Improper material selection risks premature yellowing, cracking, or excessive costs. Plexiglass (also called acrylic or PMMA) and Polycarbonate (PC, such as Lexan or Makrolon) are leading choices for transparent parts, each addressing distinct performance needs. As a supplier of factory-sourced plastic pellets, Sales Plastics helps manufacturers choose the right resin for injection molding, extrusion, or other processes to optimize performance and cost.
Material and Technical Compariso
Acrylic and polycarbonate pellets are available in 25kg bags or ton bags for injection molding and extrusion, producing parts like glazing, housings, and optical components. The choice of resin hinges on mechanical properties, processing compatibility, and budget constraints. Below are the key characteristics of each material.
Polycarbonate (PC)
- Key Properties: Impact resistance up to 250 times that of glass, high heat tolerance (up to 140°C), and flexibility for repeated bending. Density ~1.2 g/cm³; tensile strength ~65 MPa.
- Pellet Characteristics: Supplied in 25kg bags or ton bags, with melt flow indices of 5-20 g/10 min. Requires drying at 120°C for 4 hours to prevent moisture-induced defects like bubbles in injection molding.
- Advantages: Ideal for high-impact, high-temperature applications; supports cold-forming for on-site adjustments.
Acrylic (PMMA)
- Key Properties: ≥92% light transmission for superior clarity, inherent UV stability, and excellent machinability. Density ~1.18 g/cm³; tensile strength ~70 MPa.
- Pellet Characteristics: Available in 25kg bags, with melt flow indices of 1-10 g/10 min. Dries at 80°C for 2-3 hours, minimizing energy costs.
- Advantages: Cost-effective (15-40% less than PC), easy to cut and polish, suited for optical applications.
| Property | Acrylic (PMMA) | Polycarbonate (PC) | Practical Implications |
|---|---|---|---|
| Impact Strength | ~17× glass | ~250× glass | PC suits safety glazing; acrylic handles light impacts. |
| Heat-Deflection Temperature (66 psi) | ~90°C / 195°F | ~140°C / 280°F | PC endures hot environments; acrylic fits ambient use. |
| Scratch Resistance | Higher | Lower (unless hard-coated) | Acrylic maintains gloss; PC needs coatings for wear. |
| UV Durability | Good; may haze after 8-10 years | Excellent with UV-stabilized grades | UV-stabilized PC or cast acrylic for outdoor exposure. |
| Formability | Bonds with solvent cements; thermoforms but cracks if bent cold | Cold-bends and thermoforms without crazing | PC allows on-site bending; acrylic suits precise cuts. |
| Cost (per kg of pellets) | 15-40% less than PC | Higher | Acrylic reduces costs for non-critical parts. |
| Recyclability | Easier; mechanically recyclable | More complex; requires specialized processes | Acrylic supports sustainable practices. |
Common Applications in Manufacturing
Polycarbonate Applications
- Machine Guards and Shields: Molded from pellets into sheets for production lines, meeting OSHA standards. Example: CNC machine guards resisting tool impacts.
- Security Glazing: Formed into panels for ATMs or transit shelters, absorbing high-energy impacts. Example: Bullet-resistant bank windows.
- Electronic Housings: Injection-molded from granules for UL94 V-0 compliant enclosures. Example: Laptop casings with dimensional stability.
- Greenhouse Panels: Extruded into UV-stabilized multi-wall sheets for awnings. Example: Commercial greenhouse roofing lasting 10+ years.
- Tubes and Guards: Processed into transparent tubes for pneumatic systems. Example: Protective sleeves for wiring in automation.
- 3D Printer Filament: Extruded from pellets for durable prototypes. Example: Heat-resistant brackets for automotive testing.
Acrylic Applications
- Retail Displays and Signage: Extruded and polished into high-clarity POS displays. Example: Supermarket menu boards with vibrant graphics.
- Architectural Glazing: Formed into skylights or partitions for light transmission. Example: Office dividers with 92% clarity.
- Protective Covers: Used for museum cases or sneeze guards. Example: Artifact displays requiring scratch resistance.
- Lighting Diffusers: Molded into LED panels for uniform light. Example: Retail lightboxes with consistent illumination.
Key Factors for Material Selection
1. What loads will the part face?
- For high-impact scenarios like hammer blows, PC is essential; for minor handling stresses, acrylic reduces costs.
2. What are the temperature and chemical exposures?
- Acrylic excels in clarity and gloss for displays or lenses.
3. How critical are optics and finish?
- Acrylic: Superior clarity and surface gloss, making it ideal for displays, lenses, and aesthetic parts.
- PC: Good transparency, but less optical brilliance than acrylic.
4. What are the processing requirements?
- Acrylic supports clean laser cutting; PC requires CNC or cold-sawing to avoid fumes.
5. How do budget and durability align?
- Test samples from Sales Plastics for drop or yellowing performance; consider FDA-compliant grades for food-contact applications.
FAQ About Plexiglass vs Polycarbonate
A: In impact and flexural fatigue, yes. However, acrylic actually has the higher tensile modulus, so it can feel “stiffer” in thin gauges.
A: Un‑stabilised PC will yellow first. UV‑grade PC or cast acrylic rated for outdoor use both stay clear for a decade or more.
A: Plexiglass cuts cleanly with a CO₂ laser; polycarbonate discolours and releases toxic fumes—use CNC or cold‑saw methods instead.
A: Specify a hard‑coated sheet or apply a dip‑coat after machining; this adds 2–5 % to cost but extends life in high‑traffic areas.
A:Lexan, a polycarbonate, offers greater impact resistance and durability compared to acrylic, which is lighter but more prone to scratching.
A:Plexiglass is a brand of acrylic. Both are the same material—PMMA—offering high clarity and stiffness but lower impact resistance compared to polycarbonate.
A:Yes, Lexan is a specific brand of polycarbonate, recognized for its robust and clear properties as a plastic raw material.
A:Polycarbonate is tougher, with superior impact and flexural fatigue resistance. Perspex, a brand of acrylic, is stiffer due to a higher tensile modulus and clearer but more prone to scratching and cracking.
Conclusion
- Choose Polycarbonate for applications that demand maximum impact strength, superior heat resistance, and cold-forming flexibility.
- Choose Plexiglass (Acrylic) when you need pristine optical clarity, a scratch-resistant finish, and maximum budget efficiency.
Still unsure which material is right for your project? The technical team at SalesPlastics is here to help. Contact us to learn more about our Plexiglass and Polycarbonate products.
Email:jerry@salesplastics.com
Phone:+8618657312116
