Adhesives, Glue and Sealants

Adhesives, glues, and sealants are substances used to bond two surfaces together (adhesives/glues) or to create a barrier against the passage of fluids or gases (sealants). While often used interchangeably, sealants typically have lower strength but higher flexibility than adhesives.

Types of Adhesive, Glue and Sealants

Adhesives/Glues:

Natural: 

Animal glue, starch glue.

Synthetic:

Reactive: Epoxies, Polyurethanes, Cyanoacrylates (Super Glue), Silicones, Acrylics.

Non-Reactive: Hot melt adhesives, Pressure Sensitive Adhesives (PSAs), Solvent-based adhesives, Water-based adhesives (PVA, EVA).

Sealants: 

Silicones, Polyurethanes, Acrylics, Butyl, Polysulfides.

Applications in Various Industries:

Construction: Bonding building materials (wood, concrete, metal), sealing joints, weatherproofing.

Automotive: Bonding body panels, interior components, sealing windows and engines.

Electronics: Encapsulation, bonding components, thermal management.

Packaging: Sealing boxes, laminating films.

Aerospace: Bonding lightweight structures, sealing fuel tanks.

Healthcare: Medical devices, wound dressings.

Consumer Goods: Footwear, furniture, DIY repairs.

Material Selection Considerations:

• Substrate Compatibility: Must adhere well to the materials being joined (e.g., metal to metal, plastic to plastic, dissimilar materials).
• Required Bond Strength: Shear, tensile, peel strength (e.g., high strength for structural bonding, lower for temporary).
• Environmental Resistance: Temperature range, moisture, UV radiation, chemicals.
• Flexibility/Rigidity: Depending on whether movement is expected (sealants are more flexible).
• Cure Time and Method: Fast-curing for assembly lines, slower for repositioning.
• Viscosity: For dispensing and spreading.
• Safety and Regulations: Toxicity, VOC emissions.