After the overview of BOPP films, do you have a rough ungerstanding of this ubiquitous material? In this blog, we will deepen our insights to its pros and cons, thus better targeting costumers' needs.
What is BOPP Film
Biaxially Oriented Polypropylene (BOPP) film has revolutionized the packaging industry since its introduction in the 1970s. This innovative material, stretched both mechanically and manually using cross-direction techniques, offers a unique combination of properties that have made it indispensable in various applications.
Key characteristics of BOPP
Colorless and odorless nature
Non-toxic composition
Balanced rigidity and toughness
Impressive impact resistance
High tensile strength (typical values range from 130-300 MPa)
Exceptional transparency (up to 90% light transmission)
These properties have positioned BOPP as a versatile material across multiple industries, from food packaging to textile lamination.
Advantages of BOPP Film
Physical Properties
BOPP excels in strength and durability, with a tensile strength that can reach up to 300 MPa in the machine direction. Its crystal-clear appearance, with light transmission rates of up to 90%, enhances product visibility on store shelves. The film's dimensional stability ensures consistent performance across various applications, with typical shrinkage rates below 4% at 130°C.
Resistance to punctures and flex cracks makes BOPP ideal for protective packaging. For instance, a 20-micron BOPP film can withstand up to 130 g/25 μm in dart impact tests, demonstrating its robustness in real-world applications.
Chemical Properties
BOPP acts as a formidable barrier against moisture， pollution, and harmful chemicals. Its water vapor transmission rate (WVTR) can be as low as 4-5 g/m²/day at 38°C and 90% relative humidity, making it an excellent choice for moisture-sensitive products.
The film's oil and grease resistance, with typical values exceeding 7 on the Kit test scale, further broadens its applicability. These properties make BOPP an excellent choice for food packaging and industrial uses, where product protection is paramount.
Environmental Benefits
In today's eco-conscious world, BOPP shines with its environmental credentials:
Recyclability: BOPP falls under recycling code #5 (PP), making it widely recyclable.
Lightweight: Typical densities around 0.90-0.92 g/cm³ contribute to reduced transportation emissions.
Energy-efficient production: The manufacturing process consumes less energy compared to some alternative materials.
A life cycle assessment study conducted by the European Polypropylene Film Manufacturers Association found that BOPP films have a 40% lower carbon footprint compared to equivalent PET films.
Economic Advantages
BOPP offers significant cost benefits due to its high yield. Its density of approximately 0.90-0.92 g/cm³ results in more film per unit weight compared to alternatives like polyester (density ~1.4 g/cm³). This translates to cost savings in both material usage and transportation.
Global acceptance facilitates easier international trade and shipping. According to industry reports, the Asia-Pacific region dominates the BOPP market, accounting for over 60% of global production capacity.
Versatility
BOPP's versatility is evident in its range of available finishes:
| Finish Type | Typical Gloss Units (45°) | Common Applications |
| High Gloss | >90 | Luxury packaging |
| Standard | 70-90 | General purpose |
| Matte | <40 | Non-glare labels |
| Silky | 40-70 | Soft-touch effects |
This variety caters to diverse aesthetic and functional needs across industries, from food packaging to high-end cosmetics.
Performance Benefits
BOPP excels in various performance aspects:
| Performance Aspect | Benefit | Typical Values |
| Printing Speed | High | Up to 300 m/min |
| UV Resistance | Excellent | <5% yellowing after 1000 hours |
| Electrostatic Charge | Low | <2 kV surface resistivity |
These attributes make BOPP ideal for high-speed production environments and outdoor applications.
Disadvantages of BOPP Film
Sealing Issues
BOPP's poor sealing properties can be problematic in certain packaging applications. Typical heat seal strengths range from 200-400 g/25 mm, which is lower compared to some alternative films. This limitation often requires additional treatments or coatings to improve sealability, potentially increasing production costs.
Surface Energy Concerns
Low surface energy (typically 29-31 mN/m) leads to challenges in ink adhesion. This results in potentially poor print quality, necessitating surface treatments before printing processes. Corona treatment can increase surface energy to 38-42 mN/m, but this effect diminishes over time.
Crystalline Nature
BOPP's high crystalline structure (typically 60-70% crystallinity) can cause:
These issues may affect the film's appearance and performance in specific applications, particularly where optical clarity is crucial.
Static Electricity
High-speed production often generates static electricity in BOPP films, with surface resistivity potentially reaching 10¹⁶ Ω/sq. This necessitates implementing static removal processes during manufacturing, adding complexity and cost to production lines.
Applications of BOPP Film
Packaging Industry
BOPP dominates food packaging due to its excellent barrier properties and clarity. It's used for:
The global food packaging film market, largely driven by BOPP, was valued at $37.5 billion in 2020 and is expected to reach $53.9 billion by 2026.
Printing and Lamination
The film excels in various printing applications:
| Application | Market Share | Growth Rate (CAGR) |
| Textbook covers | 15% | 4.5% |
| Magazine wraps | 20% | 3.8% |
| Product labels | 25% | 5.2% |
Specialty Uses
BOPP finds unique applications in:
Electrical insulation (dielectric strength: 200-300 kV/mm)
Adhesive tapes (peel adhesion: 15-20 N/25mm)
Flower packaging (moisture vapor transmission rate: 4-5 g/m²/day)
Its versatility continues to open new markets, with the specialty BOPP film segment growing at a CAGR of 7.2%.
Enhancements and Modifications
To overcome limitations, BOPP undergoes various treatments:
Corona treatment: Increases surface energy to 38-42 mN/m
Plasma treatment: Achieves surface energies up to 50 mN/m
Topcoatings: Improves printability and sealability
These processes improve bonding characteristics and overall performance, with treated films showing up to 50% improvement in ink adhesion.
Multi-layer composites combine BOPP with materials like PE, PO, PT, and LDPE. This results in enhanced properties:
| Property | Improvement |
| Temperature resistance | Up to 140°C (from 120°C) |
| Moisture barrier | WVTR reduced by 50% |
| Gas impermeability | O₂ transmission rate <10 cc/m²/day |
Comparison with Other Films
BOPP outperforms many alternatives:
| Aspect | BOPP | PET | LDPE |
| Yield (m²/kg at 25μm) | 44.4 | 28.6 | 42.6 |
| Cost (relative) | 1.0 | 1.2 | 0.9 |
| Transparency (% light transmission) | 90-92 | 88-90 | 88-90 |
| Moisture Barrier (g/m²/day at 38°C, 90% RH) | 4-5 | 15-20 | 12-15 |
This comparison highlights BOPP's competitive edge in the film market, particularly in terms of yield and moisture barrier properties.
Conclusion
BOPP film presents a compelling package of benefits despite some drawbacks. Its versatility, cost-effectiveness, and environmental friendliness position it as a leading choice in packaging and beyond. The global BOPP market is expected to grow at a CAGR of 6.9% from 2021 to 2026, indicating strong industry confidence in its future.
Ongoing research and development promise to address current limitations, potentially expanding BOPP's applications further. Innovations in nanotechnology and bio-based polypropylene are likely to enhance BOPP's properties and overcome existing challenges.
Having difficulty choosing the proper BOPP film for your projects? We're here to assist. Our specialists are ready to offer the advice and support you need to select the perfect material for any task. Contact us to achieve success!
FAQs
1. What are the main advantages of BOPP film?
Answer: BOPP film offers excellent clarity, high tensile strength, good moisture barrier properties, and cost-effectiveness. It's also lightweight, recyclable, and versatile in its applications.
2. What industries primarily use BOPP film?
Answer: BOPP film is widely used in:
3. How does BOPP film compare to other packaging materials in terms of environmental impact?
Answer: BOPP film has a lower carbon footprint compared to PET films and is recyclable. Its lightweight nature also contributes to reduced transportation emissions. However, like all plastics, improper disposal can lead to environmental issues.
4. What are the main drawbacks of using BOPP film?
Answer: The primary disadvantages include:
Poor heat sealing properties
Low surface energy, leading to printing challenges
Potential for static electricity build-up
Limited high-temperature resistance
5. Can BOPP film be used for food packaging?
Answer: Yes, BOPP film is widely used in food packaging due to its excellent moisture barrier properties, clarity, and inert nature. It's particularly popular for snack foods, confectionery, and fresh produce packaging.
6. How does BOPP film perform in terms of printability?
Answer: Untreated BOPP film has poor printability due to its low surface energy. However, surface treatments like corona discharge or the application of coatings can significantly improve its print receptivity.
7. Is BOPP film cost-effective compared to alternatives?
Answer: Generally, yes. BOPP film offers a good balance of performance and cost. Its low density results in more film per unit weight compared to alternatives like PET, potentially leading to cost savings in material usage and transportation.
