BoPET Film Market Growth: Why PET Resin Choice Matters

BoPET on the Rise: Structure and Strengths

Depending on the stretching method, polyester films are classified into uniaxially oriented polyester films (CPET) and BoPET. CPET typically uses semi-matte resin and undergoes drying, melting, extrusion, and longitudinal stretching. It offers relatively lower performance and cost, making it suitable for applications with modest requirements.

In contrast, BoPET is produced from high-transparency, glossy resin and is stretched both longitudinally and transversely. This biaxial orientation results in a more orderly and uniform arrangement of polyester molecular chains, significantly enhancing mechanical strength, thermal stability, dimensional stability, and gas barrier properties.

Made from high-transparency glossy PET chips, BoPET films boast excellent overall performance and have become the dominant product in the mid-to-high-end polyester film market, accounting for over 95% of market share. Performance varies by thickness: 

BoPET Film Market Outlook and Application Trends

Market research from MarketsandMarkets projects the global polyester film market to grow at a CAGR of about 6.5%, reaching over \$12 billion by 2028. BoPET films dominate this segment, accounting for more than 60% of the market.

Demand for high-barrier films in food packaging is increasing globally at 5% to 7% annually, driving BoPET's use in transparent composite and cooking films. Consumer focus on safety and sustainable packaging further boosts BoPET’s market acceptance due to its recyclability and compliance with international food safety standards.

The electronics and electrical sectors also offer strong growth potential. Advances in 5G, electric vehicles, and smart electronics are fueling demand for high-performance insulating films. The electronics film market grows at around 8% yearly, with BoPET's thermal and dimensional stability critical for capacitor, motor insulation, and transformer films. This segment is expected to see double-digit growth over the next five years.

In photovoltaics, PET films serve as the central base layer in solar cell backsheets, providing mechanical support, barrier properties, and electrical insulation, often enhanced with polymer coatings.

Environmental regulations are accelerating bio-based and modified PET film development, supporting BoPET's shift toward sustainable solutions. By 2030, bio-based BoPET is expected to exceed 15% of the market, revitalizing the polyester film industry.

Comparison of BoPET and Other Film Types

 BoPET films stand out for their superior mechanical strength, thermal stability, and dimensional stability, making them ideal for high-performance functional applications. While BoPET has relatively lower heat-sealing capabilities and higher production costs, its overall performance makes it indispensable in electronics, electrical insulation, and premium packaging markets. 

In comparison, BOPP and CPP films focus more on heat-sealability and cost-effectiveness, catering primarily to budget-conscious packaging needs. BOPA films excel in barrier properties and flexibility, making them suitable for flexible packaging solutions.

How to Choose PET Resin: A Performance-Driven Guide Based on Application Needs

The quality of BOPET films is closely related to the performance of the PET resin used. Selecting resin that aligns with specific application requirements is essential to help ensure consistent and reliable film quality. For example, packaging films often prioritize tensile strength and transparency, whereas electronic and insulation films require enhanced thermal stability and dielectric properties.

Key parameters to consider include:

• Intrinsic Viscosity ([η]): Indicates molecular weight and influences melt flow and mechanical strength. The typical range for film-grade resin is 0.60–0.68 dl/g, with some high-end applications requiring up to 0.80 dl/g. Values outside this range may affect processability or film properties.

• Carboxyl End Group Content ([COOH]): Recommended to be maintained between 25–40 mmol/kg to support thermal stability and electrical performance. Higher levels may adversely affect these properties.

• Diethylene Glycol Content (DEG): While DEG aids processing by lowering melting point and increasing chain flexibility, excessive amounts can compromise thermal stability and aging resistance. Typical limits are ≤1.2% for general films and ≤1.0% for specialized insulation films.

• Ash Content: Ideally kept at or below 0.05% for clear chips to avoid negative impacts on crystallinity and film formation.

• Moisture Content: Should be controlled at ≤0.4% to prevent hydrolytic degradation, which can lead to reduced molecular weight, defects, and discoloration during processing.

WK-631 Ultra-Bright Polyester Chips — Premium Raw Material for BOPET Films and Polyester Filaments

WK-631 is a specially formulated ultra-bright PET resin chip designed for high-performance BOPET films and polyester filament applications. It delivers excellent color clarity, low impurity content, stable molecular weight distribution, and superior processability.

Trusted by customers for its outstanding performance and consistency, WK-631 meets critical demands including stable physical properties, processing adaptability, product clarity and color, high production yield, and strict regulatory compliance.

• The intrinsic viscosity of 0.645±0.010 dL/g strikes an optimal balance between melt flow and mechanical strength, enabling uniform molecular orientation during biaxial stretching, which enhances film toughness and strength while reducing production variability.

• Controlled carboxyl end group content (26±4 mmol/kg) ensures excellent thermal stability and electrical insulation, making it ideal for electronic and electrical films such as capacitor, motor, and transformer applications.

• DEG content at 0.9±0.15% optimizes melting behavior and crystallization rate, promoting stable and efficient processing while minimizing thermal degradation, thus ensuring consistent film quality.

• Low moisture content (≤0.40%) and minimal impurities reduce bubble formation and defects during extrusion, improving film formation and yield, ultimately lowering waste and production costs.

• Certified by Japan's JCII under the 1988 Food Sanitation Act (No. 233) and compliant with voluntary safety standards, WK-631 is suitable for food packaging, pharmaceuticals, and other hygiene-sensitive applications, facilitating global market access.

• The color value (b value) of 0.5±2 offers superior transparency and gloss, meeting stringent aesthetic requirements for premium printed, label, and coated films, enhancing product value and market competitiveness.

Conclusion

BoPET films, renowned for their outstanding performance and wide-ranging applications, are driving rapid growth in the polyester film market. Selecting high-quality PET resins tailored to specific application requirements is crucial to ensuring product quality and processing stability. With ongoing technological innovation and a shift toward sustainability, BoPET is set to unlock significant growth potential across packaging, electronics, electrical insulation, and renewable energy sectors, supporting industry advancement and sustainable development.