Expanded Polypropylene
Electrical insulation and separation with cushioning effect in communications and power cables
Expanded Polypropylene
Expanded polypropylene (PPF) is a mono-oriented film with a closed-cell structure that combines electrical insulation properties with a mechanical cushioning effect. Its reduced density of 0.52 g/cm³ — roughly half that of compact polypropylene — provides meaningful thickness with low added weight, while the cellular structure delivers thermal-conductance resistance of 0.08 W/m·K that contributes to cable thermal insulation.
In communications, power and signal cable construction, PPF is used as electrical insulation, separator between components and bundling element. Its expanded structure absorbs dimensional irregularities between layers and provides a degree of compressibility that eases cable shaping without damaging internal components — especially relevant in cables with optical fibres or delicate conductors.
Thicknesses range from 80 to 300 µm with dielectric strength from ≥1.3 kV in the finest references up to ≥2.0 kV in the thicker ones. The specific resistance of 10¹⁵ Ω·cm provides very high-quality electrical insulation, while the relative permittivity ≥1.2–1.3 minimises dielectric losses in high-frequency applications.
Unlike compact polyester film, PPF offers a softer behaviour during taping: the cellular structure yields slightly under pressure, conforming to underlying irregularities without transferring marks or generating stress-concentration points. This is especially useful in cables where mechanical protection of inner components is a priority.
Compatibility with copper has been verified through ageing tests at 100°C for 7 days, with no perceptible deterioration of the material's physical properties. This stability ensures insulation integrity throughout the cable's service life, even under elevated temperatures.
How to choose the right one?
The right thickness depends on the balance between required insulation level, desired cushioning effect and available space in the construction. Thinner gauges offer greater flexibility, while thicker ones deliver greater mechanical protection and dielectric strength.
| Reference | Thickness | Weight | Dielectric strength | Tensile strength | Typical application | When to choose |
|---|---|---|---|---|---|---|
| PPF 80 | 80 µm | 43 g/m² | ≥1.3 kV | 90 N/mm² | Fine separation, signal cables | Maximum flexibility, tight spaces |
| PPF 90 | 90 µm | 48 g/m² | ≥1.3 kV | 90 N/mm² | Standard insulation | Flexibility/insulation balance |
| PPF 125 | 125 µm | 65 g/m² | ≥1.5 kV | 100 N/mm² | Telecom cables | Greater dielectric strength, general use |
| PPF 170 | 170 µm | 89 g/m² | ≥2.0 kV | 85 N/mm² | Power cables, bundling | Moderate cushioning effect |
| PPF 300 | 300 µm | 160 g/m² | ≥2.0 kV | 80 N/mm² | Maximum mechanical protection | Pronounced cushioning, fibre-optic protection |
Technical specifications
The values shown below come from tests run to DIN standards and characterise the material's behaviour both during processing and in service.
Mechanical properties
| Property | Test method | PPF 80 | PPF 90 | PPF 125 | PPF 170 | PPF 300 |
|---|---|---|---|---|---|---|
| Thickness (µm) | DIN 53370 | 80 | 90 | 125 | 170 | 300 |
| Thickness tolerance (%) | DIN 53370 | ±12 | ±12 | ±10 | ±10 | ±10 |
| Weight (g/m²) | DIN 53352 | 43 | 48 | 65 | 89 | 160 |
| Weight tolerance (%) | DIN 53352 | ±8 | ±8 | ±7 | ±7 | ±7 |
| Density (g/cm³) | DIN 53479 | 0.52 | 0.52 | 0.52 | 0.52 | 0.52 |
| Tensile strength (N/mm²) | DIN EN ISO 527-1 | 90 | 90 | 100 | 85 | 80 |
| Elongation at break (%) | DIN EN ISO 527-1 | 15 | 15 | 15 | 15 | 15 |
| Tensile strength at 5% elong. (N/mm²) | DIN EN ISO 527-1 | 35 | 35 | 40 | 30 | 25 |
| Shrinkage 100°C/10 min (%) | DIN 40634 | 3 | 3 | 3 | 3 | 3 |
Electrical properties
| Property | Test method | PPF 80 | PPF 90 | PPF 125 | PPF 170 | PPF 300 |
|---|---|---|---|---|---|---|
| Relative permittivity | DIN 53483 | ≥1.2 | ≥1.2 | ≥1.3 | ≥1.3 | ≥1.3 |
| Dielectric strength (kV) | DIN 53481 | ≥1.3 | ≥1.3 | ≥1.5 | ≥2.0 | ≥2.0 |
| Specific resistance (Ω·cm) | DIN 53482 | 10¹⁵ | 10¹⁵ | 10¹⁵ | 10¹⁵ | 10¹⁵ |
Thermal properties
| Property | Test method | Value |
|---|---|---|
| Thermal conductance resistance | DIN 52612 | 0.08 W/mK |
| Thermal shrinkage (100°C/10 min) | DIN 40634 | 3% |
| Resistance to copper contact | — | No perceptible deterioration after 7 days at 100°C |
Construction
| Component | Material |
|---|---|
| Base material | Polypropylene |
| Structure | Closed-cell, expanded |
| Orientation | Mono-oriented |
Values shown are typical and do not constitute binding specifications.
Available variants
Standard thicknesses
- 80, 90, 125, 170, 300 µm
Alternative materials by application
- Compact polyester film (PET) — when greater dielectric strength per thickness is required
- Non-woven polyester (NWP) — when easy stripping is required
- Compact polypropylene film (PP) — when no cushioning effect is required
Delivery formats
The supply format directly influences process continuity and taping efficiency. Material can be supplied in different formats and dimensions adapted to each machine type and production speed.
Pad / Roll (pancake)
Pancake format for taping lines
Spool (TWS / STS reel)
Reel for automatic taping lines
Other formats and dimensions available on request. Custom slitting service available.
Application sectors
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Our technical team is available to help you select the optimum material for your application.
Custom slitting
Up to 1200 mm width, ±0.50 mm tolerance
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Spooling
Pad to TWS/STS spool conversion
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Need technical advice?
Our technical team is available to help you select the optimal material for your application.
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