Do you know the importance of polyurethane sealant for car windshields?

Windshield with adhesive can absorb vibration and impact, improve the overall performance of the car. Polyurethane windshield adhesive is an important product in the sealing process of automobile glass. According to statistics, at present, the adhesive of passenger car windshield glass, polyurethane sealant; More and more passenger cars, especially high-end luxury passenger cars manufacturers of windshield glass and side window glass bonding sealing has been promoted to implement polyurethane bonding technology.

1.Adhesive design requirements for windshield glass

(1) High strength and tear resistance.

(2) weather resistance and durability.

(3) Excellent sealing performance.

(4) The construction process is simple and the displacement time is short.

(5) Meet the overall rigidity of the car body, and increase the rate of change when the glass is broken.

According to the automobile industry standard QC/T 1024-2015 'single-component polyurethane sealant for automobiles' requirements, the basic performance of single-component polyurethane sealant for automobiles must meet the tensile strength ≥6.0MPa, and must pass the heat resistance, humidity and heat resistance, artificial climate accelerated aging (xenon arc lamp), water resistance and other aging performance test.

2.Comparison of properties of various materials

The common sealing materials of windshield glass mainly include traditional rubber strip, polysulfide sealant, silicone sealant, polyurethane sealant. The features and application scenarios of various materials are compared as follows:

(1) Traditional rubber strip: Low sealing performance, easy deformation; Application scenario: Commercial vehicles and rail vehicles are partially used.

(2) Polysulfide sealant: High viscosity, heavy odor; Application scenario: No longer applicable.

(3) Silicone sealant: Good weather resistance and durability, wide adhesion, low tensile strength; Application scenario: This parameter is applicable only to scenarios with a low security factor.

(4)Polyurethane sealant: with a variety of materials have excellent chemical glue relay; It can be cured by heating or at room temperature. It has good resistance to wear, water, oil, ozone, solvents, chemicals and mildew. At high temperature and high humidity, it is easy to hydrolyze and reduce the bonding strength. Application scenario: High strength bonding and sealing between various vehicles and vehicle bodies.

3.Polyurethane windshield sizing method

When sizing polyurethane sealant for windshield glass, it is important to pay attention to the 'three points of material, seven points of construction'. Good construction is an important guarantee that sealant products can fully play the excellent performance. Before sizing, it is necessary to test the adhesion of sealant and substrate, determine the bonding effect of sealant and substrate, and select the appropriate detergent and base coating agent.

Sizing process:

(1) Surface cleaning: improve the adhesion of polyurethane sealant and substrate.

(2) Apply base coating agent: improve the adhesion of polyurethane sealant and substrate.

(3) Sizing and installation: before sizing, the rubber nozzle needs to be cut into a triangular opening with a knife. 

The adhesive of automobile windshield glass is very important to the safe running of automobile. In the impact, the car windshield glass will absorb a huge impact, at the same time must be firmly glued to the car body, can not fly off from the car; When a traffic accident occurs, the windshield with strong adhesion must have enough strength to support and protect the safety of passengers, which puts forward high requirements for the sealant of the glass and the body.