Sealing Headlights

Water-Repellent and Temperature-Resistant Polyurethane Foams Ensure Excellent Headlight Sealing Protection

We offer efficient and flexible sealing solutions to meet your individual requirements for headlights that provide excellent protection against moisture, corrosion, and dust. Our two-component sealing foam is installed into the back-cap and compressed in the overall part construction of the vehicle light. Keeping moisture out and avoiding the risk of internal electronics corroding.

Even though headlights with xenon, LED and laser light technology now represent state-of-the-art vehicle lighting in many markets, there are still countries where cars are sold with conventional headlamps using lightbulbs. Our customers use FERMAPOR K31 two-component polyurethane foams for sealing these conventional headlights, which are characterized by excellent long-term behavior and very high resilience of the foam structure.


Tailor-Made Sealing Solutions for Headlights

Developed Individually for Your Specific Requirements

For sealing conventional headlights, FERMAPOR K31 two-component polyurethane foams offer excellent long-term behavior and very high resilience of the foam structure.

The back-cap on the back of the headlight can be opened and closed again at any time, e.g. to change the H7 bulb, without the sealing effect weakening, and the polyurethane foam can be easily compressed to compensate for component tolerances, thanks to the unique mixed-cell foam structure.

The different reaction phases of the sealing foam in the chronological sequence

Reference Material

  FERMAPOR K31-A-5555-1


Mixing ratio 4 : 1 2.3 : 1
Pot life 35 sec. 30 sec.
Tack-free time 4 min. 16 min.
Viscosity A component 55,000 mPas 70,000 mPas
Foam density 0.27 g/cm3 0.31 g/cm3
Hardness (Shore 00) 54 55
Temperature resistance from -40 to +80 °C from -40 to +80 °C
Pretreatment Primer P23 (solvent-based)
P13(water-based) or plasma
Primer P23 (solvent-based)
P13(water-based) or plasma

In addition to the reference products, we develop material systems according to your individual requirements. Influencing factors include pot life until start of foaming, curing time, and the viscosity, hardness, and adhesion properties.

Repeatedly Opening and Reclosing for Maintenance Purposes with Remaining Sealing Effect

The high resilience of the foam seal allows the components to be opened and reclosed repeatedly for maintenance purposes without the tightness deteriorating. After installation, the headlight is sealed, and the sensitive electronics are protected against splashing water and the effects of the weather.

Watch a video showing the foam compression process.

Cross-section of a polyurethane foam bead in a groove without compression.


Cross-section of a polyurethane foam bead in a groove. Compressing the foam gasket between approximately 30 - 60 % of the original height achieves the required degree of tightness in the installed condition.


DM 502 Mixing and Dosing System with 3-Axis Linear Robot and a Shuttle Table for Picking Headlight Back-Cap Parts

The reference configuration shown here for sealing the back-caps of headlights consists of our DM 502 mixing and dosing system uses an HE 3-axis linear robot, as well as a WT 1-LEVEL shuttle table for picking up parts. The two pick-up plates working in pendulum mode enable the workpieces fixed there to be picked up and processed in one plane. This makes it possible to guarantee continuous operation.

The placement and holding on the shuttle table of the headlight housing to be sealed is performed either by a machine operator, who can also check the parts for quality, or by a Pick & Place Robot. In such a case, an optionally installed camera or sensor system could carry out the quality control of the parts.

Flexible and Fully Automatic – According to Your Requirements

For sealing the headlights, FERMAPOR K31 thixotropic polyurethane sealing foam is applied through the nozzle of the CNC-controlled MK 825 PRO mixing head, in a high-precision and fully automatic process, onto the 2D or 3D application surface or into the groove of the component contour.

After the dosing cycle, the coupling point of the foam gasket closes almost seamlessly and is thus virtually invisible. Due to the uniform compression in the installed state, a high level of tightness is achieved over the entire contour of the back-caps.

For improved adhesion of the foam gasket to plastics such as PP or PE using plasma, we install an optional plasma nozzle on the rear of the CNC Y-axis in addition to the mixing head.

Even with short cycle times and high unit numbers, the material application process using the FIPFG method is carried out with high dosing precision and repeat accuracy. As a result, you achieve foam gaskets of uniformly high quality. This means that your sealed headlights can be processed rapidly, right through to final assembly. This saves time and money.

In addition, our fail-safe mixing and dosing system can be operated easily and intuitively without the need for extensive training. Due to the automatic logging of dosing program data, all process data can be traced and evaluated by the machine operator while production is running.