The application environment and performance requirements of headlight adhesive
With the microfabrication of the internal structure of the lamp, the high performance of the headlight adhesive becomes more important. The application requirements and bonding mechanism of headlight adhesive are briefly described, so let's learn the development status of headlight adhesive together below!
China's headlight adhesive industry began in the mid-1950s, developed rapidly in the 1980s with the introduction of technology, and entered a new stage of development after the 1990s. The popularity of domestic private cars has injected new vitality into the automotive adhesive industry, further increasing the use of adhesives. Headlight adhesive has a variety of performance advantages, can achieve to improve the structural strength of the bonding device, rust and corrosion prevention, heat insulation and shock absorption, sealing and other effects, and simplify the construction process, replacing part of the traditional bonding technology such as welding and riveting, with a certain beautification effect. Among them, lamp adhesive (referred to as lamp adhesive) as an important part of automotive adhesives, has received wide attention from the industry.
Lamp adhesive bonding mechanism and its application in the light
Since the 1940s, various theories including adsorption theory, diffusion theory, electrostatic theory, mechanical interlocking theory and chemical bonding theory have been proposed to explain the bonding behavior.
1)Adsorption theory: When the adhesive wets the bonded material, intermolecular forces (including hydrogen bonding and van der Waals forces, etc.) are generated between the molecules of the interface adhesive and the bonded material, and the adhesive is firmly bonded to the bonded material.
2) diffusion theory: the adhesive and the bonded material diffusion, the formation of two molecular composition of the mixed interface layer to achieve bonding. The theory is mainly applicable to the adhesive and the adhesive are polymer cases, especially for the two polymer compatibility and molecular chain movement ability of the case.
3) electrostatic theory: the formation of a double layer between the adhesive and the bonded material, electrostatic force to prevent the adhesive and the bonded material separation, so that the material bonding. Adhesive stripping process of the bonded material discharge phenomenon confirms the existence of the theory.
4) mechanical interlocking theory: the surface of the bonded material is not completely smooth, the surface of which there are grooves and gaps of different depths, liquid adhesive can penetrate it, and after curing and molding is anchor-like or hook-like mutual cooperation, bonding materials. Mechanical interlocking is the main bonding mechanism of surface rough materials, especially porous materials.
5) Chemical bonding theory: adhesive molecules and the molecules of the bonded material generate chemical bonds to provide adhesion. Chemical bonding force is usually greater than the intermolecular force, and its density reaches a certain level, it can significantly improve the bonding strength.
Light rubber according to the above mechanism, in the bonding suitable for the main chain structure of the light ware adhesive, such as polar materials, use the main chain has a polar group of light ware adhesive; add a suitable coupling agent in the adhesive; improve the surface roughness of the light bonding part to remove the light bonding surface weak boundary layer (such as the natural oxide layer on the surface of aluminum); use a suitable primer for non-polar materials, surface plasma treatment or combustion treatment . 2 Light rubber application environment and performance requirements
The performance of light rubber is mainly expressed in the use of process performance and adhesive performance. Compared with ordinary adhesives, light rubber use environment is special, in addition to mechanical properties, anti-aging properties and other requirements, should also have the following properties.
1) High and low temperature resistance: In the non-use state, the light temperature can reach 0 below, especially in the northern region of China, the winter temperature is generally lower than -30 (can be reduced to -50 ); after a long time use, the temperature of the light will reach 170 above. Therefore, the light rubber in different temperatures for long-term use, must ensure that the low-temperature flexibility and high temperature is not damaged.
2) Anti-vibration and anti-fatigue performance: vibration will inevitably occur during the driving of the vehicle, especially when the driving surface is uneven, the amplitude and frequency will become high. Light rubber is prone to cumulative damage caused by long-term vibration, and serious problems such as broken lights and water leakage. Therefore, the light rubber must have good anti-shock and anti-fatigue properties to ensure the stability and safety of light use.
3) Low fogging value: fogging value is used to indicate the amount of volatile components condensed on the inner surface of the lamp. Light as a vehicle lighting and signal indication factors, the vehicle's driving safety is particularly important, light fuzzy will certainly reduce the safety of the driving process, but also reduce the life of the vehicle, damage to the aesthetic. At present, reduce the light fogging value has become one of the important issues of the lighting industry. The fogging needs three conditions, respectively, condensation core, sufficient water vapor, below the temperature region of moisture condensation temperature. The main effect of light glue on fogging is the heat volatile components that can form the condensation core. Therefore, in order to improve the performance and appearance of the lamp, the heat volatile component of the light adhesive must be low.
The above introduction is the development status of the lamp adhesive, for more information, please feel free to contact us!