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Phenolic Resin reacts with formaldehyde at the ortho and para sites (sites 2, 4 and 6) allowing up to 3 units of formaldehyde to attach to the ring.
Phenolic resins are a type of synthetic thermosetting resin invented by Dr. Leo Baekeland in 1907. The material was originally called Bakelite.
Phenolic Resins, as a group, are formed by a step-growth polymerization reaction that can be either acid- or base-catalysed.
CAS Number: 9003-35-4
Molecular Formula: (C6H6O.CH2O)x
Molecular Weight: 124.14
EINECS Number: 500-005-2
Synonyms:Phenol-formaldehyde resin, 9003-35-4, ormaldehyde-phenol copolymer, phenol,polymerwithformaldehyde, phenol-formaldehyde, Phenolic resin,dimethylbenzene modified, Phenolic moulding plastics PF2A2-131, Phenolic granular injection moulding plastic SP2501J, Phenolic resin,melamine modified, Phenolic resin 264, Phenolic resin,thermoset
Phenolic Resin, also called phenolic resins or phenoplasts, are synthetic polymers obtained by the reaction of phenol or substituted phenol with formaldehyde.
Phenolic Resin is used as the basis for Bakelite, PFs were the first commercial synthetic resins.
They have been widely used for the production of molded products including billiard balls, laboratory countertops, and as coatings and adhesives.
They were at one time the primary material used for the production of circuit boards but have been largely replaced with epoxy resins and fiberglass cloth, as with fire-resistant FR-4 circuit board materials.
There are two main production methods.
One reacts phenol and formaldehyde directly to produce a thermosetting network polymer, while the other restricts the formaldehyde to produce a prepolymer known as novolac which can be moulded and then cured with the addition of more formaldehyde and heat.
There are many variations in both production and input materials that are used to produce a wide variety of resins for special purposes.
Phenolic Resin is a type of synthetic polymer that is formed through the reaction of phenol (an aromatic alcohol) with formaldehyde under controlled heat and pressure conditions. Phenolic Resin belongs to one of the oldest families of synthetic resins, first developed in the early 20th century, and is still widely used today because of its excellent mechanical strength, high thermal stability, and good resistance to chemicals, water, and wear.
Unlike many other plastics, phenolic resins are thermosetting materials, meaning that once they are cured or hardened, they cannot be softened again by heating, which makes them particularly suitable for applications that require durability and resistance to extreme conditions.
Phenolic Resins are often used as adhesives, binders, and coatings in industries such as automotive, aerospace, construction, and electronics, where they provide strength, insulation, and protective surfaces.
For example, they are found in brake pads, electrical components, circuit boards, wood laminates, and molded parts that must withstand heat and stress.
Their ability to bond strongly to other materials, combined with their flame resistance and insulating properties, also makes them valuable in safety-critical and high-performance environments.
Phenolic Resins are a group of the most versatile polymers yet invented.
Although they came into existence at the very start of the age of polymers, they continued to be developed into more and more applications.
Since formaldehyde exists predominantly in solution as a dynamic equilibrium of methylene glycol oligomers, the concentration of the reactive form of formaldehyde depends on temperature and pH.
This was effectively the first plastic to be sold commercially, and was typified by the old-style black telephones.
The initial reaction in all cases involves the formation of a hydroxymethyl phenol: HOC6H5 + CH2O → HOC6H4CH2OH
The hydroxymethyl group is capable of reacting with either another free ortho or para site, or with another hydroxymethyl group.
The first reaction gives a methylene bridge, and the second forms an ether bridge: HOC6H4CH2OH + HOC6H5 → (HOC6H4)2CH2 + H2O
2 HOC6H4CH2OH → (HOC6H4CH2)2O + H2O
The diphenol (HOC6H4)2CH2 (sometimes called a "dimer") is called bisphenol F, which is an important monomer in the production of epoxy resins.
Bisphenol-F can further link generating tri- and tetra-and higher phenol oligomers.
Phenolic Resins are in two types as resorcinol and novalac resins.
Phenolic Resin manufactured at Polisan Kimya facilities is resol type.
Phenolic Resins are produced through polycondensation of phenol, formaldehyde and urea in alcali environment.
Condensation is realized in three stages.
Firstly, Phenolic Resins are produced with the introduction of phenol and formaldehyde and condensation is realized through formation of ether bridges with separation of water from methylol phenols and ethylene bridges with separation of water and formaldehyde.
Phenolic Resins are preferential products since they feature good thermal and chemical resistance, good dimensional stability and molding at low cost when they are molded under temperature and pressure.
They have high thermal and humidity resistance, therefore, used particularly in outdoor applications or areas where water is present.
Phenol-formaldehyde resins have an extensive area of use.
They are used as insulation material particularly in marine plywood production, construction molds, OSB production, glasswool and rockwool production, compact lamination and decorative lamination production, postforming applications, kraft paper impregnation, casting industry, refractory brick production, foam production and underground resources.
Phenolic Resin, also called phenolic resins or phenoplasts, are synthetic polymers obtained by the reaction of phenol or substituted phenol with formaldehyde. Used as the basis for Bakelite, PFs were the first commercial synthetic resins.
They have been widely used for the production of molded products including billiard balls, laboratory countertops, and as coatings and adhesives.
They were at one time the primary material used for the production of circuit boards but have been largely replaced with epoxy resins and fiberglass cloth, as with fire-resistant FR-4 circuit board materials.
There are two main production methods.
One reacts phenol and formaldehyde directly to produce a thermosetting network polymer, while the other restricts the formaldehyde to produce a prepolymer known as novolac which can be moulded and then cured with the addition of more formaldehyde and heat.
There are many variations in both production and input materials that are used to produce a wide variety of resins for special purposes.
Phenolic Resins are divided into two different types, novolacs and resoles.
Both have high temperature stability up to 300° – 350° C, high water and chemical stability.
Phenolic Resins are often dark-colored from yellow to dark red, and have an excellent price/performance profile.
Phenolic resin is notable for being a type of thermoset polymer, meaning that it cures into an altered form than when it is uncured, however, unlike other varieties of plastic polymers, it cannot be re-melted and re-molded.
This comes with the cost of recyclability, as the resin cannot be re-molded after it is cured and taken shape.
Other polymer resins include polyester, urethane, epoxy, and melamine, but let’s look at the properties and uses of phenolic resin to convince you why phenolic resin is the right thermoset for your business.
Melting point: 94 °C
Boiling point: 229.3 °C [at 101,325 Pa]
Density: 1.10 g/cm³
Vapor pressure: 3.18 Pa at 25 °C
Storage temperature: Sealed in dry, room temperature
Form: Granule
Color: Light yellow
Water solubility: 1.557 mg/L at 25 °C
Dielectric constant: 4.5 (ambient)
Stability: Stable. Incompatible with strong oxidizing agents
InChI: InChI=1S/C6H6O.CH2O/c7-6-4-2-1-3-5-6,1-2/h1-5,7H,1H2
InChIKey: SLGWESQGEUXWJQ-UHFFFAOYSA-N
SMILES: OC1C=CC=CC=1.C=O
LogP: 3.564 at 25 °C
Phenolic Resin is prepared as follows: C6H5OH+H2C=O ---> [-C6H2(OH)CH2-]n
The ratio of formaldehyde to phenol is high enough to allow the thermosetting process to take place without the addition of other sources of cross-links.
The ratio of formaldehyde to phenol is low enough to prevent the thermosetting reaction from occurring during manufacture of the resin.
At this point the Phenolic Resin is termed novolac resin.
Subsequently, hexamethylenetetramine is incorporated into the material to act as a source of chemical cross-links during the molding operation (and conversion to the thermoset or cured state).
Phenolic Resins are phenol-formaldehyde resins with a formaldehyde to phenol molar ratio of less than one.
In place of phenol itself, they are often produced from cresols (methylphenols).
The polymerization is brought to completion using acid-catalysis such as sulfuric acid, oxalic acid, hydrochloric acid and rarely, sulfonic acids.
The phenolic units are mainly linked by methylene and/or ether groups.
The molecular weights are in the low thousands, corresponding to about 10–20 phenol units.
Obtained polymer is thermoplastic and require a curing agent or hardener to form a thermoset.
Phenolic Resin is a hardener added to crosslink novolac.
At a temperature greater than 90 °C, it forms methylene and dimethylene amino bridges.
Resoles can also be used as a curing agent (hardener) for novolac resins.
In either case, the curing agent is a source of formaldehyde which provides bridges between novolac chains, eventually completely crosslinking the system.
Novolacs have multiple uses as tire tackifier, high temperature resin, binder for carbon bonded refractories, carbon brakes, photoresists and as a curing agent for epoxy resins.
Phenolic Resin can be produced in different forms, such as liquid resins for coatings or powdered resins for molding and laminating processes, allowing manufacturers to tailor them for specific industrial uses.
However, because they are made from phenol and formaldehyde, their production and processing require careful handling to avoid exposure to potentially harmful chemicals, which has led to the development of improved formulations and safer alternatives in recent years.
Phenolic resin is a man-made polymeric material that results from the chemical reaction between phenol, which is a hydroxy-substituted aromatic compound, and formaldehyde, which is a simple aldehyde, under controlled conditions of temperature, pressure, and catalyst.
This reaction leads to the formation of a rigid three-dimensional network structure, which gives phenolic resins their thermosetting nature.
Once they are cured through heat or catalysts, they become permanently hard and do not soften or melt upon reheating, which makes them fundamentally different from thermoplastic materials.
Because of this irreversible curing behavior, phenolic resins are highly valued in applications where dimensional stability, mechanical strength, and resistance to environmental stress are crucial.
In terms of performance, phenolic resins are known for their excellent heat resistance, meaning they can maintain their mechanical and structural integrity even under high-temperature conditions, which is why they are commonly used in components such as brake linings, clutch facings, and other friction materials in the automotive and aerospace sectors.
They also have outstanding electrical insulation properties, which has made them one of the most widely used resins in the manufacture of circuit boards, electrical switches, and insulating components.
Another important property is their high resistance to chemicals, solvents, and moisture, which ensures their long-term durability in harsh industrial and environmental settings.
Uses Of Phenolic Resin:
Phenolic Resin is used in binders, adhesives, laminates, impregnation products, surface coatings, casting sand, etc.
Phenolic Resin is a synthetic resin, commonly known as phenolic, made by the reaction of phenol and formaldehyde, and employed as a molding material for the making of mechanical and electrical parts.
The resins are also used for laminating, coatings, and casting resins.
Phenolic resins are used most extensively as thermosetting plastic materials, as there are only a few uses as thermoplastics.
The polymer is composed of carbon, hydrogen, oxygen, and sometimes nitrogen.
Its molecular weight varies from a very low value during its early state of formation to almost infinity in its final state of cure.
The chemical configuration, in the thermoset state, is usually represented by a three-dimensional network in which the phenolic nuclei are linked by methylene groups.
The completely cross-linked network requires three methylene groups to two phenolic groups.
A lesser degree of cross-linking is attainable either by varying the proportions of the ingredients or by blocking some of the reactive positions of the phenolic nucleus by other groups, such as methyl, butyl, etc.
Reactivity can be enhanced by increasing the hydroxyl groups on the phenolic nuclei, for example, by the use of resorcinol.
The outstanding characteristics of phenolics are good electrical properties, very rigid set, good tensile strength, excellent heat resistance, good rigidity at elevated temperature, good aging properties, also, good resistance to water, organic solvents, weak bases, and weak acids.
All these characteristics are coupled with relatively low cost.
Phenolic resins are used for low-cost parts requiring good electrical insulating properties, heat resistance, or chemical resistance.
The average shelf life of this resin is about 1 month at 21.1°C.
This can be extended by storing it in a refrigerator at 1.6 to 10°C.
Varying the catalyst(according to the thickness of the cast) and raising the cure temperature to 93°C will alter the cure time from as long as 8 h to as short as15 min.
Some shrinkage occurs in the finished casting(0.012 to 0.6 mm/mm), depending on the quantity of filler, amount of catalyst, and the rate of cure.
Faster cure cycles produce a higher rate of shrinkage.
Since the cure cycle can be accelerated, phenolics are used in short-run casting operations.
Cast phenolic parts are easily removed from the mold if the parting agents recommended by the supplier are used.
Posturing improves the basic properties of the finished casting.
Phenolic resins are found in myriad industrial products.
Phenolic laminates are made by impregnating one or more layers of a base material such as paper, fiberglass, or cotton with phenolic resin and laminating the resin-saturated base material under heat and pressure.
The resin fully polymerizes (cures) during this process forming the thermoset polymer matrix.
The base material choice depends on the intended application of the finished product.
Paper phenolics are used in manufacturing electrical components such as punch-through boards, in household laminates, and in paper composite panels.
Glass phenolics are particularly well suited for use in the high speed bearing market.
Phenolic micro-balloons are used for density control.
The binding agent in normal (organic) brake pads, brake shoes, and clutch discs are phenolic resin.
Synthetic resin bonded paper, made from phenolic resin and paper, is used to make countertops.
Another use of phenolic resins is the making of droplets, famously used in Brabant automobiles.
Phenolic resins are also used for making exterior plywood commonly known as weather and boil proof (WBP) plywood because phenolic resins have no melting point but only a decomposing point in the temperature zone of 220 °C (428 °F) and above.
Phenolic resin is used as a binder in loudspeaker driver suspension components which are made of cloth.
Higher end billiard balls are made from phenolic resins, as opposed to the polyesters used in less expensive sets.
Phenolic resins are used in a very wide range of industries because of their unique balance of strength, durability, heat resistance, and chemical stability, and their applications often involve environments where ordinary plastics or natural materials would fail. One of the most important uses is in the automotive and aerospace industries, where phenolic resins are incorporated into brake pads, clutch facings, and friction materials because they can withstand very high temperatures and continuous mechanical stress without losing their shape or performance.
They are also widely applied in the electronics and electrical sector, where their excellent insulating properties and flame resistance make them a preferred choice for circuit boards, switch housings, connectors, and other components that must resist electrical currents while also performing safely in heat-generating environments.
In the construction industry, phenolic resins are used as binders in insulation materials, laminates, and coatings because they provide strength, durability, fire resistance, and moisture resistance, which are all critical for building safety and longevity.
In addition to these technical applications, phenolic resins are also important in consumer goods and everyday materials.
They are used as binders in plywood, particleboard, and other engineered woods, ensuring that furniture and building panels remain strong and dimensionally stable over time.
Decorative laminates that cover countertops, floors, and wall panels are also often made with phenolic resins, which give them hardness, resistance to scratches, and long-lasting appearance.
Sometimes people select fibre reinforced phenolic resin parts because their coefficient of thermal expansion closely matches that of the aluminum used for other parts of a system, as in early computer systems[5] and Duramold.
The Dutch painting forger Han van Meagerness mixed phenol formaldehyde with his oil paints before baking the finished canvas, in order to fake the drying out of the paint over the centuries.
Atmospheric re-entry spacecraft use phenol formaldehyde resin as a key component in ablative heat shields (e.g. AVCOAT on the Apollo modules).
As the heat shield skin temperature can reach 1000-2000 °C, the resin pyrolizes due to aerodynamic heating.
This reaction absorbs significant thermal energy, insulating the deeper layers of the heat shield.
The outgassing of pyrolysis reaction products and the removal of charred material by friction (ablation) also contribute to vehicle insulation, by mechanically carrying away the heat absorbed in those materials.
TCC phenolic resins are found in a myriad of industrial products.
Phenolic Resin are made by impregnating one or more layers of the base material such as paper, fiberglass or carbon with phenolic resin and laminating the resin saturated base material under heat and pressure.
The resin fully polymerizes (cures) during this process.
The base material choice depends on the intended application of the finished product.
Phenolic Resins are used in manufacturing electrical components such as punch–through boards and household laminates.
Glass phenolics are particularly well-suited for use in the high-speed bearing market.
Phenolic micro-balloons are used for density control.
Snooker balls as well as balls from many table–based ballgames are also made from phenol formaldehyde resin.
The binding agent in normal (organic) brake pads, brake shoes and clutch discs are made of phenolic resin.
Another major use is in industrial products such as adhesives, coatings, and bonding agents, where phenolic resins provide excellent adhesion to metals, wood, and composites while also resisting chemicals and moisture.
They are also widely used in abrasive products, such as grinding wheels, sandpapers, and polishing discs, because they can securely bind abrasive grains while withstanding the frictional heat produced during grinding processes.
Foundries rely on phenolic resin-based binders for sand molds and cores, which must hold their shape under high temperatures during metal casting.
The phenolic resins most widely used are low molecular weight butylated resols, which contain phenolic hydroxyl groups and etherified and unetherified methylol groups.
The epoxy resins used have a molecular weight of 3000-4000 and therefore contain secondary hydroxyl groups.
Safety Profile Of Phenolic Resin:
Phenolic Resin, while highly valuable in many industries, also come with a range of potential hazards that must be carefully considered during their production, processing, and use, especially because they are made from phenol and formaldehyde, which are both toxic and irritating substances.
During manufacturing, workers can be exposed to formaldehyde vapors, which are known to be irritating to the eyes, nose, and throat, and prolonged or high-level exposure has been classified as carcinogenic to humans.
Even at low concentrations, formaldehyde can cause respiratory discomfort, coughing, and skin irritation, meaning that strict ventilation, personal protective equipment, and exposure controls are necessary in facilities where phenolic resins are produced or cured.
Another hazard comes from phenol itself, which is a corrosive chemical that can cause severe burns and tissue damage upon contact with the skin.
Phenolic Resin is also absorbed rapidly through the skin, which can lead to systemic toxicity affecting the central nervous system, liver, and kidneys.
This makes handling raw phenolic resin precursors particularly dangerous without gloves, protective clothing, and proper safety training.
In addition, the curing process of phenolic resins releases small amounts of volatile organic compounds (VOCs), including formaldehyde, which can contribute to poor indoor air quality if not properly managed.
