High‑Temperature Insulation Film Testing Service – Performance Verification for Thermal and Electrical Insulation in Extreme Environments
At zhongxi testing, we provide specialized high‑temperature insulation film testing services for aerospace, automotive, electronics, power generation, and petrochemical industries in Bahrain. High‑temperature insulation films – including polyimide (Kapton), silicone rubber, mica, ceramic fiber, and PTFE based materials – are critical for protecting components in environments where temperatures exceed 200°C. Our ISO/IEC 17025 accredited laboratory performs comprehensive testing – including thermal stability (thermogravimetric analysis – TGA), thermal shrinkage, dielectric strength, insulation resistance, tensile strength, elongation, flame retardancy, and chemical resistance – to ensure compliance with international standards (ASTM D5213, ISO 527, IEC 60243, UL 94) and Bahraini industrial safety requirements.
Types of High‑Temperature Insulation Film Samples We Test
Our laboratory handles a wide range of high‑temperature insulation materials used across Bahrain’s energy and manufacturing sectors:
- Polyimide (Kapton) films – continuous operating temperature up to 260°C
- PTFE (Teflon) films – up to 200°C continuous, 250°C peak
- Silicone rubber films – up to 200°C (300°C for specialty grades)
- Mica-based insulation films – up to 600°C (for furnace and fire‑resistant applications)
- Ceramic fiber insulation films – up to 1000°C
- Polyesterimide and polyamideimide films – up to 200°C
- Glass cloth reinforced silicone rubber films – up to 220°C
- Multi‑layer composite films (polyimide + adhesive + silicone coating)
- New production batches (incoming quality assurance for manufacturers and suppliers)
- In‑service insulation films removed from equipment (degradation and residual life assessment)
- Competitor product benchmarking (thermal stability and electrical performance)
Key Testing Parameters and Methods for High‑Temperature Insulation Films
1. Thickness Uniformity – ASTM D5213 / ISO 4593
The primary parameter in high‑temperature insulation film testing is thickness consistency. Using a digital micrometer (accuracy ±0.001 mm), we measure thickness at 10 points across the film width and length. For polyimide films (0.025–0.125 mm nominal), acceptable tolerance is ±5%; for thicker silicone or mica films, ±10% is acceptable. Variation beyond these limits can cause uneven electrical breakdown strength and poor adhesion to substrates.
2. Thermal Stability (Thermogravimetric Analysis – TGA) – ASTM E1131 / ISO 11358
We heat a 5–10 mg sample from 25°C to 800°C at 10°C/min under nitrogen and air atmospheres. The decomposition temperature (Td, 5% weight loss) is recorded. For polyimide films, Td is typically 500–550°C; for silicone rubber, 380–420°C; for PTFE, 480–500°C. A Td lower than the specification by > 30°C indicates poor polymer quality or contamination.
3. Thermal Shrinkage – ASTM D1204 / ISO 11501
We mark a 200 mm length on the film specimen and place it in an oven at the specified operating temperature (e.g., 200°C, 250°C, 300°C) for 30 minutes. After cooling, we re‑measure the length. Thermal shrinkage (%) = (initial length – final length) / initial length × 100%. For polyimide films, shrinkage should be < 0.5%; for silicone rubber, < 2%; for PTFE, < 3%. Excessive shrinkage (> 5%) causes wrinkling and delamination.
4. Dielectric Strength (Breakdown Voltage) – ASTM D149 / IEC 60243
We place the film specimen between two 25 mm diameter brass electrodes in a dielectric oil bath (to prevent flashover) and apply an AC voltage at 500 V/s until breakdown occurs. The dielectric strength (kV/mm) is calculated. For polyimide films, typical dielectric strength is 150–250 kV/mm; for silicone rubber, 20–40 kV/mm; for PTFE, 60–100 kV/mm. Values below 80% of the specification indicate porosity or contamination.
5. Insulation Resistance (Volume and Surface Resistivity) – ASTM D257 / IEC 60093
Using a three‑electrode system, we apply 100 V, 250 V, or 500 V DC (depending on film thickness) and measure leakage current. Volume resistivity (Ω·cm) and surface resistivity (Ω/□) are calculated. For polyimide and PTFE, volume resistivity should be > 10¹⁴ Ω·cm; for silicone rubber, > 10¹² Ω·cm. Low resistivity (< 10¹⁰ Ω·cm) indicates moisture absorption or ionic contamination.
6. Tensile Strength and Elongation – ASTM D882 / ISO 527‑3
We cut 25 mm wide strips from the film (machine direction and transverse direction) and pull at a constant speed of 50 mm/min (or 250 mm/min for very thin films) using a universal testing machine. For 0.05 mm polyimide, typical tensile strength is 150–200 MPa, elongation is 30–60%. For silicone rubber films, tensile strength is typically 5–10 MPa, elongation is 200–600%. Low tensile strength (< 80% of spec) may indicate degraded polymer or inadequate curing.
7. Tear Resistance – ASTM D1004 / ISO 6383
Using a trouser or Graves tear specimen, we measure the force required to propagate a tear (N). For high‑temperature films used in wrapping and cable insulation, minimum tear resistance of 0.5 N (for thin films) to 5 N (for thicker sheets) is required. Low tear resistance leads to tearing during installation and service.
8. Flame Retardancy – UL 94 / IEC 60695‑11‑10
We test the film using the vertical burn method: a 20 mm flame is applied to the bottom edge of a vertical specimen for 10 seconds (twice). We record after‑flame time (s), after‑glow time (s), and observe dripping. For high‑temperature insulation materials used in aviation and electronics, UL 94 V‑0 (after‑flame < 10 s, no flaming drips) is typically required. Silicone rubber films often achieve V‑0; PTFE is inherently flame‑retardant (V‑0).
9. Chemical Resistance – ASTM D543 / ISO 175
We immerse film specimens in representative chemicals – jet fuel (Jet A‑1), hydraulic fluid (Skydrol), 5% H₂SO₄, 5% NaOH, and de‑ionized water – for 7 days at 23°C. After exposure, we measure weight change (%) and re‑test tensile strength. For polyimide, weight change should be < 0.5%; for silicone rubber, < 5%. Any softening, swelling, or loss of tensile strength > 20% is considered a failure.
10. Water Absorption – ASTM D570 / ISO 62
We dry the film at 105°C for 1 hour, weigh it, then immerse in distilled water at 23°C for 24 hours, blot, and re‑weigh. Water absorption (%) = (wet weight – dry weight) / dry weight × 100%. For high‑temperature films, water absorption should be < 0.5% (polyimide, PTFE) or < 2% (silicone rubber). High water absorption leads to reduced dielectric strength and dimensional changes.
Quality Grading and Acceptance Criteria
Based on our high‑temperature insulation film testing, we classify films into three grades (clients provide specific acceptance criteria for their application):
- Grade A (Premium – Aerospace and High‑Voltage) – Thickness tolerance ±3%, Td ≥ 520°C, thermal shrinkage < 0.3%, dielectric strength ≥ 200 kV/mm, tensile strength ≥ 95% of spec, UL 94 V‑0, water absorption < 0.2%.
- Grade B (Standard – General Industrial) – Thickness tolerance ±5%, Td ≥ 480°C, thermal shrinkage < 1%, dielectric strength ≥ 150 kV/mm, tensile strength ≥ 85% of spec, UL 94 V‑1, water absorption < 0.5%.
- Grade C (Reject – Not Suitable) – Thickness tolerance > ±10%, Td < 400°C, visible shrinkage after 30 minutes, dielectric strength < 80 kV/mm, tensile strength < 50% of spec, fails flame test – immediate batch rejection.
Reporting and Deliverables
Our high‑temperature insulation film testing report includes: sample identification (material type, nominal thickness, batch number, manufacturer), thickness map (min, max, average), TGA thermogram (decomposition temperature), thermal shrinkage (%), dielectric strength (kV/mm), insulation resistance (Ω·cm), tensile strength and elongation, tear resistance, flame retardancy rating, chemical resistance data (weight change, tensile retention), water absorption, and a clear pass/fail conclusion based on client‑supplied criteria. Raw data (TGA curves, electrical breakdown logs, stress‑strain curves) are archived for 10 years.
In summary, a thorough high‑temperature insulation film testing service from zhongxi testing ensures that your insulation materials withstand extreme thermal, electrical, and chemical stresses in Bahrain’s power, oil, and manufacturing industries. Contact our laboratory to schedule batch testing for your next insulation film procurement or to verify in‑service material condition.
Applications in the Bahraini Industry
- Petrochemical plants (Sitra, Bapco): Insulation for cables, pipes, and equipment near furnaces and reactors.
- Power generation and desalination (Al Hidd, Durrat Al Bahrain): High‑temperature cable and busbar insulation.
- Aerospace and defence (Bahrain International Airport, military bases): Insulation for aircraft wiring and avionics.
- Electronics manufacturing: Flexible PCB insulation and thermal management.
- Medical device sterilization: High‑temperature film for autoclave‑resistant packaging.
