Adhesive objects are metal, rubber, plastics, wood, fabric, leather and so on. Ceramic, glass, cement bonding can be between similar materials, can also be carried out between heterogeneous materials, and because of heterogeneous material performance is inconsistent, so in the selection of adhesives to take into account the characteristics of both to get better bonding quality.
Adhesives in use, in addition to the purpose of bonding, but also to fill, potting and coating the role. Generally speaking, high viscosity containing a large number of fillers in the adhesive after curing has a certain thickness. Resin Adhesive Gloss is good, and easy to film, so it is advisable to make protective coating layer. And some adhesives, by the curing mechanism to determine the viscosity of the surface clearance to small, then this adhesive can only play a role in bonding. The use of requirements generally refers to the adhesion of the position of the force mode, temperature, resistance to media and other working conditions.
The force of the adhesive site:
If the bonding site to ensure high strength requirements, should consider the use of thermosetting resin structural adhesives, such resins have a general adhesive can not form three-dimensional crosslinking structure, epoxy gum and phenolic resin are commonly used structural adhesives. Changes in their flexibility, in the matching process can be adjusted, epoxy-polyamine, epoxy-polyurethane, epoxy-polysulfide rubber, epoxy-polysulfide rubber, the best flexibility for phenolic-epoxy, phenolic-NBR, the latter is better flexibility. For the structure of some stress parts, thermoplastic polymer adhesives and synthetic rubber adhesives can be selected, thermoplastic polymer adhesive tensile and shear strength, and the resistance to peeling, tearing strength is poor, this is due to the poor strain capacity of such resins, and rubber adhesives flexible, adhesive pressure with the activity of the adhesive site deformation, Therefore, it has a good shear resistance, when the adhesive site by shearing and stretching force, the choice of this kind of adhesive is most appropriate. The adhesives commonly used in secondary stress structure are polyacrylate adhesives, poly methacrylate Adhesives, phenolic-chloroprene adhesives, phenolic-butyl adhesives, etc. Not withstanding the load, only used for bonding or as positioning, just ensure that the low strength of the structure of the adhesive is many, animal glue and plant gum can be used in wood, leather, fabric, paper and other bonding; phenolic resin adhesives, urea-formaldehyde resin adhesives, resorcinol formaldehyde resin adhesives, polyester resin adhesives, synthetic rubber adhesives, Poly Vinyl Acetate Adhesive, phenolic-polyvinyl acetal adhesive can be selected.
The temperature resistance of various adhesives are very different, in the need to select adhesives, we must pay attention to the adhesion of the site to withstand the heat-resistant aging, hot and cold cycling, high and low temperature and other conditions.
Dielectric resistance and other working conditions:
Some bonding is not required to water, alkali or acidic substances, and some to work outdoors, weather the sun, rain and the role of the atmosphere, and some require high insulation performance. The use of adhesives in electronic products requires reliable electrical properties, silicone adhesives in the electronics industry is commonly used as metal and non-metallic sealing, the rubber layer has excellent electrical insulation.
To obtain the ideal bonding effect, in addition to the selection of appropriate adhesives, the most appropriate bonding process and operation methods must be adopted. There are many ways to adhere to the operation, there are brush coating, spraying, but also injection of plastic liquid. According to the structure, the thickness of the glue, the speed of the initial viscosity, fluidity and so on, choose the appropriate coating method.
In the premise of satisfying the requirements, we should try to choose cheap and more versatile adhesives, such as epoxy resin adhesives, neoprene adhesives, polyurethane adhesives and so on.