▶ Core Performance Requirements of Automotive Glass Sealant

Automotive glass sealant directly affects driving safety during glass installation and is exposed to complex outdoor conditions for extended periods. Its performance must meet automotive industry-specific standards (such as GB/T 13477), with core indicators significantly higher than ordinary glass sealant. Key requirements are as follows:

1. High Structural Bond Strength: Structural polyurethane sealant with a tensile shear strength ≥6MPa and a tensile strength ≥10MPa. After bonding to the glass and vehicle body, it can withstand vibrations, sudden braking, and bumps during vehicle operation, preventing glass detachment.

2. Excellent Vibration Fatigue Resistance: Maintaining an elongation at break of over 300% after curing, it can withstand long-term high-frequency vibrations of the vehicle body without cracking or delamination, with a service life ≥8 years.

3. Wide Temperature Range Weather Resistance: Adaptable to various weather conditions. Within a temperature range of 40℃ to 120℃, it remains brittle at low temperatures in the north and does not soften or sag at high temperatures in the south. It offers long-term resistance to UV rays, rain, and ozone; the adhesive layer does not powder, yellow, or peel off.

4. Excellent sealing and waterproofing: After curing, the adhesive layer forms a continuous, gapless sealing barrier with a waterproof rating of IP67 or higher, preventing rainwater, dust, and moisture from penetrating through gaps between the glass and the car body, thus avoiding mold growth in the interior and rust on the metal body.

5. Good application compatibility: Single-component adhesives are easy to extrude without interruption, and quickly form initial tack after application (10-20 minutes at room temperature), facilitating glass positioning; two-component adhesives can be applied continuously and automatically, compatible with original equipment manufacturer (OEM) production lines.

6. High adhesion to substrates: No additional primer is required (except for some low surface energy materials); it firmly bonds to automotive tempered glass, cold-rolled steel/aluminum alloy car bodies, and headlight plastic housings without delamination or bubbling.

7. Environmentally friendly and low-carbon. VOC: Meets automotive interior environmental standards; the adhesive layer has no irritating odor and does not release harmful gases after curing, ensuring a safe driving environment.

▶ Core Construction Steps (After-sales manual construction, windshield replacement as an example)

Before Construction: Old Adhesive Removal + Substrate Treatment (Most Critical Step)

1. Remove Old Adhesive: Use a special scraper to completely remove the old adhesive layer from the vehicle's glass frame, leaving a 0.5-1mm old adhesive base (to improve the adhesion between the new adhesive and the substrate), avoiding damage to the vehicle's metal body;

2. Degreasing and Drying: Wipe the vehicle's glass frame and the glass bonding surface with isopropyl alcohol/a special degreaser to thoroughly remove oil, wax, and dust, ensuring the surface is dry (no water stains, no moisture). Dampness will cause the adhesive layer to bubble and cure poorly;

3. Primer Application: If the vehicle's bonding surface is aluminum alloy or low surface energy plastic, a special primer must be applied and allowed to dry for 5-10 minutes before applying the adhesive to improve bonding strength.

4. During Construction: Applying Adhesive + Glass Positioning

1. Applying Adhesive: Load the single-component glass adhesive into a dedicated caulking gun. Cut the nozzle at a 45° angle and apply the adhesive continuously and evenly along the glass frame of the vehicle body. The adhesive layer should be triangular (8-10mm wide, 3-5mm thick), without any breaks or gaps, and avoid incorporating air into the adhesive layer.

2. Glass Positioning: Immediately after applying the adhesive, attach the glass to the vehicle body frame and secure it with a dedicated clamp. Gently press the glass to ensure the adhesive layer adheres fully to the glass and vehicle body. Adjust the glass position until precise, maintaining pressure with the clamp until the adhesive layer initially cures.

5. Post-Construction: Curing and Finishing

1. Curing Waiting: Single-component polyurethane glass adhesive requires 1-2 hours for initial curing at room temperature and 24-48 hours for complete curing. During curing, do not move the vehicle or remove the clamps to avoid glass displacement. Before complete curing, avoid water contact, rain, and external impacts on the adhesive layer.

2. Vehicle Rest: After the windshield is bonded, it is recommended to let the vehicle rest for 24 hours before driving. Avoid high-speed driving and sudden braking to prevent the glass from detaching before the adhesive layer has fully cured.

3. Adhesive Layer Finishing: Before the adhesive layer is fully cured, wipe off excess adhesive from the glass edges with a damp cloth to ensure a neat and adherent finish. After curing, remove excess adhesive with a special adhesive remover to avoid scratching the glass.

▶ Application Scenarios: