Products
Products
Products
| HS Code | 572973 |
| Tensile Strength | 220 MPa (MD/TD) |
| Elongation At Break | 120-200% |
| Young S Modulus | 3.5-5.5 GPa |
| Density | 1.39 g/cm³ |
| Melting Point | 255-265 °C |
| Glass Transition Temperature | 70-80 °C |
| Dielectric Strength | 150-300 kV/mm |
| Surface Tension | 38-42 dyn/cm |
| Transparency | Visible light transmittance >85% |
| Haze | <3% |
| Water Absorption | <0.8% (24h immersion) |
| Thermal Shrinkage | 1.5-3% at 150°C for 30 minutes |
| Coefficient Of Friction | 0.4-0.6 (kinetic) |
As an accredited BOPET Film factory, we enforce strict quality protocols—every batch undergoes rigorous testing to ensure consistent efficacy and safety standards.
| Packing | BOPET Film is packed in roll form with protective anti-static wrapping, securely boxed on pallets; quantity: 500 kg per roll. |
| Container Loading (20′ FCL) | Biaxially oriented polyester film rolls loaded tightly into 20-foot FCL, secured with dunnage to prevent movement and damage. |
| Shipping | BOPET film ships as rolled master/jumbo rolls on sturdy cores, wrapped in moisture-barrier packaging with edge protection to prevent scratches and telescoping. It’s non-hazardous, but requires dry, clean transport and careful handling. Avoid rough loading, impact, or high temperatures to preserve film flatness and optical clarity. |
| Storage | Store BOPET film in a clean, dry, cool environment, ideally at 10–30°C with relative humidity below 60%. Keep rolls upright on pallets, protected from direct sunlight, dust, moisture, and sharp objects. Use original packaging or opaque, padded wrapping to prevent scratches, deformation, and static damage. |
| Shelf Life | Typical shelf life is 2 years when stored cool, dry, and protected from UV light in original packaging. |
A 12 µm biaxially oriented polyethylene terephthalate film is adhesive-laminated to a 70 µm LLDPE sealant web on a 1,200 mm wide duplex laminator running at 250 m/min. The polyurethane adhesive is a two-pack solventless system applied at 2.0–2.5 g/m² with an isocyanate-to-polyol mix ratio of 100:45 parts by weight. Prior to lamination, the film is reverse-printed by gravure after corona treatment to 48–52 dyn/cm; web tension is maintained at 80–120 N/m because registration drift at tension above 140 N/m causes misalignment of resealable opening strips on pouches. The clear 12 µm film has oxygen transmission of approximately 120 cm³/m²·day·atm at 23 °C, 0% RH under ASTM D3985, while vacuum-metallized 12 µm BOPET reduces OTR below 1.0 cm³/m²·day·atm. Tensile properties are 210–250 MPa MD and 220–260 MPa TD per ASTM D882, with elongation at break of 100–140% MD. Compliance is governed by FDA 21 CFR 177.1630 and EU Regulation 10/2011, with overall migration below 10 mg/dm² in olive oil simulant for 10 days at 40 °C. Terminal laminates are supplied for coffee pouches, snack packaging, frozen poultry lidding, and retortable pouches where seal-jaw temperatures of 140–180 °C are used and the BOPET layer provides dimensional stability against creep under hot-seal pressure.
On a five-roll offset gravure coater, a solventless platinum-catalyzed silicone release system is applied to a co-extruded BOPET facestock at 1.0–1.5 g/m² dry coat weight and cured in a forced-air oven at 150 °C for 4–6 s. The facestock uses a silicone-anchoring copolyester skin on one surface and a non-treated or chemically primed reverse surface; the core layer is formulated for tensile strength of 200–250 MPa MD per ASTM D882 and haze below 8% per ASTM D1003. Release force is verified by FINAT FTM 3 at 12–45 cN/2.5 cm, covering easy-release and tight-release grades; residual adhesive strength is tested by FINAT FTM 11 and must remain above 85%. Silicone anchorage is checked by Sutherland rub testing for 500 cycles at 1.8 kg, with no visible rub-off. The film is supplied in 23–50 µm thickness with a tolerance of ±2%. At 300 m/min line speed on a 2.0 m web, relative humidity above 60% leads to electrostatic sticking and sheet misfeeding; active ionizing bars are installed before the rewind. Finished liners are converted into labelstock release bases, double-sided tape liners, medical wound-care liners, and protective-film carriers. Silicone transfer to the adhesive must remain below the detection limit by Fourier-transform infrared spectroscopy or X-ray photoelectron spectroscopy surface analysis because even trace transfer reduces subsequent tack below the specified 1.0 N/25 mm peel-force threshold.
The backsheet core uses 250 µm hydrolysis-resistant BOPET produced from resin with carboxyl end-group concentration below 20 meq/kg, compounded with 5–8 wt% rutile titanium dioxide for UV opacity and 0.3–0.5 wt% hindered phenolic antioxidant. The film is corona-treated to 52–56 dyn/cm and extrusion-laminated between a UV-stabilized fluoropolymer outer layer and a polyolefin tie layer at a die temperature of 290–320 °C, nip pressure 4–6 MPa, and line speed 60 m/min. Hydrolysis kinetics are acid-catalyzed; the low carboxyl end-group content and antioxidant package retard autocatalytic chain scission under damp heat. Damp-heat aging at 85 °C and 85% RH for 2,000 h under IEC 61215-1:2021 conditions shows that hydrolysis-resistant grades retain above 50% elongation at break, while standard packaging-grade BOPET can drop below 10% elongation after 1,500 h; published data for specific backsheet configurations is limited because tie-layer and fluoropolymer properties dominate the failure envelope. Shrinkage at 150 °C for 30 min is held below 0.8% MD per ASTM D1204 to prevent lamination curl. Electrical safety is evaluated under IEC 61730-1:2023 and IEC 62788-2:2022; partial discharge and insulation resistance are assessed on the complete backsheet rather than on the PET core alone. The BOPET layer is not used as a UV-facing outer surface without a fluoropolymer or stabilized polyolefin cover because unprotected film embrittles after 1,500 h of UV-A exposure. The final construction is used in glass-backsheet modules where the PET layer supplies dielectric spacing and moisture resistance between the cell string and the rear encapsulant.
For capacitor film production, a sequential biaxial orientation line is operated with casting drum temperature at 25 °C, machine-direction draw ratio 3.2–3.4, transverse-direction draw ratio 3.6–3.8, and heat-setting at 225–235 °C with 5–8% transverse relaxation. Thickness gauges of 2 µm, 3 µm, 4 µm, and 6 µm are wound with a thickness tolerance of ±0.3 µm over 1,000 m roll lengths, monitored by a traversing beta gauge. The film contains low particulate filler loading, typically below 100 ppm, to reduce protrusion defects that cause localized electric-field intensification. Surface roughness is controlled between 0.02 µm and 0.05 µm Ra on the metallization face to allow uniform zinc-aluminum alloy deposition at 2–6 Ω/sq sheet resistance in a 1.5 m wide vacuum metallizer. Dielectric constant is 3.2–3.4 at 1 kHz per ASTM D150-18, dissipation factor is 0.002–0.005 at 1 kHz, and volume resistivity exceeds 10^17 Ω·cm per ASTM D257. Breakdown strength per IEC 60674-3-2 increases as gauge decreases, rising from approximately 250 V/µm at 6 µm to above 450 V/µm at 2 µm, but the absolute voltage rating per layer falls with thinner film. Thermal shrinkage at 200 °C for 10 min is limited to 2.0% MD and 1.0% TD per ASTM D1204. The main production failure mode is gauge banding caused by chatter in the transverse stretching chain, which produces local hot spots during metallization and partial discharge. The wound metallized film is slit on a Kampf-type slitter to ±0.2 mm width tolerance; edge burrs below 0.1 mm are required. End products include motor-run capacitors, surface-mount device capacitors, snubber capacitors, and high-frequency DC-link capacitors where the BOPET dielectric provides self-healing behavior after micro-arcing.
| Parameter | Test method | 2 µm | 6 µm |
|---|---|---|---|
| Thickness tolerance | Beta gauge scanning | ±0.3 µm | ±0.5 µm |
| Dissipation factor at 1 kHz | ASTM D150-18 | 0.004 | 0.003 |
| Breakdown strength at 25 °C | IEC 60674-3-2 | >450 V/µm | >250 V/µm |
| Thermal shrinkage 200 °C/10 min MD | ASTM D1204 | <2.5% | <1.8% |
| Surface roughness Ra metallization face | Profilometer | 0.02–0.04 µm | 0.03–0.05 µm |
Thermal transfer ribbon base film is converted from 4.5–5.5 µm BOPET with a silicone release backcoat at 0.1–0.3 g/m² and a front-side wax-resin or resin ink layer at 2.0–3.0 g/m². The backcoat is applied by reverse-gravure coater and dried at 90–120 °C; the ink layer is slot-die coated and dried in a 15 m oven at 80–110 °C. The film must withstand printhead temperatures of 300 °C for 0.1 s without tearing, so MD thermal shrinkage at 150 °C for 30 min is limited to 0.8% per ASTM D1204 and breaking strength is maintained at 220–250 MPa per ASTM D882. A critical slitting defect is edge burr, which causes printhead dot loss and wax build-up; tungsten carbide blades with pressure set at 0.25–0.35 MPa are used to maintain edge quality below 0.05 mm burr height. Web tension is maintained at 60–90 N/m; above 120 N/m, orientation slip produces wrinkles that are not recoverable in the finished roll. The terminal products are barcode and shipping-label ribbons, ticketing ribbons, and RFID label printer ribbons.
Once a 50 µm BOPET outer layer is adhesive-laminated to a 40 µm LLDPE sealant web, the inner surface is gravure-coated with a peelable heat-seal lacquer at 5–8 g/m² dry coat weight. The lacquer is formulated with low-molecular-weight polybutene and EVA terpolymer to widen the seal plateau; seal initiation temperature is 135–145 °C and the peelable plateau extends to 170 °C. Form-fill-seal machines set jaw temperature at 160 °C, dwell 1.5 s, and pressure 0.4 MPa. Peel force is measured by ASTM F88-21 at 1.5–2.5 N/15 mm, because lower values risk seal failure during ethylene oxide sterilization and higher values cause fiber tear or container deformation. Sterile barrier performance is validated under ISO 11607-1:2019, with bubble leak testing at 0.08 MPa internal pressure and dye penetration per ASTM F1929-15. Cytotoxicity is assessed by ISO 10993-5:2009; chemical extractables are tested under 21 CFR 177.1630 migration protocols. The BOPET side is kept resistant to seal transfer at 180 °C jaw temperatures; a heat-resistant backside coating of 0.5–1.0 g/m² is applied when required. End products include chevron pouches, Tyvek-lid base stock for syringes, and form-fill-seal lidding for alcohol wipes and surgical devices.
For motor slot liner production, 75–125 µm BOPET is first slit on a rotary shear slitter to width tolerance ±0.1 mm and then laminated to Nomex-type meta-aramid paper with a 5 g/m² flame-retardant acrylic adhesive. The laminate is die-cut with 0.1 mm clearance between punch and die to avoid edge cracking at bends. The BOPET layer provides dielectric strength under ASTM D149 and is rated UL 94 VTM-0 at 125 µm thickness. In liquid-filled motor tests, the slot liner must withstand 2,000 V AC for 1 min without breakdown after conditioning at 85 °C and 85% RH for 48 h; standard packaging-grade BOPET may fail this test because of hydrolysis, whereas hydrolysis-resistant electrical grades are selected. The lamination process runs at 30 m/min with nip pressure 2.5 MPa; excessive pressure crushes the aramid paper and reduces mechanical cushioning. Terminal products are inserted as ground-wall and phase insulation in fractional-horsepower motors, transformer layer insulation, and voice-coil former insulation.
Hard-coated BOPET in 125 µm or 175 µm thickness serves as the printed top-layer substrate in membrane touch switches and graphic overlays. The coating is a UV-cured acrylic or siloxane hardcoat applied at 2–5 µm wet film thickness and cured under a 120 W/cm mercury lamp at 20 m/min. Pencil hardness per ASTM D3363 is 2H–3H; Taber abrasion per ASTM D1044 using CS-10 wheels and 500 g load shows haze increase below 10% after 500 cycles. Crosshatch adhesion per ASTM D3359 remains 5B after 24 h water immersion at 23 °C. Screen-printing uses UV-curable solvent-resistant inks at a mesh count of 305–380 threads/in; the ink stack is overprinted with a dielectric spacer and conductive silver circuit below in a four-wire resistive design. Die-cut buttons require 0.25 mm radius corners to avoid stress concentration and cracking at actuation. The operational boundary is flex life: the BOPET overlay is not recommended for continuous dynamic flexing below 2 mm bend radius, where polycarbonate or polyimide alternatives may be required. End products include medical instrument keypads, industrial control faceplates, and handheld terminal lens windows.
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Biaxially oriented polyethylene terephthalate film, designated BOPET in converting specifications and supplier grade nomenclature, is produced by flat-die extrusion of dried polyethylene terephthalate resin, electrostatic pinning to a chilled casting drum, and sequential or simultaneous biaxial orientation on a tenter frame. The resin is melted in a single-screw or twin-screw extruder with L/D ratio 30:1 to 40:1 and melt temperature 285–300 °C; undried or partially dried resin hydrolyzes in this zone and reduces die-pressure stability. The amorphous cast sheet is reheated to 95–110 °C for machine-direction stretching at a draw ratio of 2.8:1 to 3.5:1, then stretched transversely at 110–140 °C with a ratio of 3.0:1 to 4.0:1 before heat-setting at 210–230 °C. Commercial thicknesses span 12 µm through 350 µm; ultra-thin capacitor grades at 4.5 µm and 6 µm are available but require high-stiffness slitter geometry to prevent fold-over at speeds above 400 m/min. Density is specified by ISO 1183-1:2019 as 1.40 g/cm³ for unfilled film. The model nomenclature encodes thickness, surface treatment, and end-use class: a 23 µm corona-treated lamination grade may be designated T23C, while a 250 µm white voided grade may be designated W250. Resin intrinsic viscosity before extrusion is typically 0.62–0.68 dL/g measured in 60/40 phenol/1,1,2,2-tetrachloroethane at 30 °C; retention after drying and extrusion is monitored because a drop below 0.50 dL/g corresponds to a measurable loss in flex-crack resistance. Incoming resin is dried at 170 °C for 4–5 h to <50 ppm moisture; residual water above 50 ppm drives hydrolysis in the extruder, producing die-lip deposits and optical gel counts above 10 particles/100 cm² on inspection systems operating at 405 nm.
Unfilled BOPET formulations contain small loadings of antiblock and slip agents. Antiblock is typically a synthetic silica with median particle size 3–6 µm at addition levels of 0.05–0.30 wt%. Slip control is achieved with migrating amide or polysiloxane technologies, but these additives lower surface energy and interfere with print and lamination anchorage when overdosed; converter specifications therefore limit slip loading to levels that maintain dynamic coefficient of friction below 0.35 without reducing surface wetting tension below 38 dyn/cm. White voided grades contain 5–15 wt% titanium dioxide and an incompatible dispersed phase that cavitates during machine-direction orientation. Cavitation reduces density to 1.05–1.25 g/cm³ and increases opacity to 90–95%; void formation is sensitive to transverse-direction draw ratio deviations above 0.2%, which can create visible die lines under polarized light inspection.
Thermal shrinkage is measured according to ASTM D1204-14 by exposing a 100 mm × 100 mm specimen to 150 °C for 30 min in a forced-air oven. Standard BOPET grades show machine-direction shrink of 1.0–2.5% and transverse-direction shrink of 0.5–2.0%; heat-stabilized grades reduce values to 0.5–1.0% in both axes. The residual shrinkage arises from incomplete relaxation of oriented amorphous tie molecules during heat-setting. A processing window of ±5 °C around the heat-set zone dominates batch-to-batch variation on tenter lines: below 205 °C the film retains enough orientation to shrink beyond 2.5% at 150 °C, while above 235 °C the film surface roughens and haze increases above 3.0%.
On sequential biaxial orientation lines, bowing distortion appears as a transverse-direction shrinkage gradient across the web. Converters measure edge-to-center delta using an offline IR shrinkage simulator with ±0.1% dimensional resolution. For lamination grades shipped to gravure printers, an edge-to-center machine-direction shrink difference above 0.4% causes registry drift on presses running at 250 m/min. Heat-stabilized film is produced with additional annealing rolls at 215–225 °C and reduced transverse-direction relaxation. Published data for high-temperature annealing above 240 °C is limited because commercial tenter frames typically reach only 235 °C before film blocking occurs. Crystallinity after heat-setting, measured by differential scanning calorimetry at 10 °C/min, is 45–55%. This crystalline fraction limits thermoforming; BOPET cannot be deep drawn below a radius-to-thickness ratio of 3:1 without cracking.
Moisture vapour transmission rate, oxygen transmission rate, and optical clarity are specified in supplier data sheets with ASTM and ISO methods. A 12 µm clear BOPET film typically exhibits oxygen permeability of 80–150 cm³/(m²·day·atm) at 23 °C, 0% RH under ASTM D3985-17 and water vapour transmission of 20–35 g/(m²·day) at 38 °C, 90% RH under ASTM F1249-20. These values are thickness-dependent; below 12 µm, the relationship deviates from simple inverse-thickness scaling because skin–core orientation differences and surface nucleated crystallinity alter the amorphous free volume distribution. Haze for clear film is <3.0% by ASTM D1003-21 using CIE Illuminant C, and total light transmission is 88–92%. The coefficient of friction is controlled with precipitated silica or organic slip additives to a dynamic value of 0.30–0.50 under ASTM D1894-13. For metallized barrier grades, aluminium is deposited onto the corona-treated surface at optical density 2.0–2.8, reducing oxygen permeability to 0.1–1.0 cm³/(m²·day·atm) and water vapour transmission to 0.3–1.5 g/(m²·day). The metallized barrier collapses if the base film surface roughness Ra exceeds <2.0 nm; therefore base film is filtered through an online optical profilometer with 0.1 nm vertical resolution. Where maximum moisture barrier is required, PVdC-coated BOPET at a dry coating weight of 2–3 g/m² reduces water vapour transmission to 4–12 g/(m²·day) and oxygen permeability to 2.0–10.0 cm³/(m²·day·atm). This configuration is used in pharmaceutical blister lidding for low-moisture products but does not replace aluminium foil where light barrier and oxygen transmission below 0.01 cm³/(m²·day·atm) are required.
BOPET is not the primary barrier layer in high-humidity retort pouches because ester linkages undergo hydrolytic chain scission above 105 °C under steam pressure. The failure mode is measured by tracking elongation at break after retort cycles of 30 min at 121 °C and 0.21 MPa. A standard 12 µm film can lose 30–60% of elongation after 60 min exposure, with the degradation rate increasing as intrinsic viscosity falls below 0.45 dL/g. This is why BOPET is positioned as the print web or outer reinforcement layer in retort structures, while biaxially oriented nylon or cast polypropylene is selected for the direct food-contact and moisture-driven barrier layer. Biaxially oriented nylon absorbs 3–5% moisture at 65% RH and loses oxygen barrier as humidity rises; BOPET absorbs 0.3–0.5% moisture and retains its oxygen barrier more stably, but its hydrolytic stability under saturated steam is inferior to polypropylene. Accelerated acid-free water immersion at 100 °C for 72 h is used by suppliers to predict chain scission. Published data for this specific configuration is limited across all commercial grades, and converters therefore run pilot lamination trials before committing to retort specifications.
Corona treatment raises the surface energy of BOPET from its intrinsic 42–44 dyn/cm to >52 dyn/cm immediately after treatment; ASTM D2578-17 wetting tension tests are typically specified at 38–42 dyn/cm after 30 days. For solventless polyurethane adhesives, the film should be treated to >48 dyn/cm and laminated within 48 h because treatment decay follows a logarithmic curve with a half-life of 7–14 days on aluminium foil-facing surfaces. Chemical primers based on polyethyleneimine or polyurethane are applied at 0.05–0.15 g/m² dry coat weight. These primers interact with the ester surface through hydrogen bonding and improve adhesion of water-based inks. On gravure printing lines, untreated or insufficiently oxidized BOPET fails tape adhesion tests after ink laydown; film with surface oxygen content below 15 atomic % by X-ray photoelectron spectroscopy shows ink transfer values below 80%. A dyne level above 50 dyn/cm on a freshly treated roll can exist with poor printability if oxidation is non-uniform. Therefore converters monitor not only wetting tension but also water contact angle hysteresis, with a target below 10°.
Substitution of BOPET for BOPP is driven by the need for higher modulus, higher temperature resistance, or lower oxygen permeability, but the change introduces a density penalty and stiffness differences. BOPET has a machine-direction tensile modulus of 3,500–4,500 MPa under ASTM D882-18, compared with 1,500–2,100 MPa for biaxially oriented polypropylene. At 12 µm, BOPET provides oxygen permeability of 80–150 cm³/(m²·day·atm), while biaxially oriented polypropylene at 20 µm typically exceeds 1,500 cm³/(m²·day·atm). The heat-seal initiation temperature of BOPET is above 120 °C if amorphous copolyester sealable skins are absent; biaxially oriented polypropylene can be sealed at 110–130 °C with a random copolymer layer. Thus reverse-printed BOPET is usually adhesive-laminated to a sealant web.
| Property | BOPET 12 µm | BOPP 20 µm | BOPA 15 µm | Test method |
|---|---|---|---|---|
| Density | 1.40 g/cm³ | 0.91 g/cm³ | 1.14–1.16 g/cm³ | ISO 1183-1:2019 |
| Tensile strength, machine direction | 200–260 MPa | 120–180 MPa | 200–300 MPa | ASTM D882-18 |
| Elongation at break, machine direction | 100–180% | 150–250% | 80–150% | ASTM D882-18 |
| Oxygen permeability, 23 °C, 0% RH | 80–150 cm³/(m²·day·atm) | 1,500–2,500 cm³/(m²·day·atm) | 20–50 cm³/(m²·day·atm) | ASTM D3985-17 |
| Water vapour transmission, 38 °C, 90% RH | 20–35 g/(m²·day) | 4.0–7.0 g/(m²·day) | 100–200 g/(m²·day) | ASTM F1249-20 |
| Continuous service temperature | 150 °C | 120 °C | 120 °C | Supplier data |
| Dimensional stability, 150 °C, 30 min | 0.5–2.5% | Not rated at 150 °C | 1.0–3.0% | ASTM D1204-14 |
Substitution of BOPET for BOPA in snack packaging removes the moisture-dependent oxygen-barrier variability of nylon but changes the moisture absorption and stiffness profile. Biaxially oriented polyamide at 15 µm absorbs 3–5% moisture at 65% RH, while BOPET at 12 µm absorbs 0.3–0.5%. For high-temperature lamination, BOPET is preferred because its storage modulus at 150 °C remains above 1,000 MPa, whereas oriented nylon loses stiffness above its glass transition region and under absorbed moisture. These property trade-offs determine layer substitution only after the full pouch geometry and fill weight are fixed.
Capacitor-grade BOPET is specified with dielectric strength above 300 kV/mm at 23 °C under ASTM D149-20 and volume resistivity above 10^15 Ω·cm under ASTM D257-14. Thickness variations below ±1% across the web are required to prevent hot-spot failure in metallized film capacitors; such film is produced with online beta-gauge thickness scanning and automatic die-bolt adjustment. Release liner styles use a silicone coating applied at 1.0–1.5 g/m² to a primed BOPET base. The base film must exhibit low extractable oligomer levels below 0.5% by Soxhlet extraction with xylene for 6 h, because oligomer migration above 0.5% interferes with anchorage and creates haze in optical applications. Solar backsheet film is UV-stabilized with hindered amine light stabilizers and titanium dioxide loadings of 5–15 wt%, with weathering qualification under IEC 62788-2 and electrical breakdown methods under IEC 60674-2. Thermal transfer ribbon base film uses thickness 4.5–12 µm with heat resistance to 200 °C for 10 s without elongation above 1%. The backcoat provides release and anti-static function; surface resistivity of the backcoat is specified below 10^9 Ω/sq to avoid static charging on high-speed barcode printers.
| Grade class | Primary specification | Typical requirement | Reference method |
|---|---|---|---|
| Clear packaging film | Haze, coefficient of friction, oxygen permeability, water vapour transmission | Haze <3.0%, dynamic COF 0.30–0.50, OTR 80–150 cm³/(m²·day·atm) at 12 µm, WVTR 20–35 g/(m²·day) at 12 µm | ASTM D1003-21, ASTM D1894-13, ASTM D3985-17, ASTM F1249-20 |
| Metallized base | Surface roughness and wetting tension | Ra <2.0 nm, dyne ≥48 dyn/cm | Optical profilometer, ASTM D2578-17 |
| Heat-stabilized | Unrestrained shrink at 150 °C, 30 min | ≤1.0% both axes | ASTM D1204-14 |
| Electrical | Dielectric strength, thickness tolerance | ≥300 kV/mm, ±1% | ASTM D149-20, beta gauge |
| Release liner | Extractables, silicone anchorage | Extractables <0.5%, no rub-off after cure | Soxhlet xylene, T-peel |
| Solar backsheet | Weathering, electrical breakdown | Module-specific; no single numeric requirement applies | IEC 62788-2, IEC 60674-2 |
