New requirements for polyurethane materials in the development of the automotive industry (6)

In addition to good bonding strength and impact strength, the traditional one-component moisture-curing polyurethane windshield adhesive has the characteristics of aging resistance, low humidity resistance, fatigue resistance, water resistance and oil resistance, among which low temperature resistance and oil resistance are particularly protruding. In addition, it has the characteristics of convenient use, high bonding strength and good stacking performance. It is easy to use the bonding process in the assembly of window glass and body panels, which not only enhances the sealing performance, reduces the vibration, but also improves the body. The overall rigidity. It is usually used in combination with a cleaning agent, a glass primer, and a lacquer primer. The new polyurethane windshield glue eliminates the need for a glass primer. More than 95% of foreign automobile manufacturers use the direct bonding technology of window glass. This kind of technology is used in China's automobile production not only in medium and high-grade cars and luxury passenger cars, but also widely used in popular passenger cars, such as Hafei. Mini-vans produced by Kyrgyzstan.

At present, the raw materials of polyurethane adhesives are mainly imported from abroad. There are many manufacturers of polyurethane sealant for windshield abroad, mainly including: Essex and 3M in the US, Sunstar in Japan, Yokohama Rubber in Sekisui Chemical Co., Bostik and Teroson in Germany, and Sika in Switzerland. and many more.

The strength of the new high modulus glass polyurethane sealant is 2 times higher than the original. The high initial viscosity glass sealant avoids the sliding deviation of the glass. The low conductivity glass polyurethane sealant can improve the acceptance of the window type radio antenna. The effect is that the polyurethane sealant for pre-coated glass can simplify the installation process.

Polyurethane structural adhesives are used to bond luxury passenger car body panels, luggage compartment panels, front and rear skins and other body parts, eliminating the solder joints on the body skin surface and making the body structure smooth and smooth.

The development of the automotive industry requires lightweight components. In the past few years, the technology of replacing lightweight steel with high-strength engineering plastics has developed rapidly, such as the body made of glass fiber reinforced plastic (FRP) and sheet molding compound (SMC). Panels and exteriors (such as car roofs, cockpit covers, etc.) have been widely adopted in the United States, Europe, and Japan. However, FRP and SMC cannot be assembled with the body frame using traditional welding techniques, and bonding technology must be used. Therefore, the polyurethane bonding process will be more widely used in the future.

2, water-based polyurethane glue

Foam-backed vinyls for automotive interiors, fabrics bonded to fiberboard and other hard substrates have traditionally used solvent-based adhesives. However, with the increasingly strict environmental regulations, countries around the world have vigorously developed water-based adhesive upgrade products. High cost and high energy consumption are obstacles to the expansion of waterborne polyurethane adhesives. In recent years, solvent-based polyurethane adhesives have not been replaced. At present, developed countries are further working on water-based polyurethane adhesives to reduce costs and improve performance.

Water-based polyurethane adhesives contain no solvents and do not release formaldehyde and benzene. Therefore, they do not endanger the health of workers and do not harm the health of occupants. Waterborne polyurethane adhesive has excellent performance, water resistance, medium resistance, high bonding strength, stable storage, good film forming performance and non-flammability under low temperature environment, plus the advantages of safety and environmental protection, making it an aqueous adhesive. One of the main development directions. At present, more than 3 of the world's automotive roof lining adhesives belong to this category of products, and domestic car production is also adopting this technology. At present, this new type of environmentally friendly adhesive has been adopted in cars produced by domestic automakers such as FAW and SAIC.

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