Trosifol Clear

When Trosifol Clear is specified for laminated safety glass, the incoming film state controls downstream autoclave behaviour. The PVB roll is conditioned at 18 °C to 25 °C and 25% to 35% RH; a moisture content outside 0.30% to 0.50% will shift adhesion, reduce edge de-airing, and increase the probability of blow-in or edge cloud. The sheet is supplied in nominal thicknesses of 0.38 mm, 0.76 mm, 1.14 mm, and 1.52 mm, with roll widths up to 3210 mm depending on packaging configuration. At 23 °C and 0.40% moisture, the film exhibits a density near 1.07 g/cm³, tensile strength above 20 MPa, and elongation at break above 250%. The glass transition temperature lies between 15 °C and 20 °C, so the interlayer responds as a viscoelastic solid: low-rate shear deformation produces creep, while impact-rate deformation produces higher stiffness and energy absorption. These properties make lamination throughput dependent on film storage, glass surface condition, and autoclave thermal uniformity rather than on melt extrusion parameters.

Adhesion development is a hydrogen-bonding process between hydroxyl groups on the PVB and silanol groups on soda-lime-silica glass; float-glass tin-side orientation must therefore be identified before assembly. Pummel adhesion values for architectural laminates are generally maintained between 4 and 8, while automotive windshields are controlled between 3 and 7. Values below these ranges correlate with large glass spalling and high-speed impact failure; values above them reduce energy dissipation by limiting interlayer delamination and can produce brittle impact response. Because the pummel result depends on residual moisture, adsorbed surface contamination, and local autoclave humidity, a single lamination recipe cannot be transferred between plants without first qualifying the glass washing line and clean-room dew point. The film is also hygroscopic after the protective pouch is opened; open rolls should be consumed within a controlled interval, and partially used rolls must be resealed with desiccant packs.

Typical validation runs on industrial lines use the following process windows, with the understanding that local autoclave load density and glass emissivity will shift the time-to-core-temperature.

De-airing Temperature Defines the Cold-Bending Window for Facade Panels

Curtain wall, overhead, and balustrade laminates with Trosifol Clear are assembled in a clean room where relative humidity is held below 28% to prevent interlayer moisture uptake after conditioning. The cut interlayer is placed with an edge overhang of 3 mm to 8 mm; for CNC-profiled glass, the edge bite of the interlayer is reduced to less than 2 mm to minimise moisture wicking after installation. Vacuum bag de-airing is run to a residual pressure below 50 mbar, followed by heating to 60 °C to 110 °C before autoclave transfer. Autoclave bonding for facade panels operates at 12 bar to 14 bar and 135 °C to 140 °C, with dwell times from 90 min to 180 min depending on glass thickness, load density, and panel aspect ratio. Cooling under pressure to below 40 °C is required before unloading to avoid optical distortion and edge shrinkage. Terminal components include point-fixed facades, cantilever balustrades, overhead canopies, and structural glass fins where the interlayer must retain broken glass after impact. Compliance is generally assessed under EN ISO 12543-2, EN 12600, ANSI Z97.1, 16 CFR 1201, and ASTM C1172 depending on the project jurisdiction.

Cold bending imposes sustained shear on the PVB layer at the corner zones of curved panels. Because the interlayer has finite creep compliance, the edge bond and the gas-pocket-free interface must be qualified at the maximum design temperature, not at room temperature. A cold-bent facade panel with a 1.52 mm Clear interlayer can pass initial optical inspection but later develop edge delamination at service temperatures above 30 °C if the shear stress exceeds the long-term adhesion capacity. The low-frequency shear modulus of plasticised PVB is below 2 MPa at 50 °C, so permanent bending of laminated glass should be treated as a creep-sensitive design state rather than a purely elastic cold-forming operation. Published data for this specific cold-bent configuration is limited; project-specific full-size aging under EN ISO 12543-3 is required before production release.

In automotive windscreen production, Trosifol Clear is roll-fed in 0.76 mm and 0.38 mm formats; the cut interlayer is placed between a tin-side-oriented pair of curved glass plies with an edge overhang of 2 mm to 5 mm. The sandwich undergoes de-ionized water washing, IR preheating to 60 °C to 90 °C, nip-roller de-airing or vacuum bagging with residual pressure below 40 mbar, and autoclave bonding at 13 bar to 14 bar and 135 °C to 140 °C. Dwell for a single windscreen is normally 60 min to 120 min after the core reaches autoclave temperature; thin glass pairs occupy the low end, while thicker asymmetrical sidelites occupy the high end. After lamination, the edge is trimmed flush, and the part is inspected against ECE R43, GB 9656, JIS R3211, or ANSI/SAE Z26.1 impact and fragmentation requirements. Pummel adhesion is controlled between 3 and 7 because excessive adhesion reduces impact energy dissipation through interlayer delamination, while insufficient adhesion causes glass detachment in penetration testing.

Trosifol Clear is not designed as an acoustic interlayer; for windshields requiring transmission-loss improvement beyond standard monolithic glass in the coincidence region, the processor substitutes a multilayer acoustic PVB grade. This grade is also not wedge-shaped, so it cannot be used for head-up display windshields unless the wedged optical geometry is generated elsewhere in the glass or by another interlayer system. These are operational boundaries, not defects: the clear grade is optimised for impact resistance, optical clarity, and stable automotive adhesion.

When PVB Replaces EVA Encapsulants in Crystalline and Thin-Film Modules

PVB-based encapsulation in glass-glass photovoltaic modules uses Trosifol Clear as a thermoplastic encapsulant that requires no peroxide curing step. The lamination cycle in a vacuum laminator is run at a module surface temperature of 135 °C to 150 °C for 10 min to 20 min; the film softens and flows into the cell interstices, then gains structural properties on cooling. Compared with EVA, the PVB cycle must control edge bleed more tightly, because the thermoplastic melt can migrate under pressure and reduce edge cross-section. Chilled press plates or staged cooling are used before the module leaves the laminator. The encapsulation protocol is validated under IEC 61215-2:2021 and IEC 61730-2:2016, with extended damp heat at 85 °C and 85% RH for 1000 h used to detect adhesion loss and cell corrosion. Because PVB is hygroscopic, the glass edge must be sealed with butyl or edge tape after trimming; moisture ingress through an unsealed edge will produce edge cloud and delamination under damp heat. Terminal components include building-integrated photovoltaic spandrels, overhead BIPV canopies, and glass-glass modules where the rear glass provides structural support.

Lamination speed in PV module production depends on the time required to bring the cell surface to the target temperature, not on a chemical cure time. Unlike EVA, Trosifol Clear does not generate acetic acid during crosslinking, but it does demand lower ambient humidity during roll storage and lay-up. For high-volume thin-film backsheet configurations, published data for this specific product is limited, so qualification runs under IEC 61215-2 are necessary before converting an existing EVA line to PVB encapsulation.

When attack-rated glazing is specified without polycarbonate reinforcement, Trosifol Clear is stacked between multiple glass plies to increase energy absorption and post-fracture retention. A representative manual-attack build-up uses 6 mm glass / 1.52 mm Clear / 6 mm glass / 1.52 mm Clear / 6 mm glass, but the exact build-up is validated by EN 356:1999 or EN 1063:1999 performance testing rather than by predictive interlayer thickness alone. Multi-ply stacks require extended de-airing because the central PVB layers do not see the glass surface texture directly; residual pressure is held below 40 mbar for at least 20 min before heating. Autoclave dwell for five-glass/four-interlayer stack-ups is typically 180 min to 240 min after core temperature reaches 140 °C. Edge overhang is kept from 3 mm to 5 mm, and the finished edge must be inspected for microvoids that can nucleate moisture ingress under manual-attack test conditions.

Trosifol Clear has lower shear modulus than ionoplast interlayers; at 50 °C the post-breakage deflection of a large security panel increases relative to ionoplast systems. For overhead or continuously loaded anti-intrusion glazing, an ionoplast or composite interlayer is substituted. This is not a process defect but a material selection boundary: standard PVB is used where impact energy absorption and adhesion stability dominate, while stiff ionoplast is used where edge retention and lower creep under sustained load are required.

The following standard designations apply across the application set:

Does Edge Cloud Control Limit the Use of Clear PVB in High-Humidity Interior Applications?

Interior partitions, door leaves, display cases, and glass furniture use Trosifol Clear where the safety-glass classification must be achieved without introducing a tinted interlayer. The clear PVB absorbs UV below 380 nm and maintains luminous transmittance above 88% on a 3 mm/0.76 mm/3 mm laminate; haze remains below 0.5% when the film is properly de-aired. Edge cloud is the main production risk: because the film is hygroscopic, cut edges wick moisture from high-RH interior air. The interlayer is recessed 1 mm to 2 mm from the visible glass edge and, for bathrooms, pool enclosures, or air-conditioned art display vitrines, a moisture-cure silicone edge sealant is applied after edge finishing. Lamination for small-format interior glass is often run in a vacuum bag or convection autoclave at 12 bar and 135 °C; low-volume processors can use a bag-only cycle with a longer cold soak, but edge de-airing is less robust and optical rejection rate rises.

Interior glass is frequently required to comply with EN 12600, EN ISO 12543-2, or local human-impact codes, and the interlayer must remain visually stable under UV exposure from retail display lighting. Yellowing performance is assessed by ISO 4892-2; the PVB chemistry is more resistant to UV than aliphatic clear coatings but must still be protected from long-term edge moisture. Tin-side orientation remains critical in frameless interior partitions because tin-side surface chemistry can reduce adhesion and cause local delamination at the visible edge when the interlayer is recessed too far.

For rail vehicle side windows and marine glazing, Trosifol Clear is laminated between chemically or thermally toughened glass to provide spall retention and penetration resistance under vibration and cyclic pressure loading. Interlayer thicknesses of 1.52 mm or 2.28 mm are usually selected; the processing floor is held below 28% RH, and the cut interlayer is assembled with an edge overhang of 2 mm to 5 mm to prevent edge pull-in during de-airing. Autoclave bonding at 14 bar and 140 °C with a dwell of 120 min to 180 min is typical for thicker, multi-layer builds. Compliance for rail glass is assessed under EN 15152; fire-safety submittals under EN 45545-2 require additional interlayer chemistry, because Trosifol Clear alone does not provide the char and intumescent behaviour of fire-resistant PVB systems.