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Which Tape is Better: PET or PI for Circuit Board Masking? |https://www.lvmeikapton.com/

Source: | Author:Koko Chan | Published time: 2025-04-18 | 9 Views | Share:

Which Tape is Better: PET or PI for Circuit Board Masking?

IntroductionCircuit board masking plays a crucial role in protecting sensitive components during manufacturing processes like etching, soldering, and cleaning. Selecting the right masking tape is vital to ensure precision, reliability, and longevity. Among various materials, Polyethylene Terephthalate (PET) and Polyimide (PI) are widely used due to their unique properties. This article aims to compare PET and PI tapes comprehensively, exploring their mechanical, thermal, electrical, chemical, and cost-related aspects to help engineers make informed decisions.

1. Performance Comparison1.1 Mechanical PropertiesPET tape excels in tensile strength and flexibility, making it suitable for general-purpose applications. It offers good resistance to abrasion and mechanical stress, but its tear resistance is compromised when subjected to double-edged cutting, prone to splitting. On the other hand, PI tape demonstrates superior mechanical robustness, boasting high tensile strength and excellent dimensional stability. It withstands repeated stretching and bending without deformation, ideal for applications requiring durability and long-term reliability.

Table 1: Mechanical Properties Comparison

Property	PET Tape	PI Tape
Tensile Strength	High	Extremely High
Tear Resistance	Moderate (Prone to Splitting)	Excellent
Flexibility	Good	Outstanding
Dimensional Stability	Fair	Exceptional

1.2 Thermal PerformanceThermal resistance is a critical factor in circuit board masking. PET tape can withstand temperatures up to 130°C, suitable for most soldering and etching processes. However, its performance may degrade beyond this limit. PI tape, renowned for its exceptional heat resistance, can endure continuous exposure to 180°C and short-term exposure to 200°C. This makes PI ideal for high-temperature processes like lead-free soldering (260°C) and aerospace applications.

1.3 Electrical PropertiesBoth PET and PI exhibit excellent electrical insulation. PET has a breakdown voltage of ≈6.6 kV, sufficient for most consumer electronics. PI surpasses PET with a breakdown voltage of up to 20 kV, ensuring safety in high-voltage environments. Additionally, PI's low dielectric constant and loss tangent make it suitable for high-frequency applications.

1.4 Chemical ResistancePET tape offers resistance to acids, solvents, and organic chemicals but is susceptible to degradation in strong alkali environments. PI, with its robust chemical inertness, withstands even aggressive chemicals like浓硝酸 and浓硫酸. This resilience makes PI tapes ideal for corrosive environments, such as chemical processing equipment.

1.5 Optical and Surface PropertiesPET tape is highly transparent, allowing for easy visual inspection during assembly. Its smooth surface facilitates precise alignment. PI tape, while less transparent, provides superior moisture and gas barrier properties, crucial for humidity-sensitive applications.

Table 2: Key Performance Summary

Property	PET Tape	PI Tape
Thermal Resistance	Up to 130°C	Up to 180°C (Continuous) / 200°C (Short-term)
Chemical Resistance	Acid, Solvent-Resistant (Weak Alkali-Susceptible)	Strong Acid/Alkali-Resistant
Electrical Insulation	≈6.6 kV Breakdown Voltage	≈20 kV Breakdown Voltage
Transparency	High	Opaque (Foggy)
Moisture Barrier	Moderate	Excellent

2. Application Considerations2.1 Cost vs. PerformancePET tape offers a cost-effective solution for applications with moderate thermal and chemical requirements. Its affordability makes it prevalent in consumer electronics, automotive interiors, and general industrial masking. PI tape, priced several times higher than PET, is justified in high-performance applications demanding extreme thermal stability, chemical resistance, and electrical reliability. Industries like aerospace, medical equipment, and military electronics prioritize PI for its longevity and safety.

2.2 Manufacturing ProcessesPET tape's lower melting point (≈160-170°C) risks deformation during high-temperature processes. Its weak adhesion to non-polar surfaces (e.g., PP) may require surface treatment. PI tape, with a higher melting point and superior adhesion, excels in processes like laser direct structuring (LDS) and plasma etching.

2.3 Environmental FactorsPI tape's non-stick surface (e.g., Teflon-coated variants) enhances ease of removal without residue, crucial for cleanroom environments. PET tape may generate static electricity, posing risks to sensitive components. However, PET is more environmentally friendly, recyclable, and has lower production emissions than PI.

3. Advantages and DisadvantagesPET TapeAdvantages:

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Cost-effective

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High transparency

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Good mechanical strength

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Easy to handle and process

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Widely available

Disadvantages:

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Limited thermal resistance

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Prone to tearing during cutting

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Static electricity issues

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Susceptible to strong alkalis

PI TapeAdvantages:

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Exceptional thermal and chemical resistance

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Ultra-high electrical insulation

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Dimensionally stable

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Long-term reliability in harsh environments

Disadvantages:

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High cost

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Less transparent

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Complex manufacturing process

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Environmental concerns (limited recyclability)

4. Case Studies4.1 Automotive ElectronicsIn automotive engine control units (ECUs), PI tape is preferred due to exposure to high temperatures (up to 150°C) and engine oils. PET tape may degrade, risking short circuits.

4.2 Aerospace ApplicationsPI tape's resistance to cosmic radiation, thermal cycling (-70°C to 200°C), and chemical exposure makes it indispensable for satellite and spacecraft circuit boards.

4.3 Consumer ElectronicsPET tape suffices for smartphones and laptops, balancing cost and performance. However, PI tape is used in high-end devices like military-grade ruggedized tablets.

5. Future Trends and InnovationsResearch is focusing on:

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Developing PI variants with improved processability and lower costs

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Enhancing PET's thermal stability through polymer blending

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Hybrid tapes combining PET and PI properties

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Bio-based PI materials for sustainability

6. ConclusionThe choice between PET and PI tape depends on application-specific requirements. For cost-sensitive, moderate-temperature applications (e.g., consumer electronics), PET tape offers a practical solution. In contrast, PI tape's unparalleled thermal, chemical, and electrical performance makes it the superior choice for mission-critical environments like aerospace, medical devices, and automotive electronics. Engineers must weigh factors like process temperatures, chemical exposure, budget constraints, and long-term reliability to determine the optimal material.

References

Lvmei Kapton. (n.d.). Which Tape is Better: PET or PI for Circuit Board Masking? Retrieved from

Smith, J. (2023). Advanced Materials for Electronic Packaging. Wiley.

IEEE Standard 1394-1995: High-Performance Serial Bus.