| HS Code | 142793 |
| Chemical Name | Polybutadiene |
| Cas Number | 9003-17-2 |
| Appearance | Clear to light yellow viscous liquid or solid |
| Density | 0.90 - 0.92 g/cm³ |
| Glass Transition Temperature | -85°C to -60°C |
| Solubility | Soluble in benzene, toluene, hexane, and other hydrocarbons; insoluble in water and alcohols |
| Molecular Weight | 1,000 - 100,000 g/mol (depending on grade) |
| Viscosity | 1,000 - 100,000 mPa·s at 25°C (grade-dependent) |
| Refractive Index | 1.514 - 1.520 |
| Tensile Strength | 1 - 15 MPa (depending on formulation) |
| Elongation At Break | 100% - 500% (depending on formulation) |
| Hardness | 40 - 95 Shore A |
| Thermal Decomposition Temperature | Approximately 300°C |
| Dielectric Constant | 2.4 - 2.6 at 1 MHz |
As an accredited Polybutadiene (PB) Resin factory, we enforce strict quality protocols—every batch undergoes rigorous testing to ensure consistent efficacy and safety standards.
| Packing | Polybutadiene (PB) Resin is packaged in 25 kg lined kraft paper bags, palletized and shrink-wrapped for safe handling and transport. |
| Container Loading (20′ FCL) | Polybutadiene (PB) resin loaded in 20′ FCL as palletized, heat-sealed bags, secured properly to prevent shifting and ensure safe transport. |
| Shipping | Polybutadiene (PB) Resin is shipped in sealed drums, fiberboard boxes, or bulk containers to prevent contamination and moisture ingress. Keep away from heat, sparks, and oxidizing agents. Use dry, ventilated transport with proper labeling and secure loading. Avoid prolonged exposure to sunlight and store below recommended temperatures during transit. |
| Storage | Store Polybutadiene (PB) Resin in a cool, dry, well-ventilated area away from direct sunlight, heat, and ignition sources. Keep containers tightly sealed to prevent moisture absorption and contamination. Avoid contact with oxidizing agents. Maintain temperatures between recommended ranges to prevent polymerization or degradation. Follow manufacturer guidelines for shelf life and handling. |
| Shelf Life | Polybutadiene resin has a shelf life of 6–12 months when stored cool, dry, and sealed, away from light and oxygen. |
In passenger radial tread formulations, high-cis polybutadiene is introduced at 20–50 phr to reduce hysteresis at 60 °C and improve abrasion resistance measured according to DIN 53516 or ISO 4649. The polymer supplied with cis-1,4 content above 96% and Mooney viscosity ML 1+4 at 100 °C in the range 38–55 MU is first masticated in an intermeshing rotor internal mixer with a net chamber volume of 55–270 L and a fill factor of 0.70–0.75. Two-stage mixing is necessary: the first non-productive stage combines BR with carbon black or silica, processing oil, zinc oxide, stearic acid and antidegradants to a dump temperature of 150–165 °C; the second stage adds sulphur curatives, accelerators and silane coupling agents at 95–110 °C to avoid scorch. In silica-filled systems, the non-polar high-cis BR surface lacks adsorption sites for silanol groups, so bis(triethoxysilylpropyl) tetrasulphide is added at 6–10 wt% of silica. Mixing energy input in the first stage typically reaches 0.25–0.35 kWh/kg depending on rotor speed and ram pressure; overheating above 165 °C causes premature silane reaction and raises compound viscosity. A critical formulation threshold is observed at BR loadings above 50 phr: wet traction indicator tan δ at 0 °C falls below 0.15, and the DIN abrasion loss begins to plateau while low-temperature flexibility improves only marginally. From a processing standpoint, high-cis BR has cold-flow tendency; bales stored above 35 °C or under high stacking pressure deform, which complicates automatic feed systems. The compound Mooney viscosity increases by 5–12 MU when BR replaces natural rubber at equal phr, and mill roll behaviour shifts from banding to bagging above 70 phr BR. Table 1 compares high-cis and high-vinyl polybutadiene in the same silica-filled tread model compound.
| Parameter | High-cis BR | High-vinyl BR | Test method |
|---|---|---|---|
| Glass transition temperature | -108 to -100 °C | -50 to -30 °C | ISO 11357-2 |
| DIN abrasion loss | 80–110 mm³ | 100–140 mm³ | DIN 53516 |
| tan δ at 0 °C | 0.15–0.20 | 0.30–0.45 | ISO 6721-1 |
| tan δ at 60 °C | 0.08–0.12 | 0.12–0.16 | ISO 6721-1 |
| Mooney ML 1+4 at 100 °C | 38–55 MU | 40–65 MU | ISO 289-1 |
Subsequent single-screw extrusion of the tread profile is performed at 80–95 °C die head temperature and 15–25 m/min take-off speed; BR-rich compounds exhibit lower die swell than NR-rich controls but may require a drawdown below 8% to prevent surface tearing. Extrudate porosity rises if moisture content exceeds 0.3 wt%, so silica-filled BR compounds are pre-dried or vented during extrusion.
In high-impact polystyrene (HIPS), polybutadiene rubber is dissolved in styrene before thermal or mass-suspension polymerization. Phase separation begins at 5–12 wt% rubber, and the final morphology depends on shear history, phase inversion and grafting. Rubber particle size in HIPS is typically 0.5–5 µm, with a bimodal distribution often preferred: large particles of 2–5 µm absorb energy and small particles of 0.5–1.5 µm maintain gloss. The gel content of the rubber phase is 15–30 wt%, and the swelling index measured in toluene ranges from 10–20. In ABS produced by emulsion or bulk routes, polybutadiene latex particles are 0.2–1 µm, and the grafted styrene-acrylonitrile shell provides interfacial adhesion. Notched Izod impact according to ASTM D256 improves with rubber content but modulus and melt flow fall. A processing boundary exists during devolatilization of HIPS: temperatures above 240 °C or residence times beyond 20 min cause rubber crosslinking, which raises gel content and reduces die swell; oxygen ingress accelerates this degradation. In injection moulding of ABS, barrel temperatures above 250 °C cause free butadiene double bonds to degrade, generating discoloration and volatiles. The impact transition also depends on rubber particle size; polybutadiene particles below 0.2 µm are ineffective as craze initiators in HIPS, while particles above 5 µm reduce surface gloss and notched impact. Table 2 gives typical property windows for HIPS and ABS impact modification systems.
| Parameter | HIPS typical window | ABS typical window | Test method |
|---|---|---|---|
| Polybutadiene content | 5–12 wt% | 10–20 wt% | solvent extraction |
| Rubber particle size | 0.5–5 µm | 0.2–1 µm | TEM |
| Gel content | 15–30 wt% | 30–70 wt% | toluene insolubles |
| Swelling index | 10–20 | 8–15 | toluene swelling |
| Notched Izod impact at 23 °C | 10–25 kJ/m² | 20–40 kJ/m² | ISO 180 |
| Melt flow rate | 4–12 g/10 min | 10–40 g/10 min | ISO 1133-1 |
Hydroxyl-terminated polybutadiene (HTPB) with hydroxyl value 40–50 mg KOH/g and viscosity 1.5–5.0 Pa·s at 30 °C serves as the binder matrix for composite propellant, where total solids loading reaches 86–88 wt%: ammonium perchlorate 70–75 wt% and aluminium powder 10–18 wt%. Mixing is performed in a vertical planetary mixer under vacuum of 5–20 mbar and jacket temperature 40–60 °C to avoid frictional heating and to remove entrapped air. Pot life is governed by the isocyanate curative; with isophorone diisocyanate and dibutyltin dilaurate at 0.005–0.02 wt%, the viscosity doubles within 4–8 h. The NCO:OH ratio is controlled between 0.90 and 1.10; at values below 0.90 the cured binder exhibits low tensile strength and high permanent set, while above 1.10 unreacted isocyanate leads to humidity sensitivity and brittleness. Moisture must be held below 0.05 wt% of the binder because water reacts with isocyanate and forms voids in the cast grain. Published data for this specific configuration is limited, but the processing boundary is clear: solids loading above 88 wt% increases end-of-mix viscosity beyond 20 kPa·s, causing incomplete wet-out of oxidizer particles and uneven ballistic reproducibility. Oxidizer particle size distribution is adjusted from 200 µm to 5 µm multimodal; coarse AP improves flow and reduces viscosity, while fine AP improves burning rate but increases yield stress. The end-of-mix slurry is degassed and cast into motors under vacuum, and cure is executed at 55–65 °C for 5–7 days to minimize stress gradients across thick webs.
Thermosetting 1,2-polybutadiene resins are formulated for RF transformer encapsulation and multilayer capacitor sealing where low dielectric constant and low moisture uptake are required. The resin has a 1,2-vinyl content above 85%, a number-average molecular weight between 1,000 and 3,000 g/mol, and cures via peroxide initiation at 120–180 °C. Peroxide choice is constrained: dicumyl peroxide is added at 1–3 wt%, and cure must be staged with an initial ramp at 100–120 °C to avoid exothermic runaway because the vinyl addition reaction releases significant heat. The dielectric constant measured according to ASTM D150 at 1 MHz is 2.4–2.6, and the dissipation factor is below 0.003. Volume resistivity per ASTM D257 exceeds 10^15 Ω·cm. The cured matrix has high crosslink density and may exhibit shrinkage of 2–5%, which is accommodated by flexible mould design or coupling agents. Amine-based additives are avoided because amines retard the peroxide cure and leave unreacted double bonds that increase dielectric loss and moisture absorption. The formulation is hygroscopic; filler addition of silica reduces linear expansion but raises viscosity. In sections thicker than 5 mm, peak exotherm must be maintained below 200 °C to prevent thermal cracking.
High-cis BR is the base elastomer for solid two-piece and multilayer golf ball cores because its ZDMA-peroxide cure yields high rebound and moderate compression. Zinc dimethacrylate loading between 20 and 40 phr in BR with Mooney ML 1+4 at 100 °C of 30–45 MU produces a semi-interpenetrating zinc ion network during compression moulding at 150–170 °C for 15–25 min. The dispersion of ZDMA is the primary processing constraint: undispersed agglomerates above 10 µm act as fracture initiators and reduce core durability. Two-roll milling or internal mixing must achieve a sheet temperature of 70–90 °C so that ZDMA softens and shears into the BR phase without polymerizing prematurely. Peroxide selection matters; 1,1-di-(tert-butylperoxy)-3,3,5-trimethylcyclohexane at 0.5–1.0 phr provides sufficient cure without excessive scorch at milling temperatures. Resilience measured by ASTM D2632 is 75–85%, and core hardness is 30–45 Shore D. The compression can be adjusted by altering ZDMA loading: an increase of 10 phr typically raises ATTI compression by 8–12 points, but published data for this specific configuration is limited. Processing compatibility with cover injection is critical; the cured core must withstand cover melt temperature of 180–220 °C without post-curing, which is achieved by complete peroxide decomposition during core cure and by adding 0.2–0.5 phr antioxidant.
In fabric-reinforced conveyor belt cover compounds, high-cis BR is blended with natural rubber or SBR at 20–50 phr to reduce cut growth and improve abrasion resistance. The cover compound is mixed in an internal mixer with carbon black at 40–60 phr and plasticizer at 5–15 phr; dump temperature is limited to 150–160 °C because BR degrades by thermomechanical chain scission above 170 °C. The cured cover is evaluated for tensile strength, elongation, and abrasion loss per ISO 37 and ISO 4649. Ozone resistance is a boundary condition: unprotected BR covers crack under 100 pphm ozone within 24–48 h in bent-loop tests, so para-phenylene diamine antiozonant at 2–3 phr and microcrystalline wax at 1–2 phr are required. Cut growth resistance per ASTM D813 improves with BR addition up to 50 phr; beyond this, the cover compound loses tack and becomes difficult to calendar into textile carcass. Calender roll temperature is set at 60–80 °C because BR-containing sheets bag below 50 °C and tear above 90 °C. Fabric adhesion to BR-rich cover compounds needs resorcinol-formaldehyde-silica bonding systems; otherwise peel adhesion falls below 8 N/mm under ISO 252.
High-cis BR is incorporated into injection-moulded shoe sole compounds at 20–40 phr to improve flex fatigue and abrasion resistance without excessive loss of wet slip. The base elastomer blend is typically NR/SBR, and BR raises low-temperature flexibility; the glass transition of high-cis BR is near -108 °C. Mixing is conducted in a tangential internal mixer with a dump temperature of 130–150 °C, and curatives are added on a two-roll mill at 60–70 °C to prevent scorch. Injection moulding uses screw barrel temperatures of 70–90 °C and mould temperatures of 160–175 °C; cure time is 3–6 min depending on sole thickness. The Ross flex crack resistance measured by ASTM D1052 improves with BR addition up to 40 phr, while DIN abrasion loss per ISO 4649 decreases by 15–30% relative to an all-NR control. A process boundary appears above 40 phr BR: the uncured compound becomes too elastic, leading to knit-line weakness at multiple injection gates and dimensional instability after demoulding. Hardness is maintained at 55–65 Shore A with filler and oil adjustments. Ozone protection remains necessary; BR-containing soles require 2–3 phr antiozonant and 1–2 phr wax, or surface cracking appears after 6–12 months of outdoor exposure.
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Among hydrocarbon thermoset modifiers, low-molecular-weight liquid polybutadiene (PB) resin is supplied as a clear to pale-amber prepolymer with a predominantly 1,2-vinyl microstructure when high reactivity is required. Commercial reactive grades are typically defined by number-average molecular weight of 1,000–5,000 g/mol, Brookfield viscosity at 25 °C of 500–50,000 mPa·s per ISO 3219:2021, and 1,2-vinyl content of 70–90 mol% by infrared spectroscopy per ISO 12965:2019. The hydrocarbon backbone contains no ester or urethane linkages, which distinguishes the material from unsaturated polyester and acrylated epoxy resins. Commercial product designations often encode nominal viscosity or molecular weight, such as the B-series liquid polybutadienes and maleinized PB adducts; because 1,2-vinyl content and molecular weight distribution vary among suppliers, the certificate of analysis rather than the product code is used for formulation control. In peroxide-cured elastomer compounds, the pendant vinyl groups participate in free-radical addition, while the 1,4 repeat units contribute chain flexibility and lower glass-transition temperature. The product is therefore positioned as a multifunctional reactive plasticizer, coagent, and dielectric matrix modifier rather than as a high-molecular-weight finished rubber. Low-vinyl liquid PB grades, with 1,2-vinyl content below 30 mol%, are used where limited crosslinking and low viscosity are required; high-vinyl grades above 70 mol% are used where high crosslink density and thermal resistance are required.
The pendant 1,2-vinyl group is the dominant cure site in peroxide-crosslinked PB resin systems. During cure, the terminal vinyl group forms tertiary carbon radicals that recombine into a dense hydrocarbon network; the internal 1,4 units remain largely flexible. A shift from 70 mol% to 90 mol% 1,2-vinyl content raises the peak torque in a moving die rheometer by approximately 15–25% when tested at 180 °C per ASTM D5289-19, reflecting higher crosslink density. The same structural shift increases the glass-transition temperature of the cured network from roughly -15 °C to +5 °C as measured by differential scanning calorimetry per ASTM D3418-21. The processing conflict is rheological: higher 1,2-vinyl content raises the room-temperature viscosity of the liquid resin, which complicates high-solids adhesive mixing and reduces wet-out on glass fabric. On twin-screw compounding lines with L/D 40–52, barrel temperatures above 120 °C are often required to lower viscosity sufficiently for injection into the melt, but prolonged residence above 140 °C can initiate thermal polymerization of the vinyl groups and gel the feed zone. This creates an operating window of approximately 120–135 °C for high-vinyl grades, with screw speed limited to 200–400 min⁻¹ on 25–40 mm co-rotating twin-screw extruders. Published data for a specific machine configuration is limited, but the window is consistent with supplier processing guides and indicates that temperature control within ±5 °C is required to avoid gel formation.
In halogen-free copper-clad laminate applications, high-vinyl PB resin is blended with low-dielectric thermoplastic elastomers and flame-retardant fillers to replace epoxy resin in the hydrocarbon dielectric layer. The absence of polar ester, hydroxyl, and epoxy groups reduces moisture uptake and lowers the dielectric constant. Formulations containing 25–50 phr PB resin and treated silica often exhibit a dielectric constant of 2.4–2.7 and a dissipation factor below 0.003 at 10 GHz when tested by split-post resonator per ASTM D2520-21 or supplier-specific methods. The resin also increases the crosslink density of the B-staged prepreg during lamination. Press cycles are typically held at 190–210 °C for 90–150 min under 2.0–4.0 MPa hydraulic pressure; the exotherm from vinyl addition can raise the center-line temperature by 8–15 °C, so press controls must maintain setpoint within ±5 °C to prevent uncontrolled advance and void formation. In contrast to epoxy resin, PB resin does not require dicyandiamide or amine curing agents, which removes nitrogen-containing residues that can increase dielectric loss. However, the hydrocarbon matrix is more combustible, so formulations require brominated or phosphorus-based flame retardants at higher loadings than epoxy systems. The glass-transition temperature of the cured laminate is typically 180–220 °C when measured by dynamic mechanical analysis per IPC-TM-650 2.4.24.4, which is lower than some high-Tg epoxy systems but adequate for lead-free solder assembly.
The replacement of epoxy-acrylate binders with liquid PB resin in UV-curable solder masks becomes technically viable only when oxygen inhibition is controlled. The vinyl addition reaction is strongly inhibited by atmospheric oxygen at the film surface, leaving a tacky surface layer if the cure dose is below 500 mJ/cm² in the UVA range. Inert-gas blanketing with nitrogen containing less than 100 ppm oxygen or the addition of paraffin wax at 0.5–1.0 wt% restores surface cure. Under these conditions, PB resin imparts lower moisture absorption and better resistance to alkaline gold-plating baths than epoxy acrylates, but the acrylate-free formulation does not develop the same pencil hardness; cured films typically require post-UV thermal cure at 150 °C for 60 min to reach a pencil hardness of H–2H per ASTM D3363-20. The absence of bisphenol A is a regulatory advantage under EU 2018/213 and REACH 1907/2006/EC, but migration testing for food-contact use requires verification under FDA 21 CFR 175.300 for resinous and polymeric coatings.
On production-scale rubber compounding lines, liquid PB resin is added as a peroxide coagent and processing aid in EPDM, hydrogenated nitrile, and polybutadiene rubber compounds. The material is injected into the internal mixer after the polymer has masticated, typically at 100–120 °C dump temperature, to avoid premature vinyl crosslinking. In a laboratory internal mixer with 1.5 L chamber volume, addition of 5–15 phr high-vinyl PB resin reduces the compound Mooney viscosity by 10–20 MU per ASTM D1646-19a and increases the delta torque in a moving die rheometer by 15–30% at 180 °C, indicating a higher final crosslink density. The scorch safety of the compound is retained if the resin is added after carbon black and oil dispersion, but the resin can migrate to the surface of uncured sheet if the compound is stored above 35 °C for more than 72 h. In peroxide-cured EPDM extruded profiles, the use of PB resin at 10 phr improves tear strength by 10–20% when tested per ASTM D624-20, while reducing compression set at 150 °C for 70 h by 5–10 percentage points per ASTM D395-18. The trade-off is reduced low-temperature flexibility because the high vinyl content raises the glass-transition temperature of the cured rubber phase; for applications requiring -40 °C low-temperature service, a low-vinyl PB resin or a higher-molecular-weight polybutadiene rubber should be selected.
The unmodified high-1,2 PB resin differs from maleinized polybutadiene in polarity, adhesion, and dielectric behavior. Maleinized PB resins contain grafted maleic anhydride groups at acid values of 20–50 mg KOH/g, which improve adhesion to metal and glass substrates but increase moisture sensitivity and dielectric constant. Unmodified PB resin has an acid value below 1 mg KOH/g, which is preferred for low-loss electrical laminates and moisture-resistant coatings. Compared with styrene-butadiene rubber/resin solutions, liquid PB resin has a lower aromatic content and a lower refractive index, but it lacks the styrenic hard phase that contributes room-temperature mechanical strength. In terms of rheology, high-vinyl PB resin at 25 °C exhibits Newtonian behavior up to shear rates of 100 s⁻¹, whereas SBR solutions are more shear-thinning. The following representative ranges illustrate the differences.
| Property | Test method | High-vinyl PB resin | Maleinized PB resin | SBR resin |
|---|---|---|---|---|
| Number-average molecular weight | ISO 16014-1:2019 | 1,000–5,000 g/mol | 1,000–5,000 g/mol | 5,000–15,000 g/mol |
| 1,2-vinyl content | ISO 12965:2019 | 70–90 mol% | 60–80 mol% | 10–30 mol% |
| Acid value | ASTM D974-21 | <1 mg KOH/g | 20–50 mg KOH/g | <1 mg KOH/g |
| Glass-transition temperature | ASTM D3418-21 | -20 to +5 °C | -20 to +20 °C | -30 to +10 °C |
| Viscosity at 25 °C | ISO 3219:2021 | 500–50,000 mPa·s | 1,000–100,000 mPa·s | 1,000–10,000 mPa·s |
| Dielectric constant at 10 GHz | ASTM D2520-21 | 2.4–2.7 | 2.8–3.2 | 2.9–3.4 |
| Moisture absorption, 24 h | ASTM D570-22 | <0.05% | 0.1–0.3% | 0.1–0.5% |
Migration resistance in pressure-sensitive adhesives and heat-seal coatings is controlled by cure conversion and the low-molecular-weight fraction. Uncured PB resin species with molecular weight below 500 g/mol can migrate through polyolefin films under accelerated storage at 60 °C for 10 days, producing visible surface bloom. Extraction testing per FDA 21 CFR 177.1520 for olefin polymers may be required when the resin is used in food-contact rubber articles; total hexane extractables should be below the applicable regulatory limit. In adhesive formulations, the combination of high-vinyl PB resin with tackifying hydrocarbon resins at 50–70 wt% raises loop tack and peel adhesion on stainless steel per ASTM D6195-22 and ASTM D3330-20, but the final peel strength depends strongly on the coating thickness and cure dose. The high unsaturation of the PB backbone makes long-term hot-melt stability poorer than saturated hydrocarbon resins; holding the adhesive at 170 °C for more than 24 h can double viscosity and reduce 180° peel adhesion by 20–30%. Nitrogen-blanketed tanks and temperature limits below 150 °C are therefore standard on hot-melt coating lines.
Oxidative degradation of PB resin follows a free-radical chain mechanism initiated by allylic hydrogen abstraction. The oxidation induction time at 190 °C, measured by differential scanning calorimetry per ASTM D3895-19, drops below 5 min in unstabilized high-vinyl PB resin. Addition of a hindered phenol antioxidant at 0.2–0.5 wt% extends the OIT to 30–60 min; a secondary phosphite at 0.1–0.3 wt% improves color retention during high-shear mixing. For continuous lamination, the antioxidant package must not contain basic amines, because residual amines can accelerate the thermal polymerization of vinyl groups and shift the press gel time. The use of zinc stearate as a mold release agent is compatible at normal levels, but cobalt-based driers used in unsaturated polyester curing should not be combined with PB resin because the metal-catalyzed decomposition of peroxides creates gel specks in the mixer. The practical service temperature of cured PB-modified networks is limited to 120–150 °C in air for continuous use; above 150 °C, oxidative embrittlement reduces elongation at break by more than 50% after 500 h in forced-air aging per ASTM D573-04.
Storage stability is maintained by nitrogen blanketing and storage at or below 30 °C; viscosity drift under air at 40 °C can exceed 10% per month for high-vinyl grades. The product is classified as a hydrocarbon resin by most suppliers, but the low-molecular-weight fraction may require ventilation and protective gloves under EU 10/2011 food-contact migration testing where applicable. Compliance records should include REACH 1907/2006/EC registration, RoHS 2011/65/EU for electrical applications, and FDA 21 CFR 175.105 for adhesives. Published data for this specific configuration is limited for some niche uses, and batch-specific certificates of analysis should be considered the controlling specification for molecular weight distribution, viscosity, and 1,2-vinyl content.
