The definition of bonding technology and the function of adhesives

1, the definition of bonding technology

Bonding technology is a method of firmly joining together the same or different materials by means of the adhesive force generated by the adhesive on the solid surface. There are two main forms of bonding: non-structural and structural. Non-structural bonding refers mainly to surface coating, sealing, and functional bonding. Typical non-structural adhesives include adhesives for surface bonding, seals, and conductive adhesives, etc., while structural bonding fixes structural units with adhesives. Bonding phenomenon together. The structural adhesives and their bonding points used must be able to transmit structural stresses and do not affect the structural integrity and suitability to the environment within the design range.

2, the function of the adhesive The main function of the adhesive is to connect the bonding material together. The stress transmission within the adhesive assembly is more uniform than that of the conventional mechanical fastening, and the bonded assembly structure is stronger and less costly than mechanical fastening (riveting, welding, interference joints, and bolting). ,light in mass. If the thin-walled piece adhesive is adhered to the thick-walled product, the full strength of the thin-walled piece can be fully utilized. The strength of mechanical fastening and welding structures is limited by fasteners or solder joints and their thermally sensitive areas.

Adhesive-bonded components have a smooth, flat appearance and do not exhibit a reduction in functional properties. This is particularly important for structural bonding. For example, the structural parts of Aerospace Industry have a smooth and smooth appearance, which helps to reduce the resistance and friction and reduce the frictional heating to a minimum. Therefore, the helicopter rotor blades were all assembled with adhesives. Adhesive bonding of tightly fitted electronic or electrical components also avoids bumps and benefits. The navigation appliance uses an adhesive assembly to obtain a flat, non-structural interference outer surface. Because the stress distribution in the adhesive joint is very uniform, the strength and rigidity of the bonded object can be fully embodied, and the quality can also be reduced. For example, the adhesive assembly of the spacecraft eliminates the negative load, increases the payload, improves the voyage, and saves freight. reduce.

Adhesives can be used for the bonding of various materials such as metals, plastics, rubber, ceramics, cork, glass, wood, paper, and fibers. When the joints of different materials are at a variable temperature, the adhesive can exert its unique use performance. The flexible glue can adjust the difference in the thermal expansion characteristics of the adherend and prevent the rigid rigid system from being damaged in the use environment. If the adhesive assembly is used at a relatively high temperature, the flexible adhesive can be suitably moved and migrated between different materials, and the difference in thermal expansion between different materials can be effectively adjusted through the movement or migration process to achieve the purpose of firm bonding and integration. Therefore, windows and metal frames, such as automobiles and airplanes, are usually bonded with adhesives.

The seal is actually a continuous bond. This bonding method can easily seal the adhesive joint. Prevent the intrusion of destructive liquids and gases. Adhesives can also be used instead of solid or foam gaskets for the sealing of gearbox housings, valve housings, automotive parts and other industrial components. Because the adhesive is mostly used in a liquid state, it can also be used as a potting sealant, such as circuit board, motor, electrical and electronic components commonly used sealing encapsulants.

Cracking or cracking of products or parts is a common phenomenon. The conventional repair method is to use welding. However, welding often results in thermal deformation stress of the repaired item. Especially for thin-walled parts, this welding method is not suitable. If the material is difficult to weld (such as Chin alloy) or in the explosion-prone occasions (such as oil tanks, downhole equipment, etc.) is more difficult to use welding repair, can only use a safe and reliable adhesive bonding method.

Casting defects (swells, plugging holes) have always been a problem in the foundry industry, and the common methods for repairing these defective parts require that skilled workers consume a large amount of material and time (Hi can be repaired, otherwise it becomes a waste product. Use special glue to fill Repairs save money and save money Parts wear and oversize or scratches account for more than 70 failures of mechanical parts. The traditional methods are surfacing, thermal spraying, electroplating, brushing, etc. Welding or thermal spraying It will cause the surface temperature of the parts to reach a high temperature, causing the parts to deform or form a micro crack, affecting the dimensional accuracy and normal use of the parts, while the electroplating and brush plating do not have thermal effects, but the coating thickness is strict and the application is limited. , And the use of adhesive surface sticky coating repair method is simple and easy, neither thermal effects nor the thickness of the coating, and can guarantee the wear resistance of the parts.

The phenomenon of “dropping, bleeding, and seepage” is a common situation in the industrial sector, especially in the chemical industry. The use of adhesive surface stick coating method is very safe and convenient sealing, saving time and effort, quality, and sometimes without affecting the production of the normal pressure at room temperature repair leaks to achieve the purpose of resealing, especially oil, chemical, pharmaceutical, rubber The maintenance of equipment in flammable and explosive occasions such as food and other industries, and the non-stopping of pressure and plugging have shown their unique advantages.

Source: 21st Century Fine Chemicals Network