Drive Performance, Travel Light
Amid the industry shift toward lightweighting, decarbonization, and long service life, PBT (Polybutylene Terephthalate) is widely used in connectors, sensor housings, fan blades, and lighting structures thanks to its dimensional stability, electrical performance, and chemical resistance. Introducing epoxidized linseed oil (ELO) as an eco-friendly toughening and synergistic stabilizing additive delivers a higher-value, more reliable solution for PBT compound systems.
Why Choose Epoxidized Linseed Oil (ELO)?
- Bio-based and eco-friendly: Plant-derived, low VOC and low odor, phthalate-free; compliant with RoHS/REACH and OEM sustainability requirements.
- Reactive epoxy functionality: Multifunctional epoxy groups in ELO can react with PBT terminal carboxyl/hydroxyl groups or form physical compatibility, improving interfacial adhesion and slowing thermo-oxidative/hydrolytic degradation.
- Toughening and impact resistance: Boosts low-temperature impact while maintaining modulus, reducing brittle failure risk under engine bay temperature cycling and assembly impacts.
- Processing-friendly: Improves melt flow and lubrication, reduces shear heating and black speck formation, widens the molding window, and enhances part appearance and dimensional consistency.
- Flame retardant synergy: Compatible with halogen-free P/N systems, lowers dripping, densifies char; helps achieve UL 94 V-0/5VA targets.
Typical Automotive Use Cases
- Electrical connections and high-voltage components: Terminal housings, wire harness connectors, high-voltage orange parts
- Highlights: Stable dielectric strength, designable CTI ≥ 600 V, maintains volume resistivity after long-term heat aging.
- Thermal management and airflow: Fan blades, air doors, air guides
- Highlights: Balanced impact–stiffness, improved fatigue crack growth resistance, reduced low-temperature whistling and edge chipping.
- Lighting and radar brackets: Lamp body frames, sensor housings, radar mounts
- Highlights: Dimensional stability with low warpage; better resistance to stress cracking around self-tapping screws.
- Charging and e-drive peripherals: Charge port housings, DC/DC converter housings, cable clamps
- Highlights: Flame-retardant system compatibility, improved flow for stable filling of complex thin walls.
Performance Uplift Examples (Typical Formulation Window)
- Base: PBT or PBT/glass fiber (10–30% GF)
- ELO loading: 0.5–3.0 phr (parts per hundred resin), commonly 1–2 phr
- Observed improvements (vary by base resin, processing, and formulation):
- Notched impact at 23 ℃: +10–30%
- Low-temperature impact at −30 ℃: +15–40%
- Elongation retention after long-term heat aging: +10–25%
- Flow (MFR/screw torque): 5–15% improvement
- FR synergy (with P/N halogen-free): reduced dripping, more uniform char
Notes: Data reflect industry-verified reference ranges. Optimize with target resin, GF sizing, and FR system.
Processing and Manufacturing Notes
- Drying: PBT at 120 ℃ for 4–6 h; store ELO sealed and away from light to avoid moisture uptake and acid value increase.
- Compounding:
- Feed PBT at main hopper; side-feed ELO and FR/antioxidants.
- Melt temperature 235–255 ℃; control residence time to avoid overreaction and viscosity drift.
- Injection molding:
- Mold temperature 80–120 ℃; medium-to-high injection speed for appearance and weld-line strength.
- Watch mold-release levels to prevent surface tack from additive stacking with ELO.
- Stabilizer pairing: Combine with hindered phenol/phosphite AO, plus CaCO(_3) or talc to further enhance thermo-oxidative and dimensional stability.
- Compatibility: Compatible with common GF silane sizings; small amounts of compatibilizer (e.g., epoxy-grafted polyester) can fine-tune polarity.
Quality and Compliance
- Regulatory: Meets RoHS, REACH, ELV; SVHC and content declarations available.
- Automotive process: PPAP package support, IMDS entry, batch consistency control (acid value, epoxy value, color).
- Reliability validation:
- Thermal aging 150–180 ℃; damp heat 85 ℃/85% RH; salt spray; chemical media (ATF, brake fluid, coolant) compatibility.
- Electrical: CTI, RTI, resistivity.
- Mechanical: Multi-axial impact, screw/boss fatigue, weld-line strength, environmental stress cracking (ESC).
Deliverables
- Masterbatch option: ELO 10–30% in PBT carrier for stable dispersion and easy on-press adjustment.
- Ready compound: PBT/GF/FR/ELO integrated FR grades; UL files can be aligned.
- Customization: Formulation design for wall thickness, color (black/natural/high weatherability), CTI rating, and FR targets.
Value Summary
- Durable and reliable: Higher impact, better resistance to thermo-oxidation and hydrolysis, extended part life.
- Process efficiency: Easier filling, fewer defects, lower total manufacturing cost.
- Green compliance: Bio-based and low VOC, contributing to vehicle carbon footprint reduction.
Let PBT in automotive applications be not only strong and tough, but also longer-lasting and more sustainable. Contact us for trial formulations and processing sheets—material recommendations and pilot pellets can be delivered within two weeks.