"introduction to epoxies" by hubert monteiro, royce international
DESCRIPTION
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.TRANSCRIPT
Dr. Hubert A. MonteiroTechnical Director
Royce International
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.
In what forms are Epoxies and Hardeners supplied?
LiquidsSolidsSolutionsSemi-formulated pastes
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.
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°FHeat cure: up to 360° F
Resins and Hardeners need to be handled with care in sensitive individuals to prevent dermatitis or rash.
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).
Epoxy Coatings
Epoxy Coatings
Solvent Free Solvent Containing
Water based
Liquid Solid Powder Coatings
AmbientCure
Water SolubleAnodicCathodicElectrodeposition
WaterDispersible
HeatCure
Coating Applications
• Civil Engineering• Construction• Flooring• Industrial Maintenance• Marine• Powder Coatings• Can/Coil/Packaging• Automotive
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.
Epoxy Mortars vs. Cement ConcreteMechanical Units Epoxy Mortar CementProperties (Filler: Binder=4.1) ConcreteCompressive Kg/cm² 800 – 1200 300-500Strength
Tensile kg/cm² 150-250 40-60Strength
Flexural kg/cm² 250-400 50-80Strength
Modulus of kg/cm² 1.6 x 10⁵30 x10⁵
Elasticity
Elongation % 0.1 0.02At Break
Coefficient of °C¯¹ 2.5x10⁵1.2x10¯⁵
Expansion
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.
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.
Advantages of CompositesHigh Strength to Weight Ratio
Material Strength toWeight Ratio
Aluminum 0.8Steel 1.0Titanium alloy 1.0Glass/ Epoxy 2.86Carbon/Epoxy 3.8Aramid (Kevlar)/Epoxy 5.09
Epoxies for ReinforcedPlastic Applications
• Filament winding• Pultrusion• Hand lay-up• Resin transfer moulding (RTM)• Vacuum bag/ pressure bag moulding• “Prepreg” processing Autoclave processing under pressure Flat laminates.
DDS Hardener for Aerospaceand Electronics Applications
4,4’DDS Normal grade for solution prepregs and
laminates.4,4’ DDS MicroMicropulverized grade for hot melt prepregs
and laminates.3,3’ DDSAerospace composite applications.
Epoxy Resins
Diglycidyl ether of Bisphenol A Diglycidyl ether of Bisphenol FEpoxy NovolacLong chain aliphatic diglycidyl ethersCycloaliphatic epoxy resinsMultifunctional resinsBrominated epoxy Resins
Epoxy Hardeners
Aliphatic amines/ adductsCycloaliphatic amines /adductsPolyaminoamides /AmidoaminesPhenalkaminesAromatic aminesFormulated anhydridesBF₃ and BCL ₃ adducts with amines
Choice of Hardener
ToxicityEase of mixing with the resinViscosityMixing proportion – Tolerance to variationsPotlifeConditions of applicationCure Time & Temperature
Factors related to Processing
Choice of Hardener
Factors related to cured system
Heat Deflection TemperaturePhysical, mechanical, electrical propertiesThermal stability (class of insulation)Chemical resistanceLight stabilityCost
AcceleratorsTertiary amines BDMA DMP-10 DMP-30
Imidazoles 1-methyl imidazole 2-methyl imidazole EMI-24 Phenols Phenol Nonyl phenol Cardanol Salicylic acid