CLASSIFICATION OF ADHESIVES

CLASSIFICATION OF ADHESIVES

1. A non-metallic substance applied to one or both surfaces of two separate items that binds them together and resists their separation.

   • Making a mind map on adhesives lets us research organize and visualize different concepts and their relationship in a clear way.
   • Related Disciplines
     • Chemistry
       • Ex. Origen of  adhesives, their chemical makeup an reactions , etc
     • Physics
       • Ex. Study of resistance, strength, tension, static, etc
     • Biology.
       • The study and design of bioadhesives, or naturally derived adhesives. How adhesives affect skin, health , etc. Etc
     • Design
       • Ex. Design and study of new materials like adhesives, new applications, design of product to be assembled, etc.
     • Mathematics
       • Ex. Calculation of precise ratios, doses, etc.

2. Categories

   • Solvent-based
     • Solvent(s) + Polymer + resin + additives
   • Water-born
     • Water + polymer + resin dispersion + wetting agent + thickener + preservative
   • 100% solids
     • Hot melt or reactive.
     • 1 or 2 polymer system

3. Origen

   • Natural
     • Vegetable starch (dextrin), natural resins, animal and hide-based glues, etc.
     • Pros:
       • Cost effective: Great tack and shear properties. Range of materials:
     • Cons
       • Weaker. Short life.
   • Synthetic
     • Thermoplastic
       • Thermoplastics are Polymers, which soften (become pliable and plastic) and melt when heated. Polyamides, cyanoacrylates, polyacrylates, polyvinyl acetate (PVA) are typical thermoplastic adhesives
     • Thermosets
       • Thermoset molecules are cross-linked by strong covalent intermolecular bonds, forming one giant molecule. Most of thermosetting adhesives are based onepoxies, polyesters, polyimides and phenolics.
     • Elastomer
       • Elastomersare polymers possessing high elasticity - may be reversibly stretched at high degree. Typical elastomeric adhesives are based on natural rubbers, silicones, acrylonitride butadiene (nitrile), neoprene, Butyl, polyurethane, styrene-butadiene.
     • Pros
       • Efficient Hypo-allergenic: Odourless: Flexibility:
     • Cons
       • Cost

4. MECHANISM

   • Mechanical Interlocking
   • Dispersion or Van der Waals force
   • Adsorption and Surface reaction
   • Electrostatic

5. Curing Method

   • One-part adhesives
     • Heat activated curing adhesives.
     • Light/UV activated curing adhesives (acrylics, cyanoacrylates, urethanes).
     • Moisture activated curing adhesives (RTV silicones, cyanoacrylates, urethanes).
     • Anaerobics
     • Pressure sensitive adhesives (PSA)

6. Mechanism