| HS Code | 570780 |
| Solar Heat Rejection | High rejection of near-infrared solar radiation |
| Visible Light Transmittance | Wide range of transmittance options from clear to deeply tinted |
| Uv Protection | Blocking of over 99% of harmful ultraviolet rays |
| Infrared Absorbing Function | Contains nano-sized IR-absorbing particles |
| Neutral Color Appearance | Maintains natural color balance without excessive blue or bronze tint |
| Glare Reduction | Reduces visual glare from sunlight |
| Adhesion To Glass | Excellent bonding strength when used as an interlayer for laminated glass |
| Optical Clarity | Low haze and high transparency for unobstructed visibility |
| Thickness Range | Available in controlled thicknesses typically around 15 to 40 microns |
| Durability | Resistant to yellowing, weathering, and long-term solar exposure |
| Tensile Strength | High mechanical strength for handling and lamination processes |
| Elongation At Break | Sufficient flexibility to support glass bending and shaping |
As an accredited S-LEC Solar Control Film factory, we enforce strict quality protocols—every batch undergoes rigorous testing to ensure consistent efficacy and safety standards.
| Packing | S-LEC Solar Control Film is packaged in moisture-protected, sealed rolls, each measuring 100 meters in length and 1.5 meters wide. |
| Container Loading (20′ FCL) | 20′ FCL loading: S-LEC Solar Control Film rolls packed in cartons, secured on pallets, weight-optimized for safe transport. |
| Shipping | S-LEC Solar Control Film ships as rolls on sturdy cores, sealed in moisture-barrier packaging with desiccant to prevent hydrolysis. Handle with care to avoid edge damage, and keep upright or flat in a cool, dry area away from UV and heat. Transport per standard chemical safety guidelines. |
| Storage | Store S-LEC Solar Control Film in a cool, dry, well-ventilated area away from direct sunlight, UV rays, and heat sources. Keep it in its original sealed packaging to prevent moisture absorption and contamination. Recommended storage temperature is 5–35°C. Avoid sharp objects, heavy pressure, or bending that could damage the film. Use within the stated shelf life for optimal performance. |
| Shelf Life | Store in a cool, dry place; use within six months of manufacture. Protect from moisture, heat, and direct sunlight. |
In high-volume automotive glazing cells, S-LEC Solar Control Film is unwound from roll stock and laminated as a single-ply or paired-ply PVB interlayer. The interlayer ratio for a standard windscreen is 2.1 mm float glass / 0.76 mm S-LEC Solar Control Film / 2.1 mm float glass, yielding a nominal post-autoclave thickness of 4.96 mm; for mass-sensitive side laminates the stack is frequently reduced to 2.0 mm / 0.76 mm / 2.0 mm. Regulatory coverage is provided by UN ECE R43, ANSI Z26.1, and GB 9656-2021; the critical driver vision zone requires luminous transmittance of at least 70% under ECE R43, which constrains the solar control PVB to be paired with clear glass and a non-infrared-absorbing clear PVB when the windshield carries an additional tinted or coated outer lite. Matched-pair sag bending is run in continuous furnaces at 580–620°C, after which the interlayer is acclimatized for 24–48 h in a cleanroom held at 18–22°C and 20–40% RH to stabilize tack and moisture before layup. De-airing uses a two-stage nip-roll line at 5–12 m/min; autoclave conditions are held at 125–135°C, 11–13 bar, for 60–120 min. Finished part categories include automotive windscreens, laminated side lites, and rear-quarter glass units. The dominant batch failure mode is residual PVB moisture above 0.50 wt% by Karl Fischer titration, which produces edge bubbles after autoclaving and haze after humid storage; rolls exposed to ambient RH above 60% without re-drying are rejected because the increased tack causes nip-roll adhesion and glass-to-glass misregistration.
Large fixed panoramic roof modules use a three-ply interlayer stack because the heat-strengthened outer lite and ceramic frit edge create a thermal gradient during autoclave, making a single 0.76 mm ply insufficient for post-breakage edge retention after roof impact. The ply stack is normally 2.1 mm heat-strengthened outer / 2.28 mm S-LEC Solar Control Film / 1.6–2.1 mm heat-strengthened inner, with the interlayer built from three 0.76 mm plies to reach 2.28 mm. Type-approval is handled under UN ECE R43 for roof glazing and under ANSI Z26.1 for North American roof modules; optical distortion limits are enforced on the assembled laminate after autoclave according to the vehicle manufacturer’s derived grid test. Downstream processing begins with roller-hearth heat strengthening of the outer lite at 680–710°C, followed by controlled air quenching to a surface compression range of 24–52 MPa; the inner lite is printed with a ceramic frit and fired during the same heat-strengthening cycle. Vacuum-bag de-airing is held at -0.08 to -0.09 MPa for 20–40 min, then the laminate enters a horizontal autoclave at 132–138°C and 12–14 bar for 90–150 min. Finished component categories include fixed roof glass modules, sunroof cassettes, and panoramic roof replacement laminates. Roller-wave distortion above 0.25 mm on the outer lite cannot be corrected by interlayer flow during autoclave, so incoming glass is inspected before layup; this is a process constraint, not a downstream trimming correction.
Point-fixed facade lites assembled with multi-ply S-LEC Solar Control Film are governed by post-breakage retention tests rather than by film appearance alone. The primary standards are EN ISO 12543-2:2021, EN 12600 classification 1B1, and ASTM C1172; facade-specific load resistance is checked against ASTM E1300-23 or the relevant national annex. For a point-supported lite of 1.2 m × 2.5 m, the build is 6 mm heat-strengthened glass / 2.28 mm S-LEC / 6 mm heat-strengthened glass; when the long dimension exceeds 2.8 m, the outer lite is increased to 8 mm while the interlayer remains at 2.28 mm. Glass panels are cut and edge-seamed with 0.5 mm arris, then heat strengthened to surface compression 24–52 MPa. Lamination begins with a two-stage nip pre-press at 55–70°C and 95–115°C, line speed 2.5–4.0 m/min, followed by autoclave at 132–138°C, 12–14 bar, 120–150 min. When the outer lite carries a solar-control low-E coating, edge deletion of 12–20 mm is performed before layup to restore PVB adhesion at the perimeter. Point-bearing holes are water-jet or CNC diamond drilled after lamination; hole-edge chipping is held below 0.5 mm. Finished product groups include point-supported facade panels, glass elevator enclosure lites, frameless entrance screens, and all-glass corner increments. Reducing the interlayer to 1.52 mm in point-fixed panels shifts post-breakage retention outside the inclined creep test acceptance window; published data for site-specific point diameters is limited.
Where snow-load deflection and thermal stress act simultaneously, roof glazing procurement documents require CPSC 16 CFR 1201 Category II and EN 12600 Class 1B1 validation on the same laminate build. Load resistance is evaluated by ASTM E1300-23 or the project-specific Eurocode, while lamination quality is governed by EN ISO 12543-2:2021. The standard layup for an 1.8 m span is 6 mm heat-strengthened outer / 2.28 mm S-LEC Solar Control Film / 6 mm heat-strengthened inner; above 2.5 m the outer lite increases to 8 mm, with the 2.28 mm interlayer retained. The interlayer addition rate therefore remains constant at 2.28 mm while glass thickness scales with load, rather than increasing PVB thickness without load verification. Heat strengthening uses a roller hearth at 680–710°C with air quench to edge compression 24–52 MPa; glass is washed with demineralized water at conductivity below 20 μS/cm before lamination. Vacuum-bag de-airing is held at -0.08 to -0.09 MPa for 30–50 min, autoclave at 132°C, 12.5 bar, 120 min. Finished product categories include sloped skylight units, atrium roof glass, canopy screens, and overhead pass-way glazing. An annealed inner lite cannot be used where solar absorption raises center glass temperature above 45°C; edge stress beyond 18 MPa may initiate spontaneous fracture in clamped glazing channels.
Rail glazing programs qualify S-LEC Solar Control Film against mechanical impact and fire-load requirements simultaneously, which rules out thinner interlayers in cab positions. EN 15152-2 governs impact and retention for railway windscreens and windows; fire performance is assessed under EN 45545-2:2020; cab glazing follows UIC 651 optical and strength clauses. The standard side-window build is 4 mm chemically strengthened aluminosilicate outer / 1.52 mm S-LEC / 4 mm heat-strengthened inner. Cab windscreens are upgraded to 5 mm / 2.28 mm / 5 mm for impact and post-breakage retention. Aluminosilicate outer plies are CNC-cut, edge-seamed at 0.5 mm arris, and chemically strengthened in molten potassium nitrate at 420–460°C for 4–8 h depending on glass composition. Lamination is performed in cleanrooms at 20–30% RH, with PVB moisture conditioned to 0.40–0.50 wt% by Karl Fischer titration; vacuum-bag de-airing is set at -0.08 to -0.09 MPa; autoclave at 132°C, 12–13 bar, 120–180 min. Finished product categories include metro side windows, low-floor tram windscreens, high-speed rail cab glazing, and interior partition screens. Edge creep beyond 2 mm after 500 cycles between -40°C and +80°C is a common rejection criterion; residual interlayer moisture above 0.50 wt% accelerates delamination at aluminum frame interfaces and therefore limits supplier lot acceptance.
Marine wheelhouse glazing is selected by ply stack after the design pressure calculation of ISO 11336-1:2023, not by terrestrial facade norms alone; classification society certification by DNV or Lloyd’s Register confirms the type-approval status. A large-yacht wheelhouse windshield commonly uses 6 mm thermally toughened or chemically strengthened glass / 2.28 mm S-LEC Solar Control Film / 6 mm thermally toughened or chemically strengthened glass; side portlight safety panes use 4 mm / 1.52 mm / 4 mm. The outer and inner lites are bent to a cylindrical or compound radius and then strengthened; after washing and PVB conditioning at 18–22°C, 20–30% RH, the sandwich is vacuum-bag de-aired at -0.08 MPa and autoclaved at 130–135°C, 12 bar, 120 min. Bonding into aluminum or composite deckhouse frames uses polyurethane sealant with primer and 12 mm minimum edge engagement. Finished product categories include wheelhouse windshields, bridge-wing panes, deckhouse side glazing, and portlight safety laminates. Published data for this specific configuration is limited; the actual design pressure, pane size, and impact class must be checked against the vessel classification society and the supplier’s type-approval certificate before specifying the final ply stack.
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S-LEC Solar Control Film is an extruded polyvinyl butyral (PVB) interlayer manufactured by Sekisui Chemical for laminated glass applications in which selective attenuation of near-infrared solar energy is required without a sputtered metallic coating, body-tinted glass substrate, or post-applied retrofit film. The interlayer is supplied as roll stock with nominal thicknesses of 0.38 mm, 0.76 mm, 1.14 mm, and 1.52 mm. A 0.76 mm monolayer is the most common automotive windshield configuration, while 1.52 mm multi-ply laminates are specified for architectural overhead glazing, balustrades, and security glazing where post-breakage retention and residual load-bearing capacity are regulated. The product is not a self-adhesive surface-mounted film; it is an interlayer requiring lamination between glass plies in a controlled clean-room layup and autoclave consolidation.
The solar-control function is achieved by volumetric dispersion of an inorganic infrared absorber in the plasticized PVB matrix. The material is designed to reduce solar direct transmittance while retaining visible transmittance suitable for driver-vision zones. Photometric performance is assessed on the finished laminate rather than on the interlayer sheet alone, using ISO 9050 for visible transmittance, solar direct transmittance, and UV transmittance, and ISO 13837 for automotive solar transmittance. Grade codes are manufacturer-assigned and vary according to target visible transmittance, solar rejection class, and optional acoustic damping function. Published data for this specific configuration is limited outside the producer’s technical bulletins, so qualification testing on the selected glass build is required.
Incoming quality control of the interlayer is conducted on sheet stock prior to layup. The following matrix lists representative values for a solar-control PVB category; producer lot data should be obtained for the specific grade and thickness.
| Property | Test method | Representative value |
|---|---|---|
| Specific gravity | ISO 1183 | 1.07 |
| Tensile stress at break | ISO 527-3, crosshead speed 50 mm/min | >20 MPa |
| Elongation at break | ISO 527-3, crosshead speed 50 mm/min | >200 % |
| Moisture content | ISO 15512, Karl Fischer titration | <0.45 wt% |
| Haze | ASTM D1003 | <0.5 % |
| UV transmittance | ISO 9050, 300–380 nm | <1 % |
The tensile values in the table are film-based and thickness-independent for comparative purposes, but the adhesion response of S-LEC Solar Control Film to glass is governed by the hydroxyl content of the PVB resin, the plasticizer ratio, and the adhesion-control additive. Batch-to-batch variation in adhesion is controlled at the compounding plant by rheometric measurement of the melt and by laminate pummel testing on reference glass. At the lamination line, incoming sheet should be checked for moisture content and surface contamination. Silicone cutting-fluid residues, release sprays, and fingerprints can produce localized adhesion loss or haze after autoclave.
The interlayer consists of PVB resin plasticized with a long-chain ester plasticizer, with an inorganic infrared absorber dispersed during compounding. The PVB resin is formed by acetalization of polyvinyl alcohol with butyraldehyde; residual hydroxyl side chains are maintained at a controlled concentration to provide adhesion to glass through hydrogen bonding with silanol groups on the float-glass surface. The infrared absorber is selected to have an extinction maximum in the near-infrared region, generally between 780 nm and 2500 nm, while minimizing absorption in the visible 380–780 nm band. The exact absorber chemistry is proprietary; public technical literature identifies inorganic absorbers such as tin-doped indium oxide, antimony-tin oxide, and tungsten bronze systems, but the specific dispersion used in S-LEC Solar Control Film is not disclosed in supplier datasheets.
The solar-control additive does not fundamentally alter the standard PVB lamination sequence, but the higher near-infrared absorption of the sheet adds a marginal heat load during autoclave ramping. A qualified process record for a 0.76 mm monolayer on 2.1 mm clear float glass includes the following ranges.
| Parameter | Setpoint / tolerance | Measurement reference |
|---|---|---|
| Cut blank conditioning | 18–25 °C, 20–30 % RH for 24–48 h | Clean-room hygrometric control |
| Sheet moisture content | <0.45 wt% | ISO 15512, Karl Fischer titration |
| Nip-roller pre-pressing surface temperature | 60–80 °C | Contact pyrometer at roll gap |
| Vacuum-bag de-airing differential pressure | 0.08–0.095 MPa for 20–45 min | Vacuum gauge at bag manifold |
| Autoclave plateau | 130–140 °C at 1.2–1.5 MPa | Vessel pressure/temperature recorder |
| Time at plateau | 30–60 min after core glass reaches setpoint | Thermocouple in dummy laminate |
| Cooling before venting | <50 °C laminate surface | IR pyrometer or embedded probe |
Moisture control is the dominant variable in defect-free lamination. PVB is hygroscopic; at relative humidity above 30 % RH, cut blanks can take up water quickly. A moisture content above 0.45 wt% by Karl Fischer titration commonly creates interfacial vapour pressure during autoclave heating, producing microvoids and bubble clusters near the glass–interlayer interface. Conditioning at 20–30 % RH for 24–48 h is standard for cut blanks. Roll stock requires longer equilibration because the inner wraps are not in direct contact with the conditioned room atmosphere. Laminators with very short layup time after removal from storage may use sealed conditioning carts to stabilise moisture content.
In twin-screw compounding, the infrared absorber is dispersed into the plasticized PVB melt at the same high-shear mixing intensity used for adhesion-control additives. The compounding step typically uses a corotating twin-screw extruder with an L/D ratio near 40:1, followed by melt filtration to remove agglomerates that would otherwise create optical defects in the solar-control interlayer. The filtered melt is extruded through a flat die and embossed with controlled surface roughness; this roughness is an air-escape channel during roll de-airing and collapses during autoclave. Processing a solar-control grade without adequate filter media can produce visible IR-absorber agglomerates that appear as point haze defects after lamination. For this reason, melt filtration of the compounded sheet is a critical production-control step, not a cosmetic afterthought.
On the lamination line, the most common failure modes associated with solar-control PVB are not related to the IR absorber itself but to residual moisture, inadequate de-airing, or mismatched glass cooling. If the autoclave is vented above 50 °C, edge bubbles may form because the hot PVB is still compliant and the glass ply is not yet in full thermal equilibrium. Similarly, a rapid pressure drop during cooling can nucleate microvoids at the interface. The producer’s processing recommendations therefore specify slow cooling under pressure before venting, and thermocouple measurement inside a dummy laminate rather than reliance on vessel air temperature alone. Edge bubbles can also originate from glass-cleaning agents containing amide additives; such residues are not completely removed by demineralised-water rinse and can reduce interfacial adhesion. The laminate line should implement daily pummel adhesion tests on reference glass after autoclave. A drop in pummel value from 7 to 3 on the same glass lot and interlayer lot often indicates contamination rather than a change in interlayer adhesion chemistry.
S-LEC Solar Control Film operates by absorption rather than reflection. The absorbed near-infrared energy is conducted into the glass and re-radiated, producing a different surface temperature profile than a reflective low-emissivity coating with the same solar factor. The practical consequence is that the glass expands thermally in the solar-loaded area, and if that expansion is constrained by cold edges or irregular shading, tensile stress may exceed the allowable value. Thermal stress evaluation under DIN 18008-2 or ASTM E2431 is required for architectural glazing where partial shading is likely, particularly when the outer ply is heat-strengthened or when the pane is partially covered by building mass, printing, or adjacent structures. The allowable stress is defined in the relevant design standard; for thermally strengthened glass, design stress values are commonly in the range of 18–25 MPa, although national code and surface condition affect the final limit.
The absence of an electrically conductive silver layer eliminates electromagnetic-signal attenuation concerns and the requirement for edge deletion around telematics, toll transponders, radar sensors, or RF-based windshield systems. This property is relevant where radio-frequency transparency must be retained across the full glass surface. However, the interlayer does not provide a significant reduction in thermal infrared emissivity; a separate low-E coating in an insulated glass unit is required for cold-climate thermal insulation. In cooling-dominated buildings, the solar-control interlayer reduces solar heat gain, but the absorbed energy raises the glass surface temperature, which may affect occupant comfort near the glazing and must be accounted for in HVAC load calculations.
In architectural applications, the interlayer is commonly combined with a low-E coating in an insulated glass unit. The interlayer attenuates near-infrared solar energy, while the coating controls thermal infrared emissivity. This division of spectral duties yields a moderate solar factor in the 0.35–0.50 range with visible transmittance of 60–70 % depending on the cavity and coating stack. S-LEC Solar Control Film is not a substitute for a low-E coating where winter thermal insulation is the dominant energy load; its primary value is reduction of solar heat gain in cooling-dominated buildings and in automotive glazing with high solar exposure.
For automotive windshield applications, the laminated glazing must satisfy the optical, mechanical, and environmental requirements of ECE R43 or FMVSS 205, including visible transmittance in the driver vision zone, resistance to fragmentation, and adhesion after moisture, heat, and UV exposure. S-LEC Solar Control Film is formulated to reduce solar direct transmittance without reducing visible transmittance below the regulatory minimum. However, the interlayer modifies high-temperature creep compliance; therefore, headform impact, neck penetration, and roof-crush performance must be validated on the full glazing build rather than inferred from monolayer film data. The windshield laminate is typically constructed with the solar-control interlayer bonded to two plies of 2.1 mm or 1.8 mm glass, with the final thickness driven by the vehicle platform and acoustic requirements.
Where acoustic damping is specified, a trilayer solar-control acoustic grade can be used. The construction consists of a soft core layer between two stiffer skin layers, with the core tuned to increase sound transmission loss in the 1000–4000 Hz range relevant to wind noise and traffic sound. Measurement follows ISO 10140-2 for laboratory transmission loss or ISO 16940 for laminated glass. The combination of acoustic and solar-control functions in one interlayer eliminates the need for an additional acoustic film layer, but the final sound insulation is dependent on the total glass thickness and interlayer stack. Grade-specific loss factors should be obtained from the producer, because published data for every glass build is not available.
Automotive roof laminates with high solar load can reach surface temperatures above 70 °C under standing sun; the interlayer must maintain adhesion and mechanical stability at these temperatures. PVB-based interlayers are generally rated for continuous service below 80 °C, but short-term excursions require verification on the full laminate. The solar-control PVB also affects optical deviation; the windshield must meet the secondary-image and optical-deviation limits specified in the vehicle manufacturer’s drawing or in ECE R43. Interlayer thickness variation, surface roughness, and local flow during autoclave can create optical defects if the processing window is not maintained.
Against body-tinted glass, S-LEC Solar Control Film achieves near-infrared attenuation with less visible colour shift because the absorber is formulated to be neutral in the visible band. Body-tinted glass, by contrast, absorbs across a broader wavelength range and typically transmits a green, grey, or bronze tint. The interlayer approach also permits the same clear glass inventory to be used for multiple glazing configurations; solar control is selected by the choice of interlayer, not by the float-glass melt. Against sputtered low-E coatings, the interlayer provides no substantial thermal infrared emissivity reduction as a stand-alone layer, but it avoids angular colour shift, conductive-layer edge deletion, and RF attenuation associated with some silver-based stacks. Against post-applied solar window films, the interlayer places the solar-control function inside the laminate, protected from abrasion, cleaning chemicals, and edge peeling. The trade-off is that the interlayer cannot be retrofitted; the glazing must be fabricated on a lamination line with controlled clean-room, de-airing, and autoclave capability.
Compared with ionomer-based structural interlayers, S-LEC Solar Control Film is a PVB system and therefore follows the moisture sensitivity and lower high-temperature stiffness typical of PVB. It is not the preferred interlayer for open-edged structurally glazed units with continuous high humidity because moisture ingress at the edge can cause delamination. Edge protection with silicone or polysulfide sealants is required, but compatibility with the specific PVB formulation must be tested because some sealants can create plasticizer migration or adhesion loss at the edge.
