The functional requirements of adhesive joints are multifaceted, generally including mechanical strength, heat resistance, oil resistance, water resistance, electrical conductivity, and the ability to withstand environmental stress. The selected adhesive must also possess corresponding functions. The relevant adhesives are introduced below according to typical functional requirements.

1. Mechanical Strength
   Adhesives of this type should have good mechanical strength, including tensile strength, shear strength, and peel strength, etc. Epoxy resin adhesives are commonly used. However, their peel strength is relatively poor. If epoxy-nitrile rubber adhesives and phenolic-nitrile rubber adhesives are selected, satisfactory results can be obtained. In the repair of worn machine tool guides, an abrasion-resistant adhesive is required, and the AR-5 abrasion-resistant adhesive can be used. Its hardness reaches 11.8HB, which is composed of epoxy resin and inorganic fillers. For adhesives used for plastic carpets and beverage bottle labels, a relatively high shear strength and a relatively low peel strength are required.
2. Heat Resistance
   The long-term service temperature of general polymer adhesives is below 200°C. However, for some special applications of certain materials, a long-term service temperature above 200°C is required. For example, the adhesive used in microelectronic components needs to be bonded to a substrate at 400°C in an inert atmosphere; the structural adhesive used in supersonic aircraft is required to be used at 230°C for tens of thousands of hours; the adhesive used in missiles is required to maintain its mechanical properties at 540°C for more than 1 minute. These are all special-purpose adhesives for specific applications.
3. Oil Resistance
   For the bonding of oil pipeline joints and parts in lubricating oil, the adhesive is required to be bonded in an environment of oil stains and moisture without the possibility of surface treatment, and to obtain sufficient strength.
4. Water Resistance
   Generally, polar adhesives have strong hydrophilicity. In a humid environment, the strength of the joint will drop sharply.
5. Optical Properties
   In addition to having a certain bonding strength, the adhesive used for optical components must also meet the requirement of light transmittance, which is generally above 90%.
6. Other Functions
   The functional requirements of adhesive joints are diverse, such as electromagnetic, acoustic, and physiological effects and other functions.