Silicone vs Polycarbonate

If you want to customize a batch of medical equipment that can be sterilized at high temperatures, should you choose silicone or polycarbonate? As two common engineering materials, silicone and polycarbonate both have many strengths and are suited to a wide range of needs, but they are very different in nature. This article will deeply compare these two materials. I believe you will know the answer after reading it.

What is Silicone?

There are two types of silicone. One is industrial silicone, which is a desiccant. The other type is silicone rubber, which is usually called silicone in our daily life. Its main components are silicon, oxygen, carbon and hydrogen. It is neither plastic nor natural rubber, but a soft, flexible, safe and non-toxic synthetic silicone rubber.

What is Polycarbonate?

Polycarbonate is a polymer and a very outstanding thermoplastic engineering plastic with high strength, high transparency and excellent impact resistance. It is of great importance in modern industry, and is the king of plastics deservedly!

What are the Differences Between Silicone and Polycarbonate?

Mechanical Properties

• Silicone has outstanding high elasticity and flexibility.
• Polycarbonate exhibits extremely high rigidity and hardness.
• Comparison: Silicone is “soft”, while PC is “hard”. You can also allow the two materials to complement each other to the greatest extent possible, making the product both rigidly supportive and flexible to the touch.

Optical Properties

• Silicone can be made transparent or semi-transparent, but its light transmittance and optical purity are usually inferior to that of polycarbonate, and it is easier to light scattering.
• The light transmittance of polycarbonate can exceed 90%, achieving a high level of light transmittance similar to glass and extremely low haze.
• Comparison: PC is undoubtedly the optical champion. It is also the first choice for precision optical components. For any materials used in optical products, you can give priority to choosing polycarbonate.

Thermal Properties

• Silicone has an extremely wide temperature resistance range ( -60°C to 250°C) and can operate stably at both extremely high and low temperatures.
• Polycarbonate has limited heat resistance (long-term working temperature: -40°C to 130°C, heat deflection temperature: approximately 130°C-140°C), and may experience creep at high temperatures.
• Comparison: Silicone is the king in extreme temperatures.

Biological Stability and Safety

• Silicone rubber is the benchmark material for food contact and medical implant applications because of its superior biocompatibility and well-recognized safety, often free of bisphenol A (BPA).
• Although medical-grade polycarbonate also exists, the bisphenol A (BPA) component of its traditional formulation is controversial, and its public safety trust is relatively low.
• Comparison: In terms of the perception of “safety”, silicone has more advantages. So you can choose silicone as the preferred material for medical and food applications.

Durability

• Silicone has average wear resistance but it has outstanding fatigue resistance.
• Polycarbonate is wear-resistant and has high hardness, but it may crack when subjected to force.
• Comparison: PC is more wear-resistant, while silicone is better at resisting pressure.

Processing and Cost

• Silicone is mostly molded or injection molded through a process that requires heating and vulcanization, and its production cycle is usually longer.
• Polycarbonate is highly suitable for large-scale injection molding and has extremely high production efficiency.
• Comparison: In large-scale production, the cost of polycarbonate is usually lower because the unit price of silicone raw materials is significantly higher than that of polycarbonate. However, in small-batch production or for products with extremely complex shapes, the cost of molds for silicone may be lower, bringing the total cost into balance. You can make a choice based on your production method and scale.

Tactile and Aesthetic Properties

• Silicone is soft in texture, warm and smooth to the touch, skin-friendly, and available in a variety of colors/textures to choose from.
• Polycarbonate is cooler and harder to the touch, has a glossy surface, and can also be made into various textures.
• Comparison: Silicone excels in “touch”, while PC excels in “appearance”.

What are the Areas of Applicable for Silicone and Polycarbonate?

Silicone:

• Kitchenware/Baking Tools: Silicone spatulas, silicone molds, water cup sealing rings.
• Baby Products: Pacifiers, baby bottle straws, tableware.
• Medical and Health Products: Implants (such as breast augmentation implants), catheters, scar patches.
• Electronic Products: Phone cases, protective covers, keyboard protective films.
• Adult Products
• Industrial Parts: Various sealing rings, shock-absorbing components.

Polycarbonate:

• Electronic Appliances and Digital Products: mobile phone / tablet cases, laptop cases, optical lenses, LED lampshades, Blu-ray discs.
• Optics and Lighting: resin lenses, car headlight covers, explosion-proof shields, safety masks.
• Building Materials and Lighting: polycarbonate sheets, solid sheets (used for the wavy or solid panels of sports stadium roofs, carports, and greenhouse sheds).
• Medical Devices: hemodialysis machines, handles of surgical instruments.
• Food Contact: water bottles, travel mugs, baby pacifiers (please check for the “BPA-Free” label).
• Automotive Industry: car lights, instrument panels, car windows.
• Security Field: bulletproof glass for bank counters, prison doors and windows.

How to Choose the Appropriate Material According to Your Needs?

● Clarify Core Requirements

This is the most basic decision point, directly distinguishing between two major material families.

1. If your requirements are flexibility, elasticity, sealing, compression deformation, and soft touch → silicone
2. If your requirements are hardness, structural support, impact resistance, high rigidity and dimensional stability → polycarbonate

● Examine Environmental and Safety Requirements

This will determine whether the material is “appropriate”.

1. Does it come into contact with food, the mouth, or need to be implanted in the human body?

Yes → Prioritize medical/food-grade silicone

2. What is the temperature range of the working environment?

Long-term above 130℃ or below -30℃ → Prioritize silicone

3. Is it exposed to the outdoors or ultraviolet rays for a long time?

Yes → Choose UV-stabilized modified polycarbonate or anti-aging silicone

● Evaluate Optical and Aesthetic Requirements

This will determine the “expressiveness” of the product.

1. Is extremely high transparency or complex optical performance required?

Yes → Prioritize polycarbonate.

2. Do you pursue a skin-friendly, soft and warm touch?

Yes → Prioritize silicone.

● Consider Manufacturing and Cost

This will determine the “viability” of the option.

1. How about the product output and budget?

Large volume (over tens of thousands of pieces), sensitive to unit price

→ Polycarbonate has a greater cost advantage.

2. Is the design form exceedingly complex or does it contain embedded components?

Yes → Liquid Silicone Rubber (LSR) injection molding may be more suitable.

FAQ

Why is Polycarbonate More Cost-Effective than Silicone When Both are Mass-Produced?

Because polycarbonate is suitable for high-speed injection molding, its unit cost is highly competitive in large-scale production. In contrast, the vulcanization molding cycle of silicone is usually longer, so polycarbonate has a greater cost advantage.

Why is it Necessary to Have Physical Samples Made After Placing Bulk Orders for Products?

Physical prototypes can help you validate:

• Real texture and assembly
• Color difference and transparency
• Long-term performance tests

How to Choose Between Silicone and Polycarbonate at Different Temperatures?

When it comes to high-temperature disinfection, areas around car engines, and high-temperature sealing of LEDs, silicone is the only option; within the range of room temperature to 100℃, PC is a cost-effective choice.

What are the Main Disadvantages of Polycarbonate?

• Low Scratch Resistance: The surface hardness is relatively low, making it prone to scratches from hard objects. Therefore, many products undergo hard coating treatment.
• Average Chemical Resistance: It is not resistant to strong acids, strong alkalis, amines, ketones, and some organic solvents.
• Susceptible to UV Aging: Long-term exposure to sunlight causes yellowing and brittleness. Thus, UV stabilizers need to be added for outdoor use.
• Poor Resistance to Hydrolysis: Performance deteriorates in long-term high-temperature and high-humidity environments.

One of the Major Controversies Surrounding Polycarbonate: What is BPA?

BPA(Bisphenol A) is a key monomer raw material for synthesizing polycarbonate. However, under high temperatures, during cleaning or due to wear and tear, trace amounts of BPA may leach out from the material. BPA is considered an endocrine disruptor and may have potential impacts on health, especially on the development of infants and young children. Therefore, many countries and regions have banned the use of polycarbonate containing BPA in sensitive products such as baby bottles. When choosing products related to food or infants, simply look for the “BPA-Free” label.

Final thoughts

Silicone is an expert in flexibility, biocompatibility and temperature resistance, while PC is an expert in rigidity, optics and strength. Silicone and polycarbonate are not in a substitution relationship but rather complement each other. We hope you can make the wisest material choice based on the essential needs of your product. Legensilico has 20 years of experience in the silicone manufacturing industry and specializes in producing various silicone products. If you need any assistance, please feel free to contact us!