avoids warping and shrinkage of the final product.
Drying and Handling
Polycarbonate should be properly dried and molded. It absorbs water quickly, and that may impact the finished product. The most common dryers are desiccant dryers and hot air dryers. Such processes extract moisture from the substance.
Polycarbonate should be kept dry, cool and out of the reach of moisture. When you’re handling the cloth, try not to scratch or scratch it. Damage can degrade the integrity of the moulded components.
Mold Design
An accurate mold design is the key to polycarbonate molding. The gating, venting, and runner arrangements must all be optimized for material flow. Hot runners work well with polycarbonate moulding.
These machines streamline and minimize waste by removing runners and sprues. A well designed mold also reduces cycle time and produces higher-quality parts.
Troubleshooting
Sink marks, warpage, short shots, and jetting are some of the most common polycarbonate molding defects. Sink marks occur when cooling is not uniform. This can be compensated for by increasing holding pressure and cooling time.
Warpage might result from a loss of shrinkage or low mold temperature. It can be reduced by optimizing mold design. Short shots happen when the mould doesn’t fill all the way. This can be overcome by increasing the injection pressure or melting temperature.
Jetting happens when the melt velocity is too high. This can be remedied by modifying the gating design and slowing down the injection rate.
Conclusion
Polycarbonate (PC) is a durable material. It is highly transparent, impact resistant and heat resistant. This makes it ideally suited for injection molding in most fields. Manufacturers can ensure good quality parts by controlling the mold conditions, drying, and handling.
RJC Mold specializes in polycarbonate injection molding. Our company leverage PC’s high impact resistance and clarity. Contact us for your PC molding parts.
