Hubert presents an introduction to epoxies. Hubert Monteiro is a Technical Consultant for Royce International and, as an active member of the Thermoset Resin Formulators Association (TRFA) since it was founded 10 years ago, has a unique perspective on the role industry associations play in the technical community.

1. Dr. Hubert A. Monteiro
Technical Director
Royce International

2. What are Epoxy resins?
A family of thermosetting resins which have the
following chemical group:
When reacted with a hardener(or curing agent), they
set to a hard mass which does not melt or dissolve in
solvents.
Hardeners are typically amine or anhydride based
chemistry.

3. In what forms are Epoxies and Hardeners
supplied?
Liquids
Solids
Solutions
Semi-formulated pastes

4. What are the advantages of Epoxies?
• Bonds strongly to most materials including metals,
concrete, glass, ceramics, stone, wood, leather.
Exceptions are plastics materials like polyethylene,
polypropylene, Teflon, etc.
• Excellent resistance to chemicals and solvents.
• Very good electrical insulating properties.
• Outstanding mechanical strength including tensile,
compressive, flexural and modulus.
• Very little shrinkage on curing, thus providing good
dimensional stability.

5. What are the limitations of Epoxies?
Limited pot life when resin and hardener are
mixed.
Cured systems have poor resistance to U.V. Thus,
outdoor exposure over time tends to yellow and
chalk coatings and electrical insulators can begin
to “track”.
Limited temperature resistance:
Ambient cure: 150-250°F
Heat cure: up to 360° F
Resins and Hardeners need to be handled with
care in sensitive individuals to prevent dermatitis
or rash.

6. Industries in which Epoxies are utilized
• Coatings, Paints and Lacquers.
• Civil Engineering and Construction.
• Aerospace and Industrial Composite.
• Electrical & Electronics (i.e. casting, impregnation,
insulation, laminates, potting, etc).
• Adhesives and Sealants.
• Recreational and Sporting Equipment (i.e. golf shafts,
skies, snowboards, tennis racquets).
• Foundries and tooling (i.e. automotive).

7. Epoxy Coatings
Epoxy
Coatings
Solvent Free Solvent Containing Water based
Liquid Solid Ambient Heat Water Soluble Water
Powder Cure Cure Anodic Dispersible
Coatings Cathodic
Electrodepositio
n

8. Coating Applications
• Civil Engineering
• Construction
• Flooring
• Industrial Maintenance
• Marine
• Powder Coatings
• Can/Coil/Packaging
• Automotive

9. Epoxies for Civil Engineering and
Construction Applications
Coatings
 Solvent-free lining of concrete and steel tanks,
 Water-based coatings for concrete.
 Powder coatings for rebars.
Mortars
 Self-leveling and trowellable floors
 Pothole repair for roads and airfields.
 Grouting of heavy machinery.
Bonding
 Bonding of prefabricated elements in bridges and other structures.
 Bonding new to old concrete.
 Bonding external reinforcement to concrete.
Injection Systems
 Grouting and repair of concrete cracks.

10. Epoxy Mortars vs. Cement Concrete
Mechanical Units Epoxy Mortar Cement
Properties (Filler: Binder=4.1) Concrete
Compressive Kg/cm² 800 – 1200 300-500
Strength
Tensile kg/cm² 150-250 40-60
Strength
Flexural kg/cm² 250-400 50-80
Strength
Modulus of kg/cm² 1.6 x 10⁵ 30 x10⁵
Elasticity
Elongation % 0.1 0.02
At Break
Coefficient of °C¯¹ 2.5x10⁵ 1.2x10¯⁵
Expansion

11. Epoxies for Electrical Applications
• Ambient cure potting, casting and encapsulation of small
low voltage components.
• Battery sealing compounds.
• Joints and termination in electrical cables and gas seals in
telecommunication cables.
• High voltage insulators and bushings.
• Switch gear parts in circuit breakers.
• Current and potential measuring transformers.
• Impregnation of large rotating machines (VPI process).
• Resin-rich mica-paper tapes and resin-poor tapes for
insulation of coils in large rotating machines.

12. Epoxies for Electronic Applications
• Transfer molding compounds for encapsulating of
semiconductors.
• Liquid casting resins for potting active and passive
components.
• Brominated resins for base laminates for printed wiring
boards.
• Conductive solders for mounting heat sensitive
components.
• Dip-coating and conformal coatings for components and
assemblies.

13. Advantages of Composites
High Strength to Weight Ratio
Material Strength to
Weight Ratio
Aluminum 0.8
Steel 1.0
Titanium alloy 1.0
Glass/ Epoxy 2.86
Carbon/Epoxy 3.8
Aramid (Kevlar)/Epoxy 5.09

14. Epoxies for Reinforced
Plastic Applications
• Filament winding
• Pultrusion
• Hand lay-up
• Resin transfer moulding (RTM)
• Vacuum bag/ pressure bag moulding
• “Prepreg” processing
Autoclave processing under pressure
Flat laminates.

15. DDS Hardener for Aerospace
and Electronics Applications
4,4’DDS
Normal grade for solution prepregs and laminates.
4,4’ DDS Micro
Micropulverized grade for hot melt prepregs and
laminates.
3,3’ DDS
Aerospace composite applications.

19. Epoxy Resins
Diglycidyl ether of Bisphenol A
Diglycidyl ether of Bisphenol F
Epoxy Novolac
Long chain aliphatic diglycidyl ethers
Cycloaliphatic epoxy resins
Multifunctional resins
Brominated epoxy Resins

20. Epoxy Hardeners
Aliphatic amines/ adducts
Cycloaliphatic amines /adducts
Polyaminoamides /Amidoamines
Phenalkamines
Aromatic amines
Formulated anhydrides
BF₃ and BCL ₃ adducts with amines

21. Choice of Hardener
Factors related to Processing
Toxicity
Ease of mixing with the resin
Viscosity
Mixing proportion – Tolerance to variations
Potlife
Conditions of application
Cure Time & Temperature

22. Choice of Hardener
Factors related to cured system
 Heat Deflection Temperature
Physical, mechanical, electrical properties
Thermal stability (class of insulation)
Chemical resistance
Light stability
Cost

23. Accelerators
Tertiary amines
 BDMA
 DMP-10
 DMP-30
Imidazoles
 1-methyl imidazole
 2-methyl imidazole
 EMI-24
Phenols
 Phenol
 Nonyl phenol
 Cardanol
 Salicylic acid