| HS Code | 332187 |
| Thickness | 0.45 mm |
| Density | 0.95 g/cm³ |
| Melt Flow Index | 25 g/10 min |
| Light Transmittance | ≥91% |
| Uv Transmittance | ≥90% (280–380 nm) |
| Adhesion To Glass | ≥80 N/cm |
| Adhesion To Backsheet | ≥40 N/cm |
| Tensile Strength | ≥18 MPa |
| Elongation At Break | ≥500% |
| Volume Resistivity | ≥1×10^15 Ω·cm |
| Dielectric Breakdown Voltage | ≥30 kV/mm |
| Water Vapor Transmission Rate | ≤15 g/m²·24h |
| Gel Content | ≥80% |
| Thermal Shrinkage | ≤3% |
| Curing Time | 8–10 min at 145 °C |
As an accredited FIRST Super Fast-Cure EVA Film Su806 (UV transmittance) factory, we enforce strict quality protocols—every batch undergoes rigorous testing to ensure consistent efficacy and safety standards.
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Photovoltaic module production lines using 2.0 mm tempered front glass, a PERC or TOPCon cell matrix, and a single-layer backsheet operate with lamination cycle constraints governed by peroxide decomposition and gel content development in the encapsulant. The Su806 film is processed in a dual-chamber vacuum laminator with platen temperatures set from 142 °C to 150 °C. Fast-cure behavior reduces the time above 135 °C to approximately 6.5 min to 8.5 min, after which the gel content measured by ASTM D2765-16 Method B crosses the 70% threshold required for post-lamination adhesion retention. High UV transmittance across the 280 nm to 400 nm band, measured as solar-weighted direct transmittance under ASTM E903-20, changes the spectral dose reaching both the cell surface and the backsheet interface. In rear-emitter PERC modules, the UV-transparent encapsulant maintains photon flux into the passivation stack, but the backsheet must tolerate the transmitted fraction without embrittlement; therefore the acceptable lamination window is not defined solely by crosslink density. It is also bounded by the UV absorber package and by the residual peroxide concentration after cure. Production-scale failure modes observed on fast lines include incomplete gel at the module perimeter, corner delamination after damp heat exposure at 85 °C and 85% RH for 1000 h, and busbar-side bubble formation when vacuum pressure is released before edge temperature exceeds 138 °C. Line validation data typically compare peel adhesion after IEC 61215-1:2021 damp heat with initial gel content mapped at nine points across a 2.2 m × 1.1 m laminate; edge positions more than 9 °C below platen setpoint show lower gel content and constitute the critical inspection zone.
| Parameter | Method | Operational relevance |
|---|---|---|
| Total luminous transmittance and haze | ASTM D1003-21 | Visual quality and photon path through laminated glass modules |
| Spectral UV transmittance | ASTM E903-20 | UV dose to cell, backsheet, and decorative interlayers |
| Gel content after press cure | ASTM D2765-16 Method B | Crosslink density and adhesion stability |
| Melt flow rate before cure | ISO 1133-1:2022 | Edge flow and ribbon embedment uniformity |
| Damp heat resistance | IEC 61215-1:2021 | Encapsulant adhesion and optical retention under 85 °C/85% RH |
Bifacial module stacks replace the polymer backsheet with a second glass sheet, doubling thermal mass and slowing the heating ramp at the encapsulant layer adjacent to the rear glass. The same fast-cure formulation used in glass-backsheet construction cannot be transferred directly to glass-glass lamination without remapping platen setpoints and cycle times. Platen temperatures are typically raised by 3 °C to 6 °C relative to glass-backsheet lines, and the vacuum hold is extended until the rear-side encapsulant reaches the minimum crosslinking temperature before membrane pressure is applied. UV transmittance becomes a dual-sided variable: front-side UV photons pass through the front glass and front encapsulant, while rear-side diffuse UV from ground reflection enters through the rear glass and rear encapsulant. The combined UV dose accelerates chain scission in any low-stabilizer region, particularly at cell edges where local temperature lags and crosslink density is lowest. A high-UV-transmittance film may increase rear cell current under ASTM G173-23 spectral conditions, but published data for the specific Su806 configuration in bifacial stacks is limited; module makers therefore verify the rear-side spectral response on their own cell vendor stack. The critical production control is gel content symmetry between front and rear encapsulant layers. When rear gel content falls below 65% while front gel content exceeds 78%, the asymmetry produces interfacial stress during thermal cycling, and delamination initiates at the cell corner. The edge zone within 12 mm of the glass perimeter is the highest-risk area because moisture ingress and under-cure overlap. Laminator validation includes nine-point gel content mapping after IEC 61215-1:2021 thermal cycling, and UV preconditioning is used to detect early yellowing. Optical retention below 95% of initial transmittance after UV exposure indicates that the fast-cure peroxide system has left an active residue that accelerates chromophore formation.
In building-integrated photovoltaic facades and curtain-wall laminates, the encapsulant is simultaneously an optical interlayer, an adhesion layer, and a component of a safety-glazed assembly. The lamination cycle for Su806 in BIPV modules is constrained not only by cure completion but also by the bowing limits of heat-strengthened glass at press temperature. Fast-cure film allows platen dwell times short enough to limit glass sag; line data from vacuum press operations indicate that reducing time above 140 °C from 14 min to 7 min lowers edge warp in 4 mm to 6 mm glass units by more than 30%. High UV transmittance in facade applications is generally undesirable unless the spandrel unit is designed for UV-cured edge tapes or UV-sensitive photovoltaic cells; therefore the film is frequently paired with a UV-blocking coating or UV-opaque ceramic frit on the exterior glass. The interface between EVA and silicone facade sealant is a known failure site. Neutral-cure silicone sealants that release alcohol by-products during curing are used, but unreacted phthalate plasticizers from certain edge tapes soften the EVA and reduce peel strength after thermal cycling. For safety glass classification, the as-built laminate is evaluated under EN 12600 and the interlayer must maintain adhesion without cohesive failure. Since building codes vary, a qualification test under EN ISO 12543-2 is required for the specific glass build-up before supply; no generic EVA interlayer data is accepted. The production audit must include optical quality after lamination, measured by ASTM D1003-21, and UV transmittance mapping because the same roll may show variation across width from the cast film process.
Horticultural laminated glass uses an interlayer that must transmit enough UV-A and UV-B radiation for plant photomorphogenesis and pathogen suppression while blocking UV-C below 280 nm. The Su806 film is characterized by ASTM E903-20 in the 280 nm to 400 nm band, and the resulting transmittance curve is weighted against the solar spectral irradiance in ASTM G173-23 to compute the UV dose behind the laminate. Fast-cure behavior is relevant in the batch lamination of mid-sized greenhouse glass panels because the short press dwell reduces heat-induced distortion of the tempered substrate. A production concern in this segment is the uniformity of UV transmittance after accelerated weathering: EVA formulations with high initial UV transmittance may exhibit rapid loss in the 300 nm to 340 nm region if the UV absorber package is reduced. Published data for the specific Su806 configuration in horticultural laminated glazing is limited; therefore each batch is evaluated by measuring spectral transmittance before and after accelerated weathering according to ASTM G154-23. The adhesion requirement is less severe than in safety glazing, but bubble formation at the glass-film interface during diurnal temperature cycling is a common failure mode when the film is not pre-dried at RH above 60%. Panels installed at high solar altitude show edge yellowing first because the sealant edge zone retains more moisture and receives reflected UV from metallic framing.
Because flexible polymer front sheets distort above 132 °C, fast-cure EVA films are not automatically low-temperature curing materials. Su806 still requires a minimum platen-side temperature above 138 °C for reliable gel content, and this creates a narrow processing window when the front sheet is ETFE or a UV-stabilized PET composite. Flexible module lamination is performed in a membrane press with digital pressure control, typically maintaining pressure below 0.5 MPa during ramp to avoid cell microcracking and front sheet thinning. The fast-cure peroxide system reduces dwell at the upper temperature, but the front sheet must be pre-shrunk at 120 °C and the film must be pre-dried when storage RH exceeds 60%; moisture absorbed by EVA before lamination produces voids at the cell grid lines during vacuum release. UV transmittance in flexible modules has a direct effect on the backsheet or rear coating. Because the stack is thinner than glass modules, a higher fraction of the incident UV reaches the rear encapsulant interface, where adhesion loss and chalking can initiate. Manufacture-side adhesion testing after damp heat is based on peel force at the cell-encapsulant interface; adhesion loss greater than 30% of the as-laminated peel value after 1000 h at 85 °C and 85% RH is considered a process failure on many flexible module lines. The primary process conflict is between cure speed and edge heating uniformity: thin flexible stacks heat quickly in the center, but the edge region under the press frame lags by 5 °C to 8 °C. Laminator mapping with thermocouples embedded between front sheet and encapsulant is required before line acceptance.
Furniture-grade laminated glass and interior decorative panels place a different demand on the interlayer: optical clarity, bubble-free adhesion, and dimensional stability of embedded inserts. Fast-cure EVA film is used in double-chamber vacuum laminators with silicone membranes because short cycle times permit small-batch production of design panels without autoclave investment. If the embedded insert is a UV-sensitive textile, printed film, or polyurethane foam, the high UV transmittance of Su806 limits its suitability unless a UV-blocking outer layer or screen-printed frit is added. When transparent UV transmission is required to cure an adjacent adhesive or to maintain a crisp visual effect under UV lighting, the film is processed at the lower end of the cure window to avoid excessive flow into porous inserts. The processing failure in this segment is not under-cure but interlayer flow: at temperatures above 150 °C, melt flow rate measured by ISO 1133-1:2022 increases enough to cause edge squeeze-out and optical distortion around metallic mesh inserts. Production controls include differential temperature ramps, since the insert acts as a heat sink and can depress local temperature by 4 °C to 6 °C relative to the glass. For interior glass, scratch resistance and adhesion are evaluated by EN 12600 only when the panel is intended as safety glass; otherwise visual inspection under ASTM D1003-21 is used to quantify haze after lamination. High UV transmittance is not a universal advantage in this segment, and panels exposed to direct sunlight or high-output UV lamps can exhibit localized yellowing of the decorative insert before the EVA itself shows optical loss.
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Product designation FIRST Super Fast-Cure EVA Film Su806 (UV transmittance) identifies a fast-crosslinking ethylene-vinyl acetate encapsulant roll manufactured for photovoltaic module lamination. The grade is supplied as a cast film in typical thicknesses of 0.40 mm, 0.45 mm, 0.50 mm, and 0.60 mm, with roll width and length configurable to module layup. The film contains ethylene-vinyl acetate copolymer, an organic peroxide crosslinking initiator, a silane adhesion promoter, and a stabilization package formulated to retain a defined ultraviolet spectral window. The UV-transmittance designation distinguishes this product from UV-blocking EVA grades that incorporate higher-efficiency UV absorbers. Independent published data for this specific Su806 configuration is limited; the processing parameters and acceptance limits described below should be confirmed against the manufacturer’s current technical data sheet and product qualification report.
In photovoltaic module construction, the encapsulant is laminated between glass, cell strings, and a backsheet or a second glass sheet. The Su806 film is intended for high-throughput flat-plate lamination lines where dwell time at the cure plateau is a production bottleneck. The fast-cure designation indicates a shortened cure plateau relative to standard EVA grades, but the actual cycle-time reduction is equipment-specific and must be established by gel-content measurement and module-level adhesion testing on the production line.
The fast-cure property of Su806 derives from an accelerated organic peroxide decomposition profile. In standard EVA lamination, the cure plateau at platen temperatures of 145°C to 150°C typically requires 12 min to 18 min depending on module thermal mass. Fast-cure formulations reduce the required plateau by shifting the peroxide half-life and by increasing the efficiency of the crosslinking co-agent. The specific peroxide system is not disclosed by the supplier; however, organic peroxides with 1 h half-life temperatures in the range of 120°C to 140°C are commonly used in EVA encapsulant formulations. The film’s crosslinking density develops only after the peroxide decomposition temperature is reached, so the cure plateau must be adjusted for glass thickness, backsheet thermal conductivity, cell spacing, and laminator platen uniformity.
A representative lamination recipe for thin glass-backsheet modules uses vacuum evacuation to 30 Pa to 80 Pa for 180 s to 300 s, followed by membrane pressure of 0.08 MPa to 0.10 MPa and a cure plateau of 8 min to 12 min at platen set points of 145°C to 150°C. These values are starting points from supplier processing guidance and are not guaranteed acceptance criteria. For glass-glass modules or arrays with wide cell gaps, thermal lag may extend the time required to reach the film’s crosslinking temperature. Platen temperature uniformity should be verified with a calibrated multi-point contact thermocouple array and maintained within ±2 K to ±3 K. Wider deviations produce nonuniform crosslinking, edge adhesion loss, or void formation at module corners. The primary process conflict is the narrow margin between sufficient crosslinking and premature peroxide decomposition. If the film is heated above 160°C before air removal is complete, curing can begin while gas is still trapped, creating voids that cannot be removed by membrane pressure. If cure is incomplete, gel content falls below the module maker’s acceptance limit and the encapsulant may creep or delaminate at service temperatures approaching 85°C.
Gel content is measured by solvent extraction according to ASTM D2765 or an equivalent internal method, with a typical acceptance value of ≥80% for EVA encapsulants after lamination. The fast-cure formulation may also exhibit higher room-temperature storage sensitivity. Rolls should be stored in sealed packaging at ≤30°C and ≤60% RH. Opened rolls should be consumed within 12 h to 24 h to avoid moisture uptake and pre-crosslinking caused by residual peroxide migration. Incoming film can be monitored for melt flow index by ASTM D1238 or by a controlled cure test followed by gel content measurement. Batch-to-batch variation in peroxide dispersion and silane grafting efficiency can shift the cure curve, so incoming quality control should include thickness profile, moisture content by Karl Fischer titration, and gel content after a defined cure cycle.
On high-throughput flat-plate laminators, the Su806 grade is introduced to reduce lamination cycle time. Cycle-time reduction is obtained only if vacuum and pressure sequences are shortened proportionally. In a multi-chamber laminator with separate preheat, cure, and cooling chambers, the bottleneck often shifts from the cure plateau to the glass heating rate or backsheet heat transfer. A PVF-based backsheet with lower thermal conductivity may require a longer preheat than a PET-based backsheet. Modules with 2.8 mm or thinner glass and single-cell strings typically achieve the shortest cure cycles; modules with 3.2 mm or thicker glass may require dwell times at the upper end of the recommended range. The film’s melt flow behavior before crosslinking influences bubble removal. If the melt viscosity is too low because of insufficient crosslinking or excessive temperature, edge bleed may occur. If the melt viscosity is too high because of pre-crosslinking, void formation may occur.
The UV-transmittance designation indicates a spectral transmittance profile that allows a larger fraction of the solar ultraviolet band to pass through the encapsulant than is permitted by UV-blocking EVA grades. Total luminous transmittance after lamination is measured by ASTM D1003; typical EVA encapsulant values are 90% to 92%, but grade-specific values must be taken from the supplier’s current datasheet. Spectral transmittance in the 280 nm to 400 nm interval is measured with a UV-Vis spectrophotometer calibrated according to ISO 9050 or an equivalent method. UV-blocking EVA films typically incorporate UV absorbers that reduce transmittance below 360 nm to less than 10%; a UV-transmittance EVA retains a defined transmittance in the 300 nm to 380 nm region. This characteristic may be specified for module designs with UV-responsive cell surfaces or for specific backsheet combinations in which the backsheet itself provides front-side or rear-side UV protection. The trade-off is that UV radiation reaching the cell and backsheet can contribute to UV-induced degradation of polymer layers, cell passivation, or ribbon interfaces.
Yellowness index is measured by ASTM E313; initial values after lamination should be below 2.0. Haze is measured by ASTM D1003; for front-side encapsulants, low haze is preferred to minimize light scattering. Differences from standard EVA include not only cure speed but also the UV absorber package. Standard EVA and UV-blocking EVA may contain higher concentrations of benzophenone, hydroxyphenyl triazine, or other UV absorbers; the Su806 UV-transmittance grade uses a reduced or modified absorber package. This is a formulation difference rather than a physical thickness or dimensional difference. Short-circuit current gain attributable to increased UV transmittance is cell-dependent and must be evaluated with spectral response measurement according to IEC 60904-8 or the module maker’s internal method. Published data for this specific Su806 configuration is limited; a direct performance claim without module-level measurement is not supported.
Initial adhesion of the cured Su806 film to glass and backsheet is evaluated by peel testing in accordance with ASTM D1876 or the module maker’s internal equivalent. Typical EVA encapsulant peel adhesion to glass after lamination is reported in the range of 30 N/cm to 60 N/cm, but the specific Su806 value must be taken from the manufacturer’s datasheet. The fast-cure formulation must achieve adequate silane condensation at the glass surface within the shortened cure plateau; otherwise, initial peel adhesion may be acceptable but damp heat adhesion retention may be reduced. Damp heat exposure per IEC 61215-2:2021 at 85°C and 85% RH for 1000 h is the primary reliability test for encapsulant adhesion and backsheet durability. After damp heat, the module should show no delamination, no bubbles, and no significant power loss.
Adhesion retention is influenced by the silane coupling agent type. Methacryloxypropyltrimethoxysilane and similar silanes are common in EVA encapsulant formulations. Fast-cure grades may use a silane with higher hydrolysis rate to develop adhesion quickly; this can also increase moisture sensitivity before lamination. Incompatibilities include amine-based additives, certain alkaline glass cleaning residues, and some polyamide backsheet edge seal materials. Alkaline residues on the glass surface can reduce adhesion and accelerate damp heat failure. The film should not be combined with UV-blocking backsheets that contain amine-stabilized UV absorbers if the grade’s UV transmittance creates a mismatch. For glass-glass modules with high system voltage, EVA-based encapsulants may have insufficient volume resistivity for some manufacturers. Volume resistivity is measured by ASTM D257; typical EVA values are lower than POE values. The Su806 UV-transmittance grade is not a drop-in replacement for POE in bifacial glass-glass modules where rear-side UV exposure, permanent UV protection, and high volume resistivity are specified. It can replace standard EVA in glass-backsheet modules if the backsheet UV resistance and cell UV stability are confirmed.
Qualification of modules using this film should include the test methods in the following compliance matrix. The values are representative for EVA encapsulant films and are not a substitute for Su806-specific acceptance limits.
| Property or test | Standard designation | Typical acceptance range |
|---|---|---|
| Gel content after lamination | ASTM D2765 | ≥80% |
| Total luminous transmittance | ASTM D1003 | 90% to 92% |
| Yellowness index | ASTM E313 | ≤2.0 initial |
| Peel adhesion to glass | ASTM D1876 | 30 N/cm to 60 N/cm |
| Damp heat exposure | IEC 61215-2:2021 MQT 12 | 1000 h, 85°C, 85% RH |
| Thermal cycling | IEC 61215-2:2021 MQT 11 | 200 cycles, −40°C to +85°C |
| UV preconditioning | IEC 61215-2:2021 MQT 10 | 15 kWh/m² to 60 kWh/m² |
| Volume resistivity | ASTM D257 | Typical EVA ≥1×10¹⁴ Ω·cm |
Batch release testing for the Su806 film should include thickness profile, gel content after controlled cure, total transmittance, yellowness index, and peel adhesion. Incoming quality control may also include moisture content by Karl Fischer titration because EVA films can absorb moisture from ambient air. If the film is stored at >60% RH, pre-drying at 40°C to 50°C for 2 h to 4 h is recommended before lamination. Failure to pre-dry can generate bubbles at cell edges. The film should be slit to the required width with clean blades to avoid edge defects that can propagate during lamination. Published data for the Su806 fast-cure UV-transmittance grade in alternative encapsulant structures such as transparent backsheets or thin-glass modules is limited; each module design therefore requires a separate qualification program under the relevant IEC 61215-2:2021 test sequence.
