| HS Code | 188142 |
| Product Name | Saflex Horizon Vision |
| Manufacturer | Eastman Chemical Company |
| Material | Plasticized polyvinyl butyral (PVB) interlayer |
| Product Form | Interlayer film supplied in rolls |
| Primary Application | Laminated glass for architectural and structural glazing |
| Optical Quality | Ultra-clear, water-white transparency |
| Haze Level | Very low haze, typically ≤0.3% |
| Visible Light Transmission | High, typically greater than 90% in laminated glass |
| Uv Light Blockage | Blocks more than 99% of ultraviolet light |
| Color Neutrality | Neutral and colorless for maximum visual clarity |
| Adhesion To Glass | Provides strong adhesion for durable laminated safety glass |
| Impact Resistance | Enhances impact resistance and glass retention after breakage |
| Thickness Options | Available in standard PVB thicknesses including 0.38 mm, 0.76 mm, and 1.52 mm |
| Processing Compatibility | Compatible with autoclave lamination processes and standard glass laminating equipment |
| Durability | Resists yellowing, moisture ingress, and long-term optical degradation |
As an accredited Saflex Horizon Vision factory, we enforce strict quality protocols—every batch undergoes rigorous testing to ensure consistent efficacy and safety standards.
| Packing | Saflex Horizon Vision PVB interlayer is supplied as protective rolls in sealed moisture-barrier packaging, with a typical quantity of 25 kg per carton. |
| Container Loading (20′ FCL) | Saflex Horizon Vision loaded securely in 20′ FCL, palletized, protected from moisture, ensuring safe transport and intact delivery. |
| Shipping | Shipping: Non-hazardous, moisture-sensitive PVB sheeting. Pack flat in sealed moisture-barrier packaging with desiccant, protected from crushing and temperature extremes. Keep dry; avoid direct sunlight and sharp folds. Transport in standard covered trailers or containers, using appropriate lifting equipment, and handle carefully to prevent edge damage. |
| Storage | Store Saflex Horizon Vision in its original, unopened packaging in a cool, dry, well-ventilated area away from direct sunlight, heat sources, and moisture. Maintain stable temperatures between 10–30°C (50–86°F). Keep rolls flat or upright as supplied, protected from dust, mechanical damage, and water exposure. Use within recommended shelf life. |
| Shelf Life | Store in original packaging in cool, dry conditions. Shelf life is 24 months from date of manufacture. |
In laminated HUD windshield production, the chief optical defect corrected by a wedge-shaped polyvinyl butyral interlayer is ghost-image separation between the primary and secondary reflections of the virtual image. Saflex Horizon Vision is introduced as a plasticized PVB sheet with a controlled thickness gradient along the vertical HUD projection axis. The asymmetric cross-section intentionally changes the relative angle between the outer and inner glass plies so that the reflected images coincide at the driver’s eye position. Because the wedge angle is not a universal constant, the glass laminator must receive from the optical design team a wedge-angle specification tied to installation angle, windshield thickness, and HUD focal length. The interlayer is conditioned at 20–23 °C and 23–28% RH until Karl Fischer titration confirms moisture content in the range of 0.42–0.48 wt%. Storage outside these limits, particularly at RH above 60%, requires pre-conditioning before interlayer cutting. Material outside the moisture window can produce edge creep at low moisture or insufficient glass adhesion at high moisture. Lamination proceeds through vacuum de-airing at 0.6–0.8 bar absolute, followed by autoclave treatment at 10–13 bar and 130–140 °C for 60–120 min. The temperature and pressure ramp must be profiled to preserve the wedge profile; excessive heating at the thin edge can locally reduce the thickness gradient, while insufficient dwell can leave edge voids. Production-scale lines use roll nip de-airing only if the wedge direction is not distorted by the nip pressure gradient. Cutting and layup must follow the supplier’s directional marking, because reversing the sheet or flipping the roll does not simply reverse the optical correction and may place the thick edge in the wrong HUD zone. Safety glazing compliance is assessed under ECE R43 and FMVSS 205, while HUD optical performance is validated with SAE J1757-based virtual-image acceptance criteria and OEM-specific ghost image limits.
| Test domain | Method or standard | Representative acceptance criterion |
|---|---|---|
| Safety glazing classification | ECE R43, FMVSS 205, GB 9656 | Laminated windshield status |
| Luminous transmittance | ISO 13468-1 | ≥70% in driver’s vision zone |
| Haze | ASTM D1003 | ≤1.5% for interlayer film |
| Moisture content | Karl Fischer titration | 0.42–0.48 wt% before layup |
| Wedge angle profile | Laser profilometry, supplier certificate | OEM HUD design value; directional tolerance |
| HUD ghost image | SAE J1757, OEM optical acceptance | Virtual image separation below OEM threshold |
| Sound transmission loss | ISO 16940, ISO 10140-2 | OEM frequency-band targets |
The combination of a wedge PVB layer and an acoustic PVB core introduces a viscosity mismatch that can reduce the effective wedge angle during autoclave flow if the pressure ramp is not controlled. Acoustic trilayer stacks for premium passenger vehicles place the wedge interlayer on the outer glass side and a softer acoustic interlayer at the core, with a final PVB layer against the inner glass. The elastic and loss moduli of the acoustic core differ from those of the wedge layer at 130–140 °C, as measured by dynamic mechanical analysis at 1 Hz, producing differential squeeze flow that shifts resin toward the windshield edges. Laminators typically reduce pressure ramp to the lower end of the 10–13 bar envelope and hold temperature at 135 °C for the full dwell instead of using a rapid heat-up. Laser thickness scanning of the laminated edge at 5–10 mm intervals after autoclave is used to confirm that the wedge profile has not washed out. Sound transmission performance is not inferred from the wedge interlayer alone; laboratory measurements must follow ISO 16940 and ISO 10140-2, with the coincident dip in acoustic transmission compared against the OEM target band. When acoustic targets and HUD wedge requirements conflict on a batch, the line must reject based on the optical profile because the wedge angle is the functional requirement for HUD safety-relevant display readability. Published data for the specific viscosity interaction of Saflex Horizon Vision with co-laminated acoustic PVB is limited; therefore, a two-level factorial trial across temperature and ramp rate is required before serial production, and first-article parts should be cross-sectioned to measure wedge retention microscopically.
Mechanistically, the thickness gradient in a HUD wedge interlayer does not always remain confined to the HUD projection area when the windshield carries a forward-facing camera behind the painted black band. The wedge start line may intersect the camera aperture if the camera is mounted close to the HUD zone, and any vertical prism error across the camera window can shift the optical axis seen by the image sensor. The laminator must therefore define a wedge-free or wedge-transition zone with a positional tolerance often established at ±2 mm during line trials relative to the ceramic black print line, verified on the cut interlayer using transmitted-light edge detection. Optical distortion in the camera window is measured after lamination by a phase-shifting interferometer or a scanning moiré system, with acceptance indices referenced to the vehicle camera calibration procedure rather than generic glass flatness values. If the camera and HUD share a single continuous wedge profile without a transition zone, the resulting prism deviation can exceed the calibration range of lane-keeping and automatic emergency braking algorithms at highway speeds. Production experience shows that interlayer cutting tolerance and glass print registration are the dominant batch-to-batch sources of camera-zone prism drift; autoclave flow is a secondary contributor when the vacuum bag is not constrained by edge clips. For this reason, camera-zone wedge alignment is treated as a separate in-process control from visible HUD ghost image measurement.
Cold bending of the laminated windshield into a frame or body opening after autoclave introduces non-uniform in-plane stress that interacts with the wedge interlayer thickness profile. In large-format electric vehicle windshields, the glass plies may be sag-bent to a base curvature and then cold-bent an additional 3–10 mm at assembly, which changes the local angle between the outer and inner surfaces and therefore modifies the required wedge compensation. The wedge angle selected at the HUD optical design stage must be verified against the final assembled curvature, not the free-state autoclave curvature. Finite-element simulation of the glass bending stress and interlayer shear transfer is used to map edge stress and confirm that the thin edge of the wedge interlayer is not subjected to excessive tensile strain. At the production line, cold bending is performed on a frame fixture with controlled insertion speed, and the laminated edge is inspected for interlayer delamination using high-frequency ultrasonic scanning. The shear modulus of plasticized PVB at cockpit temperatures is rate-dependent; therefore, cold bending at low workshop temperature may require a preheated fixture to avoid a sudden stress concentration at the wedge-edge transition. Optical performance after cold bending is rechecked with a HUD virtual-image rig, because a uniform geometric change in the glass may still shift the ghost-image threshold if the HUD projector is mounted on a common bracket with the steering column. Compliance remains anchored to ECE R43 and FMVSS 205 for the safety glazing substrate, but the HUD optical acceptance must be validated on a representative body-in-white assembly rather than on a free-state window.
Silver-based infrared-reflective coatings on the inner surface of the outer glass ply are common in HUD-equipped vehicles because solar load reduction through the windshield reduces air-conditioning demand and lowers dashboard surface temperature. Saflex Horizon Vision must provide controlled adhesion to the coated glass without carrying plasticizer or additives that migrate into the silver stack and increase sheet resistance. Coating compatibility is evaluated after lamination by edge strip adhesion and by environmental aging under sustained heat and humidity; edge seal durability is tested with cyclic neutral salt spray according to ISO 9227 or equivalent OEM test procedures. The moisture sensitivity of PVB means that edge moisture ingress in service can locally plasticize the interlayer and shift the wedge profile at the windshield periphery, although the central HUD zone is not directly exposed. Windshield assemblers often apply an edge sealant and require a minimum edge distance between the PVB cut edge and the coated glass edge to prevent silver dissolution. Lamination of coated glass may use a lower autoclave temperature near 130 °C for thermally sensitive coated-glass stacks, but the temperature reduction must be verified by wedge-profile retention measurement because lower temperature can increase residual edge voids if the de-airing step is insufficient. The combined system is qualified as a complete windshield construction, not as an isolated interlayer, because the coating’s tin oxide or zinc oxide base layers alter acid-base surface energetics and final peel adhesion.
Replacement HUD windshields are not a simple drop-in because the wedge profile is specific to the original equipment projector, windshield installation angle, and trim height. Aftermarket laminators must either reverse-engineer the OEM wedge map by scanning the original windshield with a laser profilometer or purchase a licensed wedge interlayer matched to the vehicle program. Published wedge-angle data for most replacement applications is limited, so the reverse-engineering process consists of full-surface thickness mapping of the de-laminated original after interlayer removal, followed by ray-tracing verification on a HUD test rig. The interlayer is then cut and oriented with the same directional convention as the original component; reversing the wedge direction may produce an increased ghost-image separation in some HUD configurations. This segment remains constrained by supply-chain access to exact product specifications, and internal quality records must retain thickness maps for batch traceability.
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Saflex Horizon Vision is a polyvinyl butyral (PVB) interlayer developed for automotive laminated glass in which the windshield or side window functions as the optical combiner for a head-up display (HUD). The product designation is Saflex Horizon Vision; no additional public sub-model designations are documented. Unlike uniform-thickness PVB interlayers, Saflex Horizon Vision is produced as a wedge-profile sheet whose thickness changes across the width or height of the windshield opening. The position, direction, and magnitude of that wedge are mapped to the HUD projector geometry and the installed windshield angle. The product is supplied on the same baseline gauge system used for other Saflex PVB interlayers, with nominal starting thicknesses of 0.38 mm and 0.76 mm; custom wedge profiles are generated from those baselines. Published product-specific property sheets for Saflex Horizon Vision are limited outside OEM-controlled documentation, but the bulk polymer properties follow the PVB family envelope.
PVB interlayers of this class typically exhibit a density of 1.07 g/cm³ at 23°C when tested according to ISO 1183-1:2019. Refractive index measured by ISO 489:2022 is approximately 1.48, which is close to the refractive index of soda-lime glass at 1.52. Tensile strength determined by ASTM D638-14 generally falls between 20 MPa and 35 MPa for plasticized film, and elongation at break commonly exceeds 200%. Dynamic mechanical analysis following ISO 6721-12:2022 places the glass transition region between 25°C and 35°C depending on plasticizer type and moisture content. These values describe unfilled PVB resin; the lateral thickness gradient does not change the bulk polymer chemistry but alters the optical path through the laminate.
| Property | Typical PVB Value | Test Method |
|---|---|---|
| Density | 1.07 g/cm³ | ISO 1183-1:2019 |
| Refractive index | 1.48 | ISO 489:2022 |
| Tensile strength | 20–35 MPa | ASTM D638-14 |
| Elongation at break | >200% | ASTM D638-14 |
| Glass transition region | 25–35°C | ISO 6721-12:2022 |
The plasticizer system in PVB interlayers influences flow behavior during autoclave lamination and the temperature dependence of wedge-angle retention. Common plasticizer chemistries include triethylene glycol bis(2-ethylhexanoate) and related esters. Plasticizer content for Saflex Horizon Vision is not published, but production-scale PVB balances tensile strength, glass transition, and adhesion. A higher plasticizer fraction reduces melt viscosity and increases the risk of wedge-profile washout during autoclave bonding, while a lower plasticizer fraction can produce excessive stiffness and poor glass wet-out. The material is therefore manufactured within a narrow melt-flow envelope and is shipped with a specified moisture limit. Quality control uses Fourier-transform infrared spectroscopy and gel permeation chromatography to verify resin hydroxyl content and molecular weight distribution, which control the adhesion reaction with glass and the response to humidity during storage.
Compounding of PVB for wedge interlayers is performed on twin-screw extruders with downstream flat-die film systems. Local thickness gradient is created either by die-lip profiling or by post-extrusion stretching under controlled thermal conditions. Thickness scanning at the extruder uses beta-gauge sensors to detect local basis-weight excursions before the sheet is wound into rolls. The direction of the wedge is recorded on the roll and must be tracked through slitting, cutting, and lay-up. On production lines, an inverted PVB wedge is a known failure mode because it increases ghost-image separation rather than reducing it.
HUD ghosting arises when the projected image is partially reflected by both the inner and the outer glass surfaces of the windshield. In a windshield formed from symmetrical-thickness PVB, the two reflected images are separated by a small but visible angular offset. The primary image is formed by reflection from the inner glass surface, while the secondary image is reflected from the outer glass surface after passing through the glass, interlayer, and second glass ply. The offset is governed by glass thickness, refractive indices, and the local angle of incidence. Saflex Horizon Vision addresses this by introducing a controlled wedge angle between the glass plies. The wedge changes the path length difference and effectively brings the primary and secondary reflected images into closer angular alignment. The wedge angle is not a single commercial value; it is an integration parameter calculated from the HUD projector geometry, windshield installation angle, and driver eye box location. In production, the direction of the wedge is marked on the PVB sheet because an inverted orientation would increase ghost-image separation rather than reduce it.
Wedge-profile PVB sheet introduces a process constraint that is less severe with uniform-thickness interlayers. The lamination process must preserve the pre-formed wedge angle while achieving the required glass-to-PVB adhesion. Production-scale windshield laminating lines typically process PVB in clean lay-up rooms maintained at 18°C to 22°C and 25–30% relative humidity. Assembled windshields are pre-pressed through heated rollers or vacuum bags to remove air before autoclave bonding. Autoclave cycles for PVB windshields generally operate at 130°C to 140°C and 1.0 MPa to 1.5 MPa with hold times of 60 min to 120 min. Temperature above 150°C can lead to plasticizer exudation at the edges, while peak pressure before even glass heating can cause local delamination or wedge-angle washout. On production autoclaves, pressure ramp rate and internal air temperature are monitored with load-cell pressure transmitters and thermocouple arrays near the loaded glass packs.
Moisture control is critical because PVB is hygroscopic and moisture affects both adhesion and flow. Exposure to relative humidity above 60% without re-drying can produce moisture-related defects such as bubbles, poor adhesion, and variable melt flow. On production lines, the material is often conditioned in a climate-controlled lay-up room for 24 h to 72 h before assembly. Incompatible cleaning agents containing amines or high-pH formulations may plasticize the PVB surface and shift adhesion away from the pummel-test range expected by the OEM. Laminated assemblies are normally subjected to bake adhesion tests, optical distortion scanning, and cross-section thickness profiling after autoclaving. The wedge angle is not directly measured from the PVB sheet alone; it is measured from the laminated windshield by thickness difference across the optical zone or by optical double-image testing on a HUD-specific fixture.
After autoclaving, the effective wedge angle is verified not by mechanical caliper alone but by optical methods. A laminated-glass wedge of 0.1 mrad corresponds to a thickness difference of 0.1 mm per 1 m of linear path; practical HUD wedges are often specified as local thickness slopes over the optical zone. Measurement systems include white-light interferometry for edge profile, scanning laser thickness gauges, and HUD projector-based double-image test benches. The double-image test bench uses a collimated light source and a retroreflective target to quantify the angular displacement between the primary and ghost images at defined eye-box points. While no single public standard defines the acceptable HUD double-image angle, the measurement principle follows the same geometric optics used for windshield optical distortion testing. The key process risk is wedge-angle washout: if autoclave temperature and pressure allow the PVB to flow, the local slope can be reduced below the lower control limit. Production lines that process HUD PVB typically verify wedge angle by measuring cross-thickness profile at three to five positions across the HUD optical zone and comparing the slope to the OEM drawing.
Wedge-profile PVB rolls must be stored flat, in the original moisture-barrier packaging, and at controlled temperature below 25°C. Exposure to relative humidity above 60% without re-drying can produce moisture-related defects such as bubbles, poor adhesion, and variable melt flow. On production lines, the material is often conditioned in a climate-controlled lay-up room for 24 h to 72 h before assembly. Batch-to-batch consistency in wedge angle is monitored by ultrasonic thickness scanning and melt-flow index testing. Because the PVB sheet is directional, roll unwind direction and printed orientation marks must match the glass-bending direction and the HUD projector position.
The required wedge angle increases as the windshield installation angle becomes shallower relative to the HUD projector axis. A passenger car windshield with a design angle near 30° from horizontal may generate a different double-image offset than a truck windshield installed near 60°. For this reason, Saflex Horizon Vision is not supplied as a single universal wedge product; it is profiled according to the glass set, vehicle platform, and field-of-view requirements. The HUD eye box defines the region within which the driver’s head position can vary while the projected image remains legible. The wedge profile must maintain the ghost-image convergence across that entire eye box, not merely at the nominal design eye point. Local profile tolerance therefore becomes an input to windshield bending, PVB extrusion, and lamination. Published data for the exact tolerances of Saflex Horizon Vision is limited; OEM drawings typically define thickness difference over a specific optical zone rather than a single wedge angle.
Optical quality after lamination is evaluated using collimated light sources and HUD test projectors that measure the angular separation between the primary and ghost image at multiple points in the eye box. While general laminated-glass optical quality is addressed by regulatory standards such as ECE R43 for automotive glazing, the specific double-image acceptance threshold for HUD is usually defined in the vehicle manufacturer’s internal specification. The measurement equipment includes goniometric platforms and retroreflective targets. A residual double-image angle that is acceptable for a conventional windshield may not be acceptable for a HUD windshield because the projected symbology is high contrast and low angular tolerance.
Conventional PVB interlayers are manufactured with uniform thickness across the sheet and are specified primarily for adhesion, impact retention, and optical clarity. Acoustic PVB interlayers incorporate a soft core or higher-loss plasticizer system to increase sound transmission loss in the frequency range associated with windshield coincidence dip. Saflex Horizon Vision is functionally different in that its primary specification is optical wedge control rather than acoustic damping. It may be used in constructions where HUD imaging is required, and its difference from conventional PVB lies in the deliberate thickness gradient. The distinction is not a bulk polymer shift but a geometrical and processing difference: the PVB sheet must be oriented, the wedge direction must be verified, and the lamination cycle must be robust enough to avoid washing out the profile.
| Parameter | Conventional PVB | Saflex Horizon Vision wedge PVB | Acoustic PVB |
|---|---|---|---|
| Cross-section profile | Uniform thickness | OEM-specific wedge | Uniform thickness or multilayer |
| Primary function | Glass adhesion and impact resistance | HUD ghost-image control | Sound transmission loss |
| Typical baseline gauge | 0.38 mm, 0.76 mm | 0.38 mm, 0.76 mm | 0.38 mm, 0.76 mm |
| Wedge angle | Not applicable | OEM-specific; not a single published value | Not applicable |
| Processing orientation | Not directional | Directional relative to HUD projector | Not directional |
When HUD functionality is not required, conventional PVB remains the lower-complexity material for laminated glass. When acoustic comfort is the priority, acoustic PVB may be specified. Saflex Horizon Vision should be selected only after the HUD system integrator has provided the required wedge-angle map and eye-box dimensions, because the material cannot be post-corrected after lamination. In production, sheet orientation, glass-bending tolerance, and autoclave pressure ramp rate are the binding process variables.
In regulatory terms, the laminated windshield must still meet the applicable safety-glazing standard, such as ECE R43 or ANSI Z26.1, regardless of wedge profile. The wedge geometry does not remove the requirements for headform impact resistance, partial impact, or optical transmission. The HUD-specific wedge is therefore a functional addition to a safety interlayer rather than a replacement for conventional impact requirements.
