Shanghai, China -- Within the automotive industry, lightweight construction offers a solution to the development of more economical and more ecologically viable vehicles -- and adhesives have a vital role to play here, according to German adhesives and resin supplier Henkel.
The more steel components that are replaced by lighter materials such as aluminium, the more weight can be cut, and the greater is the saving in both fuel consumption and emissions.
Henkel adhesives aid the permanent bonding of different, lighter materials that cannot be thermally welded. In addition, the company says, its surface treatments offer the best possible results with sparing chemical input.
There is huge pressure on the automotive industry to manufacture light vehicles offering low fuel consumption values so as to reduce environmental burden. One way to help meet the challenge is to create the car body by pretreating and joining together components of lighter, albeit disparate materials.
Henkel says it is engaged in the development of its products and technologies to, for example, reduce production costs and material consumption for car makers, and to create a safe working environment.
For the driver, there are also safety advantages from adhesive-bonded joints, as these absorb a significant portion of the impact energy generated in an automobile crash.
Lightweight construction such as is used in Porsche 911 GT3 Cup racing cars comes from use of materials such as aluminium and composites, with composites based on carbon or glass fibre becoming increasingly important for modern high-performance applications, due in particular to their ability to offer low weight combined with high strength.
For mass-produced cars, injection processes such as resin transfer moulding are becoming widely used. For this, Henkel has developed a polyurethane-based composite matrix resin characterised by short curing and ease of use. This Loctite MAX2 not only cures significantly faster than standard epoxy resins, but during injection its lower viscosity also enables more efficient, gentler impregnation of the fibres.
The material produced is less brittle and characterised by its improved tear strength, so makes an important contribution to ensuring that composites can be mass-produced with good cost efficiency and process reliability.
A vehicle assembled using adhesive bonding produces better crash test results than a car that has been riveted or welded. "Because the bonded joint can deform in the event of impact, a portion of the crash energy is absorbed by that deformation work," explains Dr Stefan Kreiling, Hhead of Product Development Automotive Europe at Henkel.
The adhesive bonds increase the stiffness of the automobile, seal joint seams, reduce the number of welds and render cars more corrosion resistant. In addition, the speciality adhesives used in body construction and final assembly also help to reduce noise, claims Henkel.
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