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| HS Code | 516041 |
| Chemical Name | Dicyclopentadiene |
| Cas Number | 77-73-6 |
| Chemical Formula | C10H12 |
| Molecular Weight | 132.20 g/mol |
| Appearance | White crystalline solid or colorless liquid |
| Odor | Camphor-like odor |
| Melting Point | 32-34 °C |
| Boiling Point | 170 °C |
| Density | 0.981 g/cm3 at 35 °C |
| Flash Point | 32 °C |
| Vapor Pressure | 1.4 mmHg at 20 °C |
| Vapor Density | 4.55 (air = 1) |
| Solubility In Water | Insoluble |
| Autoignition Temperature | 503 °C |
As an accredited Dicyclopentadiene factory, we enforce strict quality protocols—every batch undergoes rigorous testing to ensure consistent efficacy and safety standards.
| Packing | Dicyclopentadiene is supplied in 200 kg steel drums or 1,000 kg IBC totes, with nitrogen blanketing. |
| Container Loading (20′ FCL) | Load Dicyclopentadiene in 20′ FCL as UN-approved drums or IBCs, securely blocked, grounded, and segregated from ignition sources. |
| Shipping | Dicyclopentadiene is shipped as a flammable liquid under UN 2048, Class 3, Packing Group III. It is typically transported in steel drums, IBCs, or isotanks, often nitrogen-blanketed. Segregate from oxidizers, ground containers to prevent static sparks, and ensure good ventilation during loading and unloading. |
| Storage | Store dicyclopentadiene in tightly sealed, grounded containers under inert gas (e.g., nitrogen) to prevent peroxide formation and oxidation. Keep in a cool, dry, well-ventilated area away from heat, sparks, open flames, and strong oxidizers. Use explosion-proof equipment and regularly check containers for leaks or polymerization. |
| Shelf Life | Dicyclopentadiene has a shelf life of about one year if stored cool, dry, under inert gas, away from light and oxidizers. |
In integrated EPDM facilities, high-purity dicyclopentadiene is fed to a cracking section operated at 180–240°C with short vapour residence time to shift the DCPD/cyclopentadiene equilibrium toward monomer recovery. The recovered cyclopentadiene stream is distilled under reduced pressure to remove C5 codimers and is then reacted with an excess of 1,3-butadiene in a Diels-Alder adduction unit; the resulting 5-vinyl-2-norbornene is isomerised to ethylidene norbornene before fractionation. ENB-grade DCPD feed specifications commonly require 95 wt% minimum DCPD, with total C5 codimers below 2 wt% and residual peroxides below 50 ppm; cracker conversion is maintained at 92–97% per pass to limit re-dimerisation while avoiding thermal degradation. In EPDM polymerisation, ethylidene norbornene is introduced as a cure-site monomer at a final polymer mass fraction of 3.0–9.5 wt%; the concentration is adjusted according to vulcanisation kinetics required by the downstream converter. Higher ENB content accelerates sulfur cure and increases crosslink density but raises compound scorch sensitivity; lower ENB content reduces accelerator demand and improves heat ageing. Solution polymerisation in hexane at 30–70°C uses Ziegler-Natta or metallocene catalysts, with hydrogen as molecular weight modifier. After catalyst deactivation and steam stripping, the crumb is dried and baled. Compliance is established through ASTM D6047 for ENB determination, ISO 289-1:2015 for Mooney viscosity, ASTM D3568 for EPDM evaluation, and ISO 6502:2016 for cure properties. Terminal product types include automotive weatherseals, radiator hoses, single-ply roofing membranes, wire and cable insulation, thermoplastic vulcanizate modifiers, and extruded profiles for construction glazing. Batch-to-batch variation in DCPD feed peroxide content above 50 ppm is a known cause of reduced catalyst productivity and inconsistent ENB incorporation on continuous polymerisation lines.
To produce hydrogenated tackifying resins with a narrow softening-point window, technical-grade dicyclopentadiene is thermally polymerised in a high-pressure autoclave at 240–300°C and 0.8–2.0 MPa, with residence time adjusted to target a ring-and-ball softening point of 85–120°C. The feed may contain 85–95 wt% DCPD plus C5 aromatic comonomers; increasing aromatic comonomer content raises tack but reduces light stability. Polymerised resin is then hydrogenated in a fixed-bed reactor at 220–280°C and 5–15 MPa over sulfided Ni-Mo or supported palladium catalysts to reduce unsaturation and colour. Unhydrogenated grades exhibit Gardner colour above 4 after thermal ageing measured by ASTM D1544, which limits direct use in white or transparent adhesive systems. In ethylene-vinyl acetate hot-melt adhesives, DCPD tackifier content is compounded at 20–45 wt% with EVA, wax, and stabiliser in a co-rotating twin-screw extruder with an L/D 40:1 screw and barrel temperatures from 140–170°C. In styrenic block copolymer pressure-sensitive adhesives, DCPD resin loading is typically 10–30 wt% to raise peel adhesion without losing shear holding power. Compliance standards include FDA 21 CFR 175.105, FDA 21 CFR 176.170, EU 10/2011, and REACH Annex XVII; softening point is verified by ASTM E28-18. Terminal product types are hot-melt packaging adhesives, tape and label pressure-sensitive adhesives, hygiene construction adhesives, rubber tackifiers, and flexographic printing ink binders.
| Jurisdiction | Standard or regulation | Scope |
|---|---|---|
| United States | FDA 21 CFR 175.105 | Indirect food-contact adhesives |
| United States | FDA 21 CFR 176.170 | Paper and paperboard components in aqueous and fatty food contact |
| European Union | EU 10/2011 | Plastic materials and articles intended for food contact |
| European Union | REACH Annex XVII | Restriction of certain substances in articles |
| Global | ASTM E28-18 | Ring-and-ball softening point of hydrocarbon resins |
On reaction injection moulding lines producing large-area exterior parts, dicyclopentadiene monomer is conditioned at 25–35°C before being combined with a metathesis catalyst in a high-pressure impingement mixhead operating at 10–20 MPa. The two streams are mixed for 0.1–0.5 s and injected into a preheated mould held at 60–80°C; the polymerisation is ring-opening metathesis polymerisation, and the mould is typically demoulded after 2–6 min. Monomer specifications for RIM-grade DCPD require 98 wt% minimum DCPD, water content below 50 ppm, and oxygen content below 10 ppm because moisture and air deactivate the catalyst and produce surface tack on the moulded surface. Catalyst loading is supplied as a separate liquid stream at 0.1–0.5 wt% relative to monomer depending on mould fill time and part wall thickness; antioxidant addition is maintained at 0.1–1.0 wt% to prevent thermo-oxidative embrittlement. Mechanical validation is performed with ISO 527-2:2012 for tensile properties, ISO 178:2010 for flexural modulus, ISO 179-1:2010 for Charpy impact, ISO 75-2:2013 for heat deflection temperature, and UL 94 for flammability class. Published typical flexural modulus for unfilled PDCPD is 1.7–2.1 GPa; ultimate tensile strength is commonly reported between 40–50 MPa. Terminal product types include truck fenders, bus body panels, agricultural machinery hoods, telecommunications enclosures, industrial covers, and cast sanitary ware. Equipment experience from production lines indicates that failure to purge mould cavities with nitrogen before injection creates visible surface defects from catalyst deactivation at the flow front, while low monomer temperature below 15°C increases viscosity and causes metering pump cavitation.
At the first condensation stage, maleic anhydride is reacted with dicyclopentadiene-derived cyclopentadiene to form nadic structures that are subsequently esterified with propylene glycol or diethylene glycol at 190–215°C under nitrogen until an acid number of 15–35 mg KOH/g is reached. The DCPD modification is maintained at 10–20 wt% of finished resin solids; this substitution lowers residual hydroxyl content, improves hydrolytic resistance, and reduces styrene loss during open-mould lamination. The reactor is then vacuum-stripped at -0.08 MPa to residual water below 5 wt% and dissolved in styrene monomer at 35–45 wt% with inhibitor. Gel time is controlled by accelerator and initiator selection; for open-mould laminating, cobalt naphthenate and methyl ethyl ketone peroxide are metered separately at the spray gun. Compliance for fabrications is based on EN 13121-3:2016 for FRP tanks and vessels, ASTM D4097-19 for chemical-resistant contact-moulded tanks, ISO 527-4:1997 for tensile properties, and ISO 14125 for flexural properties. Terminal product types are chemical storage tanks, ducts and scrubbers, marine hulls, sewage treatment covers, architectural gel-coat backup laminates, and fibreglass bathroom fixtures. Operational limits include an increase in resin viscosity at DCPD contents above 20 wt%, which complicates wet-out in closed-mould infusion, and higher exotherm in thick-section castings.
Optical-grade norbornene produced from DCPD-derived cyclopentadiene requires purification to 99.5 wt% minimum norbornene before copolymerisation with ethylene. Dicyclopentadiene is cracked at 180–220°C and the cyclopentadiene stream is reacted with ethylene in a Diels-Alder reactor at 150–200°C and 5–20 MPa; the crude norbornene is then fractionated to remove benzene, toluene, and residual cyclopentadiene to below 100 ppm. In the subsequent metallocene-catalysed solution polymerisation, norbornene content is controlled between 30–60 mol% to produce cyclic olefin copolymers with glass transition temperatures from 78–165°C; increasing norbornene content raises glass transition temperature and moisture resistance while reducing melt flow. Melt flow rate is determined by ISO 1133-1:2022, Vicat softening temperature by ISO 306:2022, and water absorption by ISO 62:2008. Medical and pharmaceutical grade materials are tested against USP <661>, FDA 21 CFR 177.1520, and EU 10/2011 for food-contact and parenteral packaging applications. Terminal product types are prefillable syringes, diagnostic microtiter plates, pharmaceutical blister film, optical lenses, and laboratory cuvettes. Residual cyclopentadiene in norbornene above 100 ppm is a known cause of reduced metallocene catalyst productivity during continuous polymerisation campaigns.
Following Diels-Alder addition of cyclopentadiene to maleic anhydride in a closed-loop reactor at 60–120°C, the resulting nadic anhydride is purified by solvent stripping and blended with liquid anhydride hardeners for epoxy curing. In diglycidyl ether of bisphenol A epoxy resin with an epoxide equivalent weight of 180–190 g/eq, the anhydride hardener is added at 0.80–0.90 anhydride groups per epoxide group, corresponding to 75–90 phr depending on accelerator type. Tertiary amine accelerators such as benzyldimethylamine are used at 0.5–2.0 phr to shorten gel time. The liquid formulation is degassed under vacuum at 60°C and cured in a two-stage cycle of 100–120°C for 2 h followed by 150–180°C for 4 h to achieve full conversion and elevated glass transition temperature. Electrical and mechanical validation is performed with ASTM D149-20 for dielectric breakdown, ASTM D257-14 for volume resistivity, and IEC 60093 for surface and volume resistivity. Terminal product types are high-voltage transformer bushings, epoxy castings for switchgear insulation, filament-wound composite tubes, and high-temperature potting compounds. Anhydride hardeners of this class hydrolyse in humid air above 0.05 wt% moisture pickup, forming free acid that retards cure and lowers dielectric strength; storage under dry nitrogen and sealed process lines are required.
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Dicyclopentadiene (DCPD), CAS 77-73-6, is a C10H12 cyclic diene dimer recovered from the C5 steam-cracking fraction of naphtha crackers. The commercial product is supplied under model designations that reflect nominal purity—commonly DCPD 95, DCPD 85, and DCPD 75—and is used as a reactive building block for hydrocarbon resins, unsaturated polyester resins, cycloolefin copolymers, norbornene, ethylidene norbornene, flame-retardant intermediates, and agricultural intermediates. The high-purity material is predominantly the endo isomer, with a freezing point in the range 32–34 °C, a boiling point of 170 °C at 101.3 kPa, and a density near 0.98 g/cm³ at 20 °C. Technical-grade DCPD is a complex mixture of DCPD, cyclopentadiene codimers, and minor C5–C6 olefins; its lower purity is not a defect but an economic choice for resin polymerisation where polar impurities co-react into the resin matrix. The chief specification variables are purity, endo/exo ratio, water content, APHA colour, and inhibitor concentration. These variables shift the thermal polymerisation window, the ring-opening metathesis polymerisation activity, and the storage stability of the feedstock.
The endo isomer is the kinetically favoured dimer formed during the Diels–Alder dimerisation of cyclopentadiene, while the exo isomer is thermodynamically more stable. Commercial DCPD produced from C5 cracked gas typically contains endo/exo ratios above 90:10; residual cyclopentadiene is reduced by fractional distillation. In ring-opening metathesis polymerisation (ROMP) using ruthenium or molybdenum initiators, the exo isomer exhibits a significantly higher propagation rate because the unfavourable steric interaction between the cyclopentene ring and the metal alkylidene is reduced. Published kinetic studies indicate that the ratio of propagation rate constants can exceed one order of magnitude between exo and endo isomers. As a result, resin-grade DCPD with a lower exo content may require higher initiator loading or longer batch hold times in a production reactor. This is not a purity failure but a specification shift that must be tracked when the C5 separation column feed composition changes. Production-scale experience shows that endo/exo variability in the same nominal DCPD grade can alter ROMP peak exotherm timing by several minutes, which is material for reactor temperature control and emergency cooling capacity.
DCPD polymerises thermally through both radical and cationic pathways. The radical pathway is suppressed by hindered phenols such as 2,6-di-tert-butyl-4-methylphenol (BHT) or by 4-tert-butylcatechol (TBC), while the cationic pathway is accelerated by dissolved acidic species, including some phenolic oxidation products. In a bulk resin reactor, the onset of thermal runaway is influenced by inhibitor concentration, oxygen exposure, and reactive codimer content. Production-scale bulk polymerisation of DCPD for polydicyclopentadiene (PDCPD) is typically carried out with a two-component ROMP system in a closed mould or reaction injection moulding press, where the liquid feed must remain below the inhibitor-depletion temperature. Thermal initiation above 130 °C can generate exotherms that exceed the heat-transfer capacity of a jacketed reactor unless inhibitor loading is increased. High-purity DCPD is stored at 35–45 °C to remain liquid, while inhibitor concentration is maintained at ≥ 50 mg/kg; prolonged storage above 50 °C is avoided because thermal oligomerisation accelerates. When technical-grade DCPD is used for hydrocarbon resin production, the higher codimer content lowers the freezing point and allows handling at lower temperature, but the reactive cyclopentadiene fraction can accelerate exotherm. In continuous thermal polymerisation of DCPD-containing C5 streams, the reactor skin temperature and quench oil circulation rate must be matched to feed purity; published operating guidance for such units typically specifies 140–180 °C reactor temperatures for resin softening points of 100–160 °C.
| Parameter | High-Purity DCPD 95 | Technical DCPD 85 | Resin-Grade DCPD 75 |
|---|---|---|---|
| DCPD content by GC | ≥ 95 wt% | 83–92 wt% | 70–85 wt% |
| Endo/exo ratio | ≥ 93:7 | ≥ 90:10 | not tightly controlled |
| Freezing point | 32–34 °C | depressed; varies with codimer content | depressed; varies with codimer content |
| APHA colour, ASTM D1209 | ≤ 50 | ≤ 100 | ≤ 150 |
| Water, ASTM E203 | ≤ 200 mg/kg | ≤ 300 mg/kg | ≤ 500 mg/kg |
| Inhibitor content | 50–150 mg/kg | 50–150 mg/kg | 50–200 mg/kg |
| Primary use | norbornene, ENB, ROMP feedstocks | hydrocarbon resins, polyester modifiers | resin manufacturing, cost-sensitive formulations |
DCPD differs from linear conjugated dienes such as butadiene and isoprene in that its two double bonds are geometrically constrained in a cyclic structure. The result is a higher boiling point of 170 °C compared with −4.4 °C for butadiene and a higher flash point of 32 °C, which simplifies bulk liquid handling and reduces pressure-rated storage requirements. In polymerisation, DCPD does not provide the low glass-transition elastomer character of butadiene; instead it raises glass-transition temperature and hardness of the resulting polymer. In unsaturated polyester resins, partial replacement of phthalic or maleic anhydride by DCPD-derived intermediates increases heat distortion temperature and reduces styrene emission due to lower resin viscosity at equivalent unsaturation. When DCPD is used as a termonomer in EPDM, the cure rate is slower than ethylidene norbornene-containing EPDM because the norbornene double bond of ENB is more accessible to sulfur vulcanisation; DCPD-based EPDM historically offered lower catalyst consumption and better cost for less demanding moulding applications. These contrasts explain why DCPD is selected when cyclic rigidity, high resin softening point, or low vapour pressure is required, while butadiene is selected when low-temperature flexibility and high diene reactivity are required.
| Monomer | Molecular formula | Molecular weight | Boiling point | Freezing point | Structural character |
|---|---|---|---|---|---|
| DCPD | C10H12 | 132.2 g/mol | 170 °C | 32–34 °C endo | cyclic dimer, rigid backbone |
| Cyclopentadiene | C5H6 | 66.1 g/mol | 41.5 °C | −97 °C | reactive diene; dimerises readily |
| Butadiene | C4H6 | 54.1 g/mol | −4.4 °C | −108.9 °C | linear conjugated diene |
| Isoprene | C5H8 | 68.1 g/mol | 34.1 °C | −145.9 °C | branched conjugated diene |
EPDM producers select DCPD as a termonomer when lower compound cost and adequate scorch safety are more important than maximum cure rate. DCPD-based EPDM grades exhibit a lower unsaturated carbon concentration in the side chain than ENB-based grades, which reduces sulfur cure rate and improves resistance to reversion in thick sections. The slower vulcanization is normally offset by higher accelerator dosage or by blending with ENB-EPDM. Because DCPD is less expensive per tonne than ENB and the DCPD termonomer produces lower polymerisation catalyst residues in some Ziegler–Natta processes, DCPD-EPDM remains used in moulded goods where maximum cure rate is not required. Published data for compounded properties is widely available from EPDM producers; typical Mooney viscosity ranges and cure curves are product-specific and are supplied under individual technical data sheets rather than generic standards.
When DCPD is incorporated into an unsaturated polyester backbone, the cured network contains fewer ester linkages per unit chain length, which reduces water uptake and raises heat distortion temperature. The resin producer must control addition level because excess DCPD raises resin softening point beyond the solubility range of styrene monomer, causing phase separation. Typical DCPD modification levels reported in technical literature range from 5 wt% to 30 wt% of the polyester charge. Cured-resin property shifts are measured by ASTM D648 for heat distortion temperature and ASTM D570 for water absorption. This application consumes DCPD as a lower-volatility alternative to dicyclopentadiene-derived maleic adducts, and it competes with isophthalic acid and terephthalic acid modifications for corrosion-resistant and marine-grade laminates.
Hydrocarbon resin producers blend DCPD with piperylene concentrate, methylcyclopentadiene dimer, or aromatic C9 streams to tailor softening point, molecular weight distribution, and colour. DCPD-rich resins typically exhibit higher softening points at equivalent molecular weight than C5 piperylene resins because the condensed bicyclic structure increases chain stiffness. The polymerisation is Lewis-acid catalysed in a continuous stirred-tank reactor at 30–70 °C; the resulting oligomer is quenched, washed, and stripped to remove unreacted monomers. Batch-to-batch differences in the DCPD content of the C5 feed change the required catalyst feed rate and can shift the resin Gardner colour if the feed contains entrained cyclopentadiene. The product slate is typically classified by softening point, such as 90–110 °C, 111–130 °C, and 131–160 °C ranges, and by Gardner colour. DCPD resins are used in adhesives, road marking, rubber compounding, and printing inks, where higher softening point and lower tackifying resin loading are valued. Published data for proprietary DCPD resin formulations is limited; the ranges stated here reflect general commercial technical datasheet values rather than a single producer’s specification.
DCPD storage is constrained by four variables: temperature, oxygen exposure, inhibitor depletion, and water ingress. Because the high-purity material freezes at 32–34 °C, storage tanks are maintained at 35–45 °C with heated transfer lines and pump tracing. At the same time, thermal dimerisation of any residual cyclopentadiene and thermal oligomerisation of DCPD accelerate above 60 °C; therefore, bulk storage above 50 °C is normally avoided unless continuous consumption is rapid. Nitrogen blanketing at 0.5–2.0 kPa gauge prevents oxygen ingress and moisture pickup; oxygen may promote peroxide formation, which can generate free radicals and initiate uncontrolled polymerisation. Inhibitor concentration should be monitored at receiving and after long storage; 4-tert-butylcatechol concentration below 50 mg/kg in a stored high-purity DCPD tank can allow radical polymerisation at a hot spot such as a steam coil surface. Water above 200 mg/kg can form ice crystals in vent lines and cause corrosion in carbon steel storage. Storage vessels are typically carbon steel or stainless steel; copper and copper alloys should be avoided because copper accelerates peroxide decomposition and can precipitate polymer fouling. Rotary positive-displacement pumps with mechanical seals are used rather than centrifugal pumps if the liquid is near its freezing point. These limits are established from standard industrial practice and supplier safety data sheets rather than a single test standard.
