Solar Encapsulant · EPE Film
EPE Film for Encapsulating Solar Modules
The Film
Built for PID-Free Bifacial Modules
Saatvik SS-EPE UVT-F and SS-EPE UVC-B are highly transparent encapsulant films with excellent weather resistance, strong adhesion to glass and metal materials, and outstanding operational performance. These films enable shorter lamination cycles while maintaining high module efficiency.
The EPE-series provides a highly cost-effective encapsulant solution for PID-free requirements in both P-type and N-type bifacial PV modules. It can successfully withstand a 288-hour PID test under test conditions of 85°C, 85% RH, and 1500 VDC. In addition, EPE-series films exhibit excellent long-term durability and reliability.
Transmittance, 1100–380 nm
PID test at 85°C · 85% RH · 1500 VDC
Peel strength from glass
Volume resistivity, Ω·cm
EPE encapsulant combination
The material and structure of the EPE-series product: EVA · POE · EVA.
Product Specification
What the Film Delivers
High Transparency, Low Haze
High Gel Content
Low WVTR
Anti-PID
No Bubbling, No Cell Shifting, High Production Efficiency
High Volume Resistance
Characteristics
Main Characteristics
The main characteristics of Saatvik SS-EPE UVT-F & SS-EPE UVC-B film are as follows:
Excellent long-term resistance against PID (Potential Induced Degradation).
Superior durability under extreme weather, high temperature, and high humidity conditions.
Outstanding adhesion to glass, metal, and polymer back sheet, maintaining stable bonding over time.
High light transmittance and optical transparency for enhanced module efficiency.
Good manoeuvrability during lamination process, no slipping issue.
Strong UV resistance ensuring long operational life.
Choosing the Film
Two Grades, Matched to the Module
Both grades share the same EVA · POE · EVA structure and roll specification. They differ in how much ultraviolet light they pass — the 380–290 nm transmittance below — and in the module configurations they are recommended for.
Grade
SS-EPE UVT-F
For P-type or N-type PV modules, recommended as the encapsulant for glass-to-glass module configurations — and, with SS-EPE UVC-B, for glass-to-transparent backsheet configurations.
Grade
SS-EPE UVC-B
For P-type or N-type PV modules, recommended with SS-EPE UVT-F as the encapsulant for glass-to-transparent backsheet module configurations.
Specification
Roll Specification
Identical for SS-EPE UVT-F and SS-EPE UVC-B, in two gram-weight grades.
| Type | 380 g/m² grade | 560 g/m² grade |
|---|---|---|
| Gram weight & tolerance | (380 ± 20) g/m² | (560 ± 20) g/m² |
| Thickness & tolerance | 0.50 ± 0.10 mm | 0.65 ± 0.10 mm |
| Length per roll | 130 sqm ~ 350 sqm | 110 m ~ 290 m |
| Width tolerance | (0/+3) mm | (0/+3) mm |
| Surface structure | Orange peel / Diamond embossed | Orange peel / Diamond embossed |
The above specification values can be adjusted for customization.
General thickness specifications — the final apparent thickness should be determined by the embossed pattern.
Technical Data
Technical Specification
Swipe the table sideways for both grades →
| Property | Test method | Units | SS-EPE UVT-F | SS-EPE UVC-B |
|---|---|---|---|---|
| Optical Property | ||||
| Transmittance, 1100–380 nm | ASTM E 424 | % | ≥90.5 | ≥90.5 |
| Transmittance, 380–290 nm | ASTM E 424 | % | ≥80 | ≤30 |
| Physical Property | ||||
| Gel content | ASTM D 2765 | Gel% | 75 ≤ X ≤ 95 | 75 ≤ X ≤ 95 |
| Electrical Property | ||||
| Volume resistivity | ASTM D 257 | Ω·cm | ≥1.0 × 10¹⁵ | ≥1.0 × 10¹⁵ |
| Dielectric strength | ASTM D 149 | kV/mm | ≥25.0 | ≥25.0 |
| CTI | IEC 60112 | V | ≥600 | ≥600 |
| Mechanical Property | ||||
| Strength of peeling from glass | ASTM D 903 | N/cm | ≥65 | ≥65 |
| Strength of peeling from back-sheet | ASTM D 903 | N/cm | ≥65 | ≥65 |
| Tensile strength (cured), MD | ASTM D882 (MD) | MPa | ≥5.0 | ≥5.0 |
| Tensile strength (cured), TD | ASTM D882 (TD) | MPa | ≥5.0 | ≥5.0 |
| Elongation at break (cured), MD | ASTM D882 (MD) | % | ≥500 | ≥500 |
| Elongation at break (cured), TD | ASTM D882 (TD) | % | ≥500 | ≥500 |
| Shrinkage Rate | ||||
| Machine direction (MD) | ASTM D2732 | % | ≤3.0 | ≤3.0 |
| Transverse direction (TD) | ASTM D2732 | % | ≤1.5 | ≤1.5 |
| PID Resistance | ||||
| Power loss of PV modules | IEC 62804-2 | % | ≤5.0 | ≤5.0 |
| Aging Property (Durability) | ||||
| UV light resistance (120 kWh/m²) | ISO 15106-3, 85°C; 85% RH; 1000 hrs | ΔYI | <5.0 | <5.0 |
| Heat / humidity resistance (DH1000h) | ISO 15106-3, 85°C; 85% RH; 1000 hrs | ΔYI | <5.0 | <5.0 |
| Yellow index | ISO 15106-3, 85°C; 85% RH; 1000 hrs | ΔYI | <5.0 | <5.0 |
| Peel strength with glass | ISO 15106-3, 85°C; 85% RH; 1000 hrs | N/cm | ≥40 | ≥40 |
When preparing gel content samples, the sample preparation structure should be stacked according to the BOM of the actual PV modules.
PID test condition: 85°C, 85% RH, 1500 Vdc, and 288 h.
ASTM — American Society for Testing and Materials · IEC — International Electrotechnical Commission · IS — Indian Standard.
Application
Recommended Lamination for Glass-Glass Modules
After opening the original package, it is recommended to use the product within 8 hours.
| Lamination parameter | Double-chamber laminator | |
|---|---|---|
| First step | Second step | |
| Hot plate actual temp. | 110~135°C | 140~155°C |
| Vacuum time | 360s~390s | 0~30s |
| Press time | 1 min~8 min | 8 min~14 min |
The above process conditions are representative examples and should be adjusted to the performance of the laminator, the components of the PV modules, etc. The optimised process condition can be chosen by measuring the gel content (>75%) of the encapsulant film in the PV modules.
The gel content in the marked area is more than 80%. The values shown are for reference only; the actual lamination conditions should be decided on the real gel content required for the module application.
First step: 110~135°C — Vacuum 6 min 30 s — Press 30 s (~70 kPa) — Press 30 s (~50 kPa) — Holding (X-7) min (~30 kPa).
Second step: 140~155°C — Vacuum 10 s — Press 10 s (~70 kPa) — Press 10 s (~50 kPa) — Holding X min (~30 kPa).
Handling & Storage
Keeping the Film in Specification
Precautions
- Film should not be exposed to the atmosphere for a long time. Significant exposure will cause a decrease in functionality.
- Store in a cool, dry, and well-ventilated place. Keep away from heat and sunlight, and keep away from active oxidizing materials.
- Avoid making contact with bare hands, water, oil, organic solvents and other chemicals.
Storage Conditions
- 1.The product shall be stored indoors at temperature between 0°C and 30°C, and humidity below 60% RH.
- 2.Avoid direct sunshine, and keep away from heat and dust.
- 3.Shelf life of SS-EPE UVT-F & SS-EPE UVC-B products is 5 months from the production date.
- 4.Use up within 6 hours after opening.
The specifications and key characteristics covered in this datasheet may vary slightly with continuous innovation and improvement in comparison to actual products. Saatvik reserves the right to adjust the above information accordingly at any time without prior notice. *T&C apply.
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