Adhesives&Sealants

### Adhesives

- **Definition**: A material capable of bonding two or more substrates together.

- **Classification**: Categorized by composition and performance into hot-melt, solvent-based, reactive, water-based, etc. Hot-melt adhesives melt when heated and cure upon cooling, widely used in paper products and packaging; solvent-based adhesives dissolve in solvents and cure as solvents evaporate, offering high bonding strength for wood, metals, and other materials; reactive adhesives cure through chemical reactions, delivering excellent mechanical strength (e.g., epoxy resins, polyurethane resins) for structural bonding applications; water-based adhesives use water as the solvent, featuring good environmental performance, suitable for bonding paper products and wood.

- **Performance Indicators**: Key metrics include bond strength, heat resistance, water resistance, and chemical resistance. Bond strength refers to the adhesive’s ability to hold substrates together; heat resistance denotes its capacity to maintain performance under high temperatures; water resistance and chemical resistance respectively refer to its ability to withstand humid environments and resist corrosion from chemical substances.

### Sealants

- **Definition**: A material used to seal the surfaces of objects, preventing the infiltration of liquids, gases, etc.

- **Classification**: Common types include silicone sealants, acrylate sealants, polyurethane sealants, epoxy sealants, etc. Silicone sealants offer excellent weatherability and aging resistance, widely applied in construction and automotive industries; water-based acrylate sealants are environmentally friendly and cost-effective, commonly used in construction and furniture manufacturing; polyurethane sealants exhibit high elasticity and oil resistance, extensively used in automotive and shipbuilding; epoxy sealants boast high strength and heat resistance, suitable for industrial manufacturing and aerospace fields.

- **Performance Characteristics**: Sealants can deform to match the shape of sealing surfaces, are non-sagging, and possess certain adhesive properties. They prevent the leakage of internal gases or liquids while blocking the intrusion of external dust and moisture.

### Application Fields

- **Construction**: Adhesives are used for splicing wood and panels; sealants seal gaps in doors, windows, and walls to enhance building airtightness and waterproofing.

- **Automotive Manufacturing**: Adhesives bond automotive body components; sealants seal engines, gearboxes, and other parts to prevent fluid leakage.

- **Electronics & Electrical Appliances**: Adhesives fix and bond electronic components; sealants seal electrical enclosures to prevent dust and moisture from affecting performance.

- **Aerospace**: Sealant-adhesives are used for sealing and bonding aerospace instrument assemblies, ensuring the tightness and reliability of equipment.