The case about adhesives for automobiles
From the perspectives of working parts and functions during the manufacturing process, the adhesives for automobiles can be classified into five types including solder adhesive, coating adhesive, automotive interior adhesive, Assembly components adhesive and Special technology adhesive. The introduction about different automotive adhesives is below.
Application about solder technologies
The sealant is applied to replace spot welding and decrease the welding spots. It can strengthen the structure, seal to prevent corrosion and reduce vibration and noise. It also has a good tack on oily steel plate. The product will cure under the condition of vehicle body painting, because there is no specialized thermal curing equipment. If the result is not affected by cleaning solution, phosphating solution and the quality of electrophoretic paint. The main products are below.
The product is applied to curled structures such as car doors, engine hood and decklid. The viscosity is high, which can replace the spot welding structure. This adhesive is one-component epoxy resin. The usage of each vehicle is 200g.
(2)Spot welding sealant
The product is applied to the lap of steel plate welding in advance. The spot welding can ensure the sealing to prevent corrosion. It is necessary to use spot welding sealant in those parts that is difficult to use solder sealant after assembling.
(3)Expansion damping adhesive
The adhesive is applied to car door between the outer plate and the inner one and vehicle body outer panel. It consists of synthetic rubber or resin with blowing agent. After curing expansion, the product can combine outer panel and stiffeners together to reduce vibration and noise. Each Dongfeng MotorEQ1030 uses 400g adhesive.
Coating adhesives are widely used in vehicles even though the types is few.
Data of each vehicle:Each truck and car would use about 2kg and 5kg respectively. These adhesives include soldering seam sealant and stone crash protection coating. The ingredient of substrates is PVC plastisol. Although there are many differences between two adhesives, the products can finish the mechanical adhesion and spray coating.
(1)Soldering seam sealant has excellent thixotropy. If reaching a certain thickness, it will keep edges and corners without flow. After heating plasticization, the adhesive layer has elastic property and smooth surface without crack. Soldering seam sealant is applied to automotive sealing, leakage and anti-corrosion.
(2)Stone crash protection coating is applied to automotive chassis, which could relief the impact from stones and gravels, improving chassis and corrosionresistance. Meanwhile, it can reduce interior noise and improve customers’ comfort.
Automotive interior adhesive
There are many different materials in automotive interior. So it is hard to conclude an united adhesive for various automobiles. There are some important products below.
(1)Vehicle roof adhesive
The product is applied to bond soft roof materials with vehicle roof, which could improve beauty inside the vehicle. It is solventneoprene with high primary viscosity. The product can satisfy the manufacturing requirements without discolouring and shedding phenomenon.
(2)Butyl sealing adhesive tape
Combined with butyl rubber and tackifing resin, the product is pressed into tape. It has good tack to bond steel panel and waterproof membrane with long-term viscoelasticity and sealing property. The product is main applied to bond and seal waterproof membrane with car door inner panel in case of rain infiltration. Each car door uses about 2-meter tape.
(3)High-frequency heat adhesive
Vehicle high-frequency heat adhesive is modified polyacrylic emulsion. During molding fender apron of car door, please put the fiber pad soaked in adhesive under the high-frequency electric field. Then the adhesive layer will melt in short period and bond PVC foam under the stated pressure.
The adhesive is made of polyurethane. It is applied with cleaning agent,paint surface/glass primer. It has good properties of high shear strength, excellent elastic property and sealing effect, which can integrate the glass and vehicle body to improve the vehicle safety. Each vehicle uses 1.2kg adhesive by the example of FuKang car.
Assembly components adhesive
The adhesive and sealant are widely used in automobile engine, gearbox and chassisassembling. They are applied to various plane connection and seal trepanning joint. The adhesive can prevent the leakage of oil, water, gas and bolt looseness. The adhesives include anaerobic adhesive, silicone sealant and etc..
The adhesive has many characteristics, such as easy coating process, quick curing rate and excellent sealing property. According to different requirements, there are three methods including coating live, pre-coating and infiltration. Among these, pre-coating encapsulated anaerobic adhesive is very suitable for lots of fittings on automobiles. According to the annual output of automobiles in our company, the usage of adhesive is about 2 tons.
It is applied to plane sealing well instead of filler sheet. The product also has many good properties of the excellent elasticity of adhesive layer, oil resistance, heat resistance, aging resistance, easy coating process and good tearability.
Special technology adhesive
Various adhesives are applied to the manufacturing process of automobiles, such as adhesives for disk brake pad which can bond brake shoe and friction discs. This adhesive is made of modified phenolic resin as main ingredient, which can replace riveting because of its high viscosity. It can reduce noise and prolong the working life of friction discs. Filter adhesive is applied to the manufacturing process of filtering cartridge, which is tackifing resin strengtheningPVC plastisol. The adhesive has many good properties of medium viscosity, excellent technology and satisfying the requirements on assembling line. Moreover, the impregnant is applied to plug micropores and repair the flaw of powder metallurgy articles, engine block and engine cover. During automobiles assembly process, the pressure sensitive adhesive tape, helping to fix the components, can prevent pollution and damage. The synthetic resin adhesive for casting contains three resins including phenolic resin, furan resin and a little modified urea-formaldehyde resin. This adhesive is widely used in the process of casting engine block and engine cover.