| HS Code | 527281 |
| Product Name | Sveck White II EVA Film SV-15297W |
| Model | SV-15297W |
| Manufacturer | Sveck |
| Application | PV encapsulation materials |
| Color | White |
| Thickness | 0.45 mm |
| Density | 0.95 g/cm³ |
| Melt Flow Rate | 20±5 g/10 min |
| Melting Point | 70±5 °C |
| Light Reflectance | ≥90% |
| Adhesion To Glass | ≥80 N/cm |
| Adhesion To Backsheet | ≥60 N/cm |
| Tensile Strength | ≥15 MPa |
| Elongation At Break | ≥500% |
| Volume Resistivity | ≥1×10^15 Ω·cm |
| Dielectric Constant | 2.8±0.2 |
| Breakdown Voltage | ≥20 kV/mm |
| Shrinkage | ≤3% |
| Water Absorption | ≤0.1% |
| Gel Content | ≥80% |
| Uv Cut Off Wavelength | ≤360 nm |
| Curing Temperature | 150 °C |
| Curing Time | 10 min |
| Storage Temperature | 5-30 °C |
| Shelf Life | 6 months |
As an accredited Sveck White II EVA Film SV-15297W (for PV encapsulation materials ) factory, we enforce strict quality protocols—every batch undergoes rigorous testing to ensure consistent efficacy and safety standards.
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In monofacial utility-scale module lamination, SV-15297W is positioned as the rear encapsulant between the cell string and the backsheet. The film is not a diluted additive at the module production stage; it is a continuous pigmented EVA sheet whose rear-side dose is determined by thickness and cut area. At a nominal thickness of 0.45 mm and an EVA density of 0.96 g/cm³, the applied mass is 432 g/m²; at 0.50 mm, the corresponding mass rises to 480 g/m². In a conventional glass-backsheet stack, the front transparent EVA contributes a second 0.45 mm sheet, so total encapsulant mass over a 2.5 m² module area is approximately 1,110–1,140 g. The rear white sheet occupies 100% of the rear encapsulation plane and is cut with an edge overhang of 5–10 mm per side to allow for reflow and post-lamination edge bleed of 0.5–1.5 mm. Compliance for finished modules is evaluated under IEC 61215-2:2021 design qualification sequences including MQT 11 thermal cycling from −40 °C to +85 °C for 200 cycles and MQT 13 damp heat at 85 °C and 85% RH for 1000 h, with power degradation held below 5%. Safety qualification falls to IEC 61730-2:2023, and raw-film chemical restrictions are aligned with REACH SVHC and RoHS 2011/65/EU. Production-scale lamination is carried out on three-chamber vacuum laminators with platen temperature uniformity of ±2 °C. The chamber is evacuated to ≤30 mbar for 4–6 min before the diaphragm press engages at 0.06–0.09 MPa for 8–10 min; total cycle time is 14–18 min, and post-lamination gel content above 75% is verified by ASTM D2765-18. White EVA with a rear sheet thickness of 0.50 mm is selected when cell gap spacing is 2.0–2.5 mm to maximize internal reflectance. The white pigmented rear sheet is not compatible with bifacial or transparent-backsheet constructions because rear-side irradiance is attenuated; bifacial modules require transparent rear encapsulation. Terminal finished products include 182 mm and 210 mm half-cell glass-backsheet modules rated from 540 W to 620 W for utility-scale arrays.
Residential modules using black polyethylene terephthalate or polyamide backsheets cannot rely on rear-sheet reflection; the reflective function shifts to the white EVA rear encapsulant. In this configuration the white sheet is placed directly behind the cell plane, reflecting photons that pass through cell gaps back toward the front glass. The formulation ratio at the module level is identical to utility formats: a 0.45 mm rear SV-15297W sheet contributes 432 g/m², or 50–52 wt% of total encapsulant mass when paired with a 0.45 mm front transparent EVA. Cut dimensions follow cell-string layout with a 3 mm allowance on all sides; operators monitor edge bleed to 0.8–1.5 mm to avoid white pigment migrating onto visible front surfaces. If roll storage RH exceeds 60%, condensation must be removed and the roll conditioned at 25 °C for 24 h before layup to prevent lamination bubbles. Module-level compliance is tested under IEC 61215-2:2021 MQT 10 UV preconditioning, MQT 11 thermal cycling, and MQT 13 damp heat; safety-related fire performance is assessed under IEC 61730-2:2023. Production lamination runs at a platen setpoint of 145 °C, with 5 min vacuum and 8–10 min press, followed by gel content verification above 75% per ASTM D2765-18. Published data for cell-to-module gain specific to SV-15297W in all-black residential modules is limited; the optical contribution depends on cell pitch, ribbon width, and front glass transmittance rather than on EVA reflectance alone. Terminal products include 410–445 W residential all-black modules using 120 half-cells in 182 mm wafer format.
| Process parameter | Glass-backsheet utility configuration | Double-glass BIPV configuration | Test or measurement method |
|---|---|---|---|
| Rear white EVA thickness | 0.45 mm | 0.50 mm | Mechanical scanning per ISO 4593:2019 |
| Rear encapsulant mass | 432 g/m² | 480 g/m² | Calculated from density 0.96 g/cm³ |
| Platen setpoint | 145 °C | 148 °C | Thermocouple array |
| Vacuum dwell | 4–6 min | 5–7 min | Chamber pressure gauge |
| Diaphragm press | 0.06–0.09 MPa | 0.07–0.10 MPa | Regulator manometer |
| Press dwell | 8–10 min | 10–12 min | Laminator timer |
| Post-lamination gel content | ≥75% | ≥80% | ASTM D2765-18 |
Curtain-wall and rainscreen building-integrated photovoltaic panels use SV-15297W not only as an encapsulant but also as the rear opacifying layer when the back glass is required to conceal submodule wiring and mounting rails. In a typical BIPV spandrel stack, the rear white EVA is used at 0.50 mm, corresponding to 480 g/m²; it is paired with a 0.45 mm transparent front EVA and 4 mm or 6 mm heat-strengthened front glass, with rear glass from 3.2 mm to 6 mm. The white sheet covers 100% of the opaque visual plane, and its pigment loading prevents rear-side visibility without requiring an additional opacifying film. Compliance for BIPV modules is assessed under EN 50583-1 and EN 50583-2 for building integration, with impact resistance by EN 12600 and fire classification under EN 13501-1; electrical qualification remains aligned with IEC 61215-1:2021 and IEC 61730-1:2023. Lamination for double-glass BIPV panels uses a three-chamber laminator with platen temperature at 148 °C and vacuum dwell of 5–7 min because the rear glass reduces effective heat transfer to the inner encapsulant. Press dwell is extended to 10–12 min at 0.07–0.10 MPa to bring gel content above 80%, and edge seal butyl is applied before layup to reduce moisture ingress at the exposed facade edge. Production observations on double-glass lines show that temperature lag across the rear glass can create a 3–5 °C difference between front and rear EVA if platen contact is uneven; carrier plate flatness is therefore checked to ≤0.5 mm deflection per meter. Terminal products include spandrel panels, balcony balustrade cladding, fixed shading louvers, and non-load-bearing facade elements.
Agrivoltaic canopy modules use large-area single-glass formats and long rows with repeated thermal cycling; shortened lamination dwell is sometimes requested to raise throughput, but SV-15297W crosslinking is sensitive to both time and temperature. The rear sheet is applied at 0.45 mm (432 g/m²) or 0.50 mm (480 g/m²), with the wider format cutting allowance set to 5–10 mm per edge. Qualification includes IEC 61215-2:2021 MQT 11 thermal cycling, MQT 12 humidity-freeze from 85 °C / 85% RH to −40 °C, and MQT 13 damp heat. Lamination is performed at 145 °C with vacuum 4–6 min and press 8–10 min; if total cycle time is compressed below 14 min, gel content can fall below 75% under standard cure profiles, and rework increases because adhesion to the backsheet is insufficient after damp heat exposure. The laminator control system must maintain platen temperature uniformity below ±2 °C; a drop of 3 °C at the edge zone shifts local gel content by several percentage points, producing visible white bands or edge delamination. Published data for SV-15297W-specific gel content versus dwell time is limited, but the operational boundary is fixed by peroxide-initiated crosslinking kinetics, not by film thickness alone. Terminal products include 400–500 W canopy modules using 182 mm or 210 mm half-cells, typically with galvanized steel support structures and 5–10° tilt angles for agricultural shading.
Off-grid solar water pumping stations operate in rural tropical and subtropical climates where humidity and temperature swing accelerate backsheet delamination. In these laminates the white EVA rear sheet is cut to 100% of the active area at 0.45 mm, providing 432 g/m² rear encapsulant mass; the front transparent EVA is 0.45 mm, giving a near-symmetric mass split. The production layup places the white film between the cell string and a PET-based backsheet; edge bleed is controlled to 0.5–1.5 mm. Compliance is verified under IEC 61215-2:2021 MQT 13 damp heat at 85 °C and 85% RH for 1000 h, followed by MQT 11 thermal cycling, with peel adhesion tested by ASTM D1876-08 or equivalent T-peel method. The pass/fail criterion is the absence of interfacial delamination extending more than 3 mm from the module edge after damp heat. Lamination runs at 145 °C for 14–18 min, with vacuum 4–6 min and press 8–10 min. Post-lamination conditioning at 25 °C and 50% RH for 24 h is maintained before peel testing because adhesion develops as residual peroxide decomposes. Terminal finished products include 100–300 W off-grid solar water pump modules paired with AC or DC pump controllers.
For flexible photovoltaic laminates used on recreational vehicle roofs and marine canopy tops, SV-15297W serves as the rear encapsulant where white opacity and surface protection are required without a rigid backsheet. The rear sheet is applied at 0.30 mm (288 g/m²) on low-wattage modules or 0.45 mm (432 g/m²) on larger panels, with cut alignments following rectangular cell banks and no glass edge constraints. Compliance for these flexible modules is evaluated under IEC 61215-2:2021 mechanical load and damp heat sequences as applicable to non-glass front sheets, with adhesion tested after 85 °C / 85% RH exposure; front sheet optical properties are verified by ASTM D1003-21 haze and transmittance. Lamination is performed on roll-to-roll or tray-based laminators at 135–145 °C, with dwell times from 12–18 min depending on film thickness and front sheet thermal resistance. The process requires lower platen pressure of 0.04–0.06 MPa to avoid cell cracking in thin laminates, and gel content is verified by ASTM D2765-18. Terminal products include 50–200 W flexible modules for RV roofs, marine bimini canopies, and portable solar charging panels.
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Sveck White II EVA Film SV-15297W (for PV encapsulation materials) is an ethylene-vinyl acetate encapsulant grade specified for rear-side encapsulation in crystalline-silicon photovoltaic modules. The film is supplied as roll goods and is positioned between the cell string and the backsheet or second glass sheet. Because SV-15297W is controlled for use on production lamination lines, lot-specific values for thickness, width, roll length, melt flow index, gel content after cure, peel strength, and volume resistivity are documented in the supplier’s certificate of analysis rather than reproduced as fixed figures. The following technical description identifies the applicable test methods, industrial processing limits, and process risks that determine whether the film performs within a given module stack. Lamination is typically executed on single- or multi-step vacuum laminators with platen temperatures in the range of 140 °C–155 °C, but the exact cure schedule must be confirmed for the module dimensions, laminator model, and backsheet configuration. Storage before lamination should maintain the film at 5 °C–30 °C and below 60 % relative humidity to limit moisture uptake, bubble formation, and acetic acid generation during the thermal cycle.
In a rear-side white encapsulant, light passing through cell gaps, ribbon shadows, and non-active perimeter zones is reflected back toward the active cell surface. Spectral reflectance in the 400 nm–700 nm band is measured with a spectrophotometer equipped with an integrating sphere in accordance with ASTM E903-20. The resulting reflectance curve is used to estimate photon recycling in cell-gap regions, although module-level electrical gain must be confirmed separately because optical behavior changes after lamination. Haze and luminous transmittance of transparent front-side reference films are characterized by ASTM D1003-21; this method is not the primary specification for a rear-side white film. The white appearance of SV-15297W is associated with a mineral pigment dispersion, typically titanium dioxide. That inorganic phase increases visible reflectance but also modifies melt rheology, dielectric behavior, and cohesive failure mode. Yellowness index after damp-heat exposure is monitored according to ASTM E313-20 on laminated glass/EVA/glass coupons because raw-film optical values do not capture post-lamination interface oxidation or pigment redistribution.
Reflectance is thickness-dependent and formulation-dependent. A thicker white layer increases hiding power and photon recycling but also adds mass and may require a longer vacuum dwell for bubble escape. For production audits, reflectance at 550 nm is frequently tracked because it correlates with visible light recycling and can be measured rapidly on a bench-top spectrophotometer with an integrating sphere. Comparisons between SV-15297W and transparent EVA should not be based on luminous transmittance; the white film is not intended for front-side placement ahead of the cell. Module-level electrical response due to rear-side reflection is quantified through current–voltage characterization under IEC 60904-1, with the module under test compared against a reference build using a transparent rear encapsulant. Published data for this specific configuration is limited, so the electrical gain attributable to rear-side reflection is best determined through a module maker’s laminated-cell experiment rather than a film-level optical value alone.
Raw-film handling before lamination is governed by moisture control. EVA absorbs water from ambient air; absorbed moisture above approximately 0.1 % by weight may cause bubble formation during heating and contribute to hydrolysis that releases acetic acid. If storage conditions exceed 60 % RH, pre-drying at 40 °C–45 °C for 12 h–24 h in a desiccant dryer is commonly used before layup. Melt flow index of the raw film is measured according to ISO 1133-1:2022. A lower melt flow index indicates higher melt viscosity and can slow bubble escape in single-chamber laminators with limited vacuum dwell time. Tensile strength and elongation at break before and after cure are tested per ASTM D638-22, with results tracked as part of incoming lot acceptance. The thickness profile across the web is verified with a non-contact capacitance gauge; variation above ±0.03 mm across a production roll can produce laminate thickness differences and localized pressure marks during lamination. The film should not be stored in direct contact with materials that exude amine-based slip agents or silicone oils, because surface contamination can interfere with peroxide cure and produce localized adhesion loss.
Crosslinking of the EVA matrix is initiated by organic peroxide decomposition during the lamination press stage. The peroxide system is selected so that the film melts and wets the glass and cell surfaces before the cure rate accelerates. Gel content after lamination is used as a production proxy for crosslink density and is determined by solvent extraction in boiling xylene or by methods derived from ASTM D2765-16. For EVA encapsulants of this class, the industrial acceptance window after cure is generally 70 %–90 % gel content. Values below 60 % indicate under-cure and may produce low peel strength, poor cohesion, and reduced adhesion after damp-heat exposure. Values above 95 % may increase brittleness and reduce adhesive failure energy, particularly at module edges. On multi-step vacuum laminators, a typical cycle includes a vacuum dwell stage at 120 °C–130 °C followed by a press stage at 145 °C–155 °C for 10 min–15 min. Platen temperature uniformity is mapped with a thermocouple array and should be maintained within ±2 °C across the module area. Larger deviation produces gel-content gradients, edge adhesion defects, and post-lamination delamination at the perimeter. Batch-to-batch variability in peroxide content or pigment dispersion can shift gel-content rise time, so incoming lots are sampled with a cure-rheometer trace to detect abnormal induction time or cure-rate behavior before changing lamination parameters.
Adhesion and electrical isolation after damp-heat aging are more sensitive to under-cure than visual appearance. Peel strength to glass is measured after lamination with a tensile tester using a 90° or 180° peel fixture per ASTM D6862-11(2021) or an internal method aligned with IEC 61215-2:2021. Under-cured EVA typically shows peel-strength loss after damp-heat at 85 °C/85 % RH for 1000 h according to MQT 13 of IEC 61215-2:2021, with failure concentrated at the glass–encapsulant interface. Volume resistivity and surface resistivity are measured per ASTM D257-14(2021) on laminated specimens. Industrial acceptance values for reliable wet-leakage performance are typically above 1 × 10¹⁴ Ω·cm for volume resistivity, but the exact SV-15297W value is lot-specific and confirmed in the certificate of analysis. Wet leakage current and insulation resistance are verified at module level per IEC 61215-2:2021 MQT 15 and MQT 16. Because polar vinyl acetate segments and residual peroxide decomposition products influence charge transport, cure state and adhesion are monitored jointly rather than as independent acceptance criteria. Potential-induced degradation susceptibility is assessed at module level per IEC TS 62804-1; EVA-based encapsulants can generate acetic acid under negative potential, and low gel content may increase ionic mobility. The film is therefore qualified in combination with the intended glass, cell surface, and backsheet, not as an isolated film.
Differences between SV-15297W and transparent EVA are primarily optical. Transparent EVA is specified for the front side where broadband transmission is critical; the white rear film is placed behind the cell string to reflect stray light. Black EVA is used in aesthetic module constructions but absorbs visible light and can raise local equilibrium operating temperature under rear illumination. Compared with polyolefin elastomer (POE) encapsulant, EVA has a different water vapor transmission pathway and can generate acetic acid under damp-heat stress. POE is often specified for PID-sensitive modules, while EVA remains used in standard modules with appropriate PID-resistant cell surfaces and glass. The substitution of SV-15297W for transparent rear EVA may require lamination parameter changes because white-pigmented EVA has higher melt viscosity than transparent EVA of the same vinyl acetate content, which can slow bubble escape and require a longer vacuum dwell. Process engineers typically execute a design-of-experiments with 0.45 mm, 0.50 mm, and 0.60 mm film thicknesses, checking gel content, peel strength, and optical appearance at 5 min, 10 min, and 15 min cure intervals to define the edge of the processing window. The final process is confirmed by module-level wet leakage, damp-heat, and adhesion testing under IEC 61215-2:2021.
In single-chamber laminators with large heated platens, edge-cooling can reduce local temperature at the module perimeter. If the edge-cure temperature falls below the peroxide activation threshold for a significant portion of the cycle, the edge seal remains under-cured and can fail in peel testing even when the module center passes. Thermocouple mapping of a production laminator is therefore as important as film-level gel-content testing. Field observations across EVA lamination lines indicate that platen temperature nonuniformity above ±2 °C correlates with measurable gel-content variation. Module manufacturers repeat thermocouple mapping after heating-element replacement or platen resurfacing. For SV-15297W, the same cure-state acceptance rules apply as for other EVA grades: the edge coupon is extracted from the module perimeter and tested for gel content and peel strength separately from the center coupon. A common defect pattern is low edge peel strength after 85 °C/85 % RH damp-heat testing, even when initial crosslinking appears adequate. Post-lamination inspection on white rear encapsulants should include electroluminescence testing per IEC TS 60904-13, because high rear reflectance can mask certain visual defects and cell cracking that would otherwise be identified by optical inspection alone.
| Property or test | Test method/standard | Typical industrial acceptance window | SV-15297W lot status |
|---|---|---|---|
| Gel content after lamination | Solvent extraction; methods derived from ASTM D2765-16 | 70 %–90 % | Lot-specific; certificate of analysis |
| Peel strength to glass | ASTM D6862-11(2021) / IEC 61215-2:2021 | Process-dependent; module qualification limit applies | Lot-specific; laminate coupon test |
| Volume resistivity | ASTM D257-14(2021) | Typically above 1 × 10¹⁴ Ω·cm | Lot-specific |
| Yellowness index after damp-heat | ASTM E313-20 | Process-defined upper limit | Coupon-level |
| Wet leakage current | IEC 61215-2:2021 MQT 15 | Module limit | Module-level |
| Insulation resistance | IEC 61215-2:2021 MQT 16 | Module limit | Module-level |
