What are the advantages of using hot melt adhesive in the automotive industry?

The automotive industry is the second largest industry in China after the real estate industry, and also the largest industry in China. In a sense, the development level of the automotive industry represents the industrial level of a country. With the rapid development of China's automobile industry and the improvement of Chinese people's living standards, the Chinese automobile market is thriving, forming a strong competitive market with sufficient supply. So, while people pay attention to car safety and driving experience, they also pay more attention to the indoor air quality of cars, cannot tolerate irritating odors, and attach greater importance to the quality of life.

With the requirements of environmental protection and consumer demand for air quality inside cars, coupled with the fast curing characteristics of hot melt adhesive, it is widely used as an environmentally friendly hot melt adhesive in the bonding of car roofs, car door panels, car carpets, car wiring harnesses, tire protection, car labels, car filters, car lights, dashboard and other components in car manufacturing.

Hot melt adhesive has fast solidification and is suitable for automated high-speed assembly line operations; Hot melt adhesive materials are widely used, and automobiles are mainly composed of a large number of metal and non-metal parts, which is suitable for the bonding between these metal materials and non-metal materials, and between non-metal materials; Hot melt adhesive is easy to apply, with no solvent evaporation and no need for drying equipment. It can be applied in various ways, such as spraying, roller coating, scraping, or composite with hot melt adhesive film, mesh, powder, etc. It can be automatically bonded or manually bonded; Hot melt adhesive is 100% solid content, easy to store, energy-saving, environmentally friendly, non-toxic, low odor, low VOC, and meets the requirements of automotive interior environment, etc.

The common hot melt adhesives in the market mainly include EVA hot melt adhesive, PA hot melt adhesive, PE polyester hot melt adhesive, PO hot melt adhesive, SEC hot melt pressure-sensitive adhesive, TPU hot melt adhesive, and PUR hot melt adhesive. Hot melt adhesives of different main materials have their own characteristics and advantages and disadvantages. For example, EVA hot melt adhesive, which is the most widely used, has obvious limitations in high temperature resistance. For example, PUR hot melt adhesive, which has the strongest adhesive strength, is not a thermoplastic material, cannot be reused, and has a high cost, requiring high priced adhesive equipment to match.

The content and methods that need to be tested for different applications of adhesive types often take into account the actual production process and application environment of the customer for corresponding laboratory simulation evaluation tests. Specific tests include: the machine performance of the adhesive (the customer's coating process and the heat stability of the adhesive), the bonding test of the customer's substrate, the high and low temperature resistance of the test sample, the accelerated aging performance of the test sample (service life), etc.

Taking car lights as an example, the main sealing methods for car lights are hot melt adhesive, silicone sealant, polyurethane and foam materials with mechanical fixation, among which hot melt adhesive has the largest market usage. Each sealing method has its advantages and disadvantages. After years of research and investigation by our company, qualified hot melt adhesive and mechanical fixation every 10-15 centimeters are reliable and efficient solutions for sealing car lights.

Hot melt adhesive undergoes only physical processes and no chemical reactions throughout its entire usage. The process is simple, reliable, the effect is controllable, and predictable. Silicone and PUR require a chemical reaction, which is complex and difficult to control. Often, due to incomplete reactions, there are unreacted components that can never cure, resulting in fogging and even no strength. And this result is actually difficult to avoid, because objectively it is difficult to fully mix the two components A and B in exactly the right proportion. Therefore, the effectiveness of silicone and PUR in practical use can never reach the theoretical effect or even the laboratory effect. The advantages of hot melt adhesive are more obvious in terms of convenience, cost, efficiency, safety, hygiene, and other aspects.