phenolic resins 2

1. Phenolic Resins
CHEMICAL TECHNOLOGY
PROJECT
THUMATI VAMSI MADHAV – B130912CH
UDIT SINGHAL – B130575CH
T.NEELAVENI – B130726CH
SUBMITTED BY :

2. Phenolic Resins

3. INDEX
•HISTORY
•ABOUT
•PROPERTIES
•TYPES OF RESINS
•APPLICATIONS
•ENGINEERING PROBLEMS
•SUGGESTIONS

4. HISTORY
•The First phenolic resins were produced by poly
condensation of phenol with aldehyde in 1860.
•In 1860 ‘VON BAYER’ First reported the
reaction between phenol and aldehyde
•The phenol resin condensation was used
industrially in 1902 by ‘BLUMMER’ for
production of novalacs.

5. What is phenolic resin?
•Phenolic resins are polycondensation products of phenols and
aldehydes , in particular phenol and formaldehyde .
•Phenolic resin is a heat-cured plastic formed from a reaction of
a carbon-based alcohol and a chemical called aldehyde.
•Formaldehyde is a common raw material for this type of resin ,
but others related chemicals can be used. The resin is hard,
heat resistant, and can be mixed with a wide range of materials
for industrial and residential uses.
•Old phones were made of Bakelite , phenolic resin .

6. PHENOL-FORMALDEHYDE
REACTIONS: CONDENSATIONS AND POLYMERIZATIONS

7. Phenyl formaldehyde resins
• The reaction of phenol or substituted phenol with an
aldehyde, in the presence of an acidic or basic catalyst
is used to prepare phenol formaldehyde resins.
• Uses: Phenolic resins are used in adhesives, coatings,
and molding compounds.
• Heat of reaction: -180 cal/g
OH OH
(CH2OH)n1
(CH2OH)n2
+ (n1+n2) HCHO
NaOH

8. One step resin :
 In these , all the necessary reactants (phenols, formaldehyde and
catalyst) required to produce a thermosetting resin are charged into
resin kettle in the proper proportions and react together .
 An alkaline catalyst is used.
 The resin, as charged from the kettle, is thermosetting or heat-
reactive and rquires only further heating to complete the reaction to
an infusible, insoluble state
Two step resins :
• Only part of the necessary formaldehyde is added in the kettle in
making these resins, and an acid catalyst is used.
•They are permanently fusible or thermoplastic when discharged
from the kettle but react with additional formaldehyde to produce a
thermosetting resin

9. Flow chart:

10. Why Phenolic Resin?
Superior Creep Resistance
Strength and stability under load
Low weight high strength and modulus
Strength and rigidity
Chemically Resistant
Harsh marine environment
Excellent flammability resistance and low smoke and toxicity
Increased level of safety
High carbon and char yield
Retains level of strength and integrity should fire break out

11. Phenolic’s high modulus and excellent heat and creep resistance resists
fracture under pressure as proven in industry “Conductivity test”
Why Phenolic Resin?

12. Phenolic resins are yellow to brown in colour and the coloration can be very
intense. Pale phenolic resin become colored immeditately after production during
storage or processing. The coloration is less intense only int eh case of phenolic
resins from para-alky-substituted phenols
The Viscosity of phenolic resins or their solution is measure at hight
concentrations, e.g. in 30-80% solution.
Cross-linked phenolic resins are hard substances which only have a small fracture
strain and cannot be melted.
Phenolic resins can be plasticized. Their compatibility with plasticizers can be
adjusted by introduction of hydrophilic or hyrdrophobic groups.
Physical Properties

13. There are Two Types of Phenolic Resins
Novolac
Molar excess of phenol
Require an external curing agent
Usually
hexamethylenetetramine
Resol
Typically there is a molar excess of
formaldehyde
Do not require an external curing
agent
Single Stage
Six month shelf life

14. NOVOLAC
•Novolak resins are typically cured with 5–15% hexa as the cross-linking agent.
The reaction mechanism and reactive intermediates have been studied by
classical chemical techniques (3,4) and the results showed that as much as 75%
of nitrogen is chemically bound. More recent studies of resin cure (50–53)
have made use of TGA, DTA, GC, IR, and NMR . They confirm that the cure
begins with the formation of benzoxazine , progresses through a benzylamine
intermediate, and finally forms (hydroxy)diphenylmethanes (DPM).
•IN the formation of novolacs, substitution in condensation reactions occur
simultaneous. In large reaction vessels formaldehyde is metred to a phenol –
catalyst mixture and the rate of addition is controlled depending on the head
evolved for safety reasons. When using smaller vessels, even under laboratory
conditions, care must be take cbecause of exothermic reaction.

15. Used in :
Tackifiers for Rubber, as a varnish, Raw materials for Epoxy resins, Thermosets,
grinding wheels, printing technology, Positive offset printing plates.

16. Resol
The production of resols differs from that of novolacs in that the reactions
between phenol and formaldehyde are not allowed to go to completion but are
stopped at the stage where auto-cross-linking resols are still liquid or soluble.
The continuation of the condensation reactions beyond the resol stage leads
to resins which are no longer soluble but can only be swelled and which are
known as resitols.
The final cross-linking to from resitoles gives completely cross-linked plastics.
In resol production, the concentration for formaldehyde and the degree of
condensation must be controlled during the reaction.

17. Uses of Resol
● Interior of Vehicles.
● Construction Adhesives.
● Abrasives.
● Foamed Plastics
● Fiber Bonding
● Decorative Laminates
● Chipboard Adhesive
● Binding agents for molding sand.

18. Corrosive coatings for
Storage tanks, semi tank trailers, railroad tank cars, fans blowers, and fin tube coils
Other Applications
Binder for
Friction pads, brake pads, grinding wheels, plywood and particle board
Wear Resistance
Gas meter valves, pump seals, caster wheels
Dimensional Stability & Thermal Performance
Brake pistons, transmission parts, electrical motor brush cards
Electrical insulation
terminal strips, commutators, capacitor cans and caps

19. Engineering Problems
•All the raw materials and catalyst were charged to the reactor
at once followed by the addition of heat.
•Heat generated exceeded the cooling capacity of the system
•Excessive pressure generated by a runaway reaction.
•Pressure generated could not be vented through the
emergency relief system.
•Accumulation of Formaldehyde
•Deviation from process
•Poor agitation
•Improper heating or cooling

20. SUGGESTIONS
•Modify processes to improve inherent safety.
•Minimize the potential for human error.
•Understand events that may lead to an
overpressure and eventually to vessel rupture.
•Use lessons learned.
•Evaluate Standard Operating Practices.
•Evaluate employee training and oversight.
•Evaluate the effectiveness of the emergency
relief system.

21. Thank you