The so-called automotive structural adhesive refers to the high bonding strength, which can withstand the force as a structural member, and its bonding strength. For ordinary steel plates, the shear strength can be 20MPa, and the peel strength can be above 1.0MPa. This type of glue is usually modified epoxy resin. For example, FAW used CJ-1 structural glue to bond the engine middle cover and the front and rear reinforcement beams to replace welding, reduce solder joints, and solve the problem of solder pitting on the surface of the middle cover. , Improve the appearance quality of the car.
With the development of the automotive value chain, structural adhesives play an important role. The automotive industry continues to seek more practical and lower-cost ways to reduce vehicle weight, while improving automotive performance and customer satisfaction. The needs of the automotive market will point out the direction for the development of structural adhesives.
The main types of structural application adhesives commonly used in the automobile manufacturing process are as follows:
First, structural adhesive
The so-called automotive structural glue refers to the high bonding strength, which can withstand the force as a structural member, and its bonding strength. For ordinary steel plates, the shear strength can be 20MPa, and the peel strength can be above 1.0MPa. This type of glue is usually modified epoxy resin. For example, FAW used CJ-1 structural glue to bond the engine middle cover and the front and rear reinforcement beams to replace welding, reduce solder joints, and solve the problem of solder pitting on the surface of the middle cover. , Improve the appearance quality of the car.
Second, hemming glue
The so-called hemming structure is to combine the inner and outer panels by bonding and hemming. This structure eliminates spot welding pits, keeps the body smooth and beautiful, and improves the corrosion and rust resistance. . Most of the hemming glue needs to be heated to cure, and the bonding strength is high.
Three, expansion and vibration damping glue
Before the body is welded and assembled, the viscous paste-like shock-absorbing glue is applied (spread) on the reinforced beam or inner plate, and then assembled and welded. The shock absorber does not need to be separately equipped with heating and curing equipment, and usually it can meet the requirements by using the electrophoretic primer drying oven to heat curing. It not only increases the rigidity of the top cover, but also plays the role of shock absorption. For example, FAW CA6440 van-type door inner and outer panels and side walls use CB-1 shock-absorbing film to solve the noise problem.
Four, spot welding glue
Automobile bodies are generally welded by steel plates, so the existence of drying seams is inevitable. The application of spot welding glue guarantees the sealing quality. Its characteristics are fixed conductivity, good adhesion before curing, no pollution to the phosphating solution and electrophoresis solution, and no organic silicon substances.
Fifth, anti-stoning paint
When a car is driving fast, the floor, wheel cover, skirt, etc. will be impacted by the sand and gravel brought by the wheels, causing the coating to peel off. The steel plate is corroded to resist this impact and shock absorption. The bottom of the large car body must be coated with a layer of glue. Class. Hit damping paint. It is now used as a kind of material for automobile anti-stone attack, heat insulation and damping paint. ①Solvent type with asphalt as the main material. Asphalt-based coatings are inexpensive and require low construction conditions. They are suitable for undercoating on trucks and large passenger cars. Although there are still many automobile manufacturers applying them, they are gradually affected by water-based The trend of paint replacement. ②Water-based type with synthetic resin as the main material. Water-based paint is a new material developed in recent years. It uses acrylic emulsion as the base material and is composed of inorganic heat insulation fillers. It is non-toxic and non-combustible as its outstanding advantages. ③Solvent-free type with PVC resin as the main body. PVC undercarriage paint is the most widely used one. Its composition is like weld glue. It needs to be plasticized at 130-140℃ after spraying.
The damping and heat insulation sheets placed on the bottom of the car, the bottom of the truck cab, the front wall and the wheel cover are also made of asphalt, added with rubber powder and inorganic fillers, and used hot melt, self-adhesive or magnetic at the bottom. After the paint is dried, it is spread on the bottom plate, and is softened by heat when the middle coat or top coat is dried, and closely fits with the covered part, which has the effect of damping, insulating and preventing noise transmission.
