Automotive adhesives, sealants applications
From the perspective of the working parts and functions involved in the entire manufacturing process of the automobile, the automotive adhesives can be roughly classified into five major categories:
(1) Welding process glue
(2) Coating process glue
(3) Adhesive for interior parts
(4) Glue for assembly parts
(5) Special process glue

The welding process glue: This type of sealing adhesive replaces spot welding or reduces solder joints in the welding process, plays the role of reinforcing structure, sealing rust, vibration and noise reduction, general requirements and oil surface steel plate Good adhesion. Since there is no special heating and curing equipment in each station, it needs to be cured under the paint process of the body. Therefore, it is required to be neither affected by the cleaning liquid or the phosphating solution nor affect the quality of the electrophoretic paint.
Its main varieties are:
1.1 Folding glue
It is used in the crimping structure of the door, engine, cover, trunk lid, etc., and its bonding strength is high, which has completely replaced the spot welding structure. This type of rubber is currently commonly used in one-component epoxy resin, and the bicycle dosage is about 200g.
1.2 Spot welding sealant
It is pre-coated on the lap joint of steel plate welding, and the gap is filled after spot welding to ensure sealing and prevent rust. Spot weld sealants are indispensable for those parts that are masked and difficult to apply to the weld sealant after assembly.
1.3 expansion damping rubber
Such glue is often used between the inner and outer panels of the door, between the outer cover of the vehicle and the ribs. It is generally made of synthetic rubber or resin with foaming agent. After curing and expansion, it can combine the covering parts with the reinforcing ribs to play the role of vibration and noise reduction. The Dongfeng EQ1030 model has a capacity of 400g for bicycles.

The coating process with plastic: Although there are not many varieties, it is the largest type of car. Bicycle usage: about 2kg for trucks and more than 5kg for cars. There are mainly weld sealant and anti-stone coating. The base components are all PVC plastisol. Although the performance of each of them is different, the process requires mechanical coating or spraying by high-pressure coating equipment.
Comparison :
2.1 Weld sealant
It has a more prominent thixotropy, and it can maintain the edges and corners when a certain thickness is accumulated, and no runny is generated. After heating and plasticizing, the rubber layer is elastic, does not crack, and has a flat appearance, and can not cause discoloration in the middle coating and the top coating. Weld sealant plays a vital role in car sealing, leak prevention and rust prevention.
2.2 Anti-stone coating
Sprayed on the chassis of the car to cushion the impact of various objects such as sand and stone on the chassis at high speed, improve the corrosion resistance of the chassis and prolong the service life, and help reduce the noise inside the car and improve the comfort of the occupants.

The interior parts of the rubber: automotive interior parts of a wide variety of materials, different nature, different applications, so the use of plastic varieties are different, it is difficult to generalize.
Some of these important varieties are now introduced:
3.1 Car body roof glue
It is used to attach the soft ceiling material to the roof of the car to enhance the interior of the car. At present, the adhesives for this purpose in China are mainly solvent-based neoprene. The process and performance require high initial adhesion, meet the fast-paced needs of the body interior production line, and must not cause discoloration or shedding of the interior materials.
3.2 butyl sealing tape
It is extruded into a belt type by adding a tackifying resin to butyl rubber. Its characteristics are: easy to press the finger pressure, good adhesion to the steel plate and the waterproof film, and long-term retention of viscoelasticity and sealing. It is mainly used for the adhesive sealing of the waterproof film of the inner panel of the door to prevent rainwater from penetrating into the interior of the door. The amount of single door tape on the car is about 2m.
3.3 high frequency heat sealing glue
Fukang car uses high-frequency heat-sealing adhesive as modified acrylic emulsion. When forming the inner cover of the door, the fiberboard treated by dipping (about 30g) in advance is melted in a short time under the action of high-frequency electric field, and in the process Strong adhesion to PVC foam under specified pressure.
3.4 windshield glue
This kind of adhesive is usually made of polyurethane. It is used together with cleaning agent and lacquer/glass primer. It has high shear strength and outstanding elasticity. It can combine glass and body into one whole, enhance the rigidity of the body and ensure the sealing effect. Improve car safety. Take the Fukang sedan as an example, the bicycle usage is about 1.2kg.

Glue for parts and accessories: engine, gearbox, chassis assembly adhesive, sealant, its application is mainly reflected in various flat connections, the sealing of the hole cover pipe joint and the bolt locking, can prevent oil, water and gas. The leakage and the looseness of the bolt are directly related to the normal operation of the car.
The main varieties are:
(1) Anaerobic adhesive: It is characterized by simple coating process, fast curing speed and good sealing and sealing performance. According to different requirements, three methods of on-site coating, pre-coating and impregnation can be adopted. Among them, the pre-coating high-strength microcapsule type anaerobic adhesive is particularly suitable for the fast-paced requirements of mechanical coating of a large number of threaded connectors on automobiles. According to the estimated annual production volume of our company, the annual rubber consumption is close to 2t.
(2) Silicone sealant: It is unique for flat seals. It has good elasticity, oil resistance, heat resistance and aging resistance. It has simple coating process, strong strippability and easy disassembly. It can be used separately instead of gasket. The sealing effect is good.


Special process adhesives: A variety of adhesives are used in the automotive manufacturing process;
For example, the brake shoe glue for bonding the brake shoe and the friction plate is a modified phenolic resin-based adhesive, which has reliable bonding strength instead of riveting, can reduce noise and prolong the service life of the friction plate;
The filter element used in the production of the filter element is a PVC plastisol reinforced by a tackifying resin. The bonding strength is moderate and the processability is good, which can meet the operation requirements of the assembly line;
The infiltration agent for micro-hole plugging is effective in repairing the defects of the batt of powder metallurgy parts and engine blocks, cylinder heads, etc. The pressure-sensitive adhesive tape used in the assembly process of automobiles can protect the car itself from pollution and bumps. Retaining or assisting in positioning when assembling parts;
The synthetic resin adhesive for casting mainly includes three kinds of phenolic resin, furan resin and a small amount of modified urea-formaldehyde resin, and is widely used in the casting process of engine cylinders, cylinder heads and the like.

End summary
The automotive industry's demand for adhesives and sealants has developed over the past 20 years. Some automotive rubbers with relatively high technical difficulty have basically met the needs in major varieties. However, further work is needed to improve product quality and adapt to the production process of large-scale automotive production lines.