LG Chem ABS BP-361 is an acrylonitrile-butadiene-styrene terpolymer supplied in pellet form for extrusion blow-moulded hollow parts, coextruded profiles, and thick-walled technical components. The grade is characterized by a relatively low melt mass-flow rate and high melt strength, which are intended to control parison sag and wall-thickness uniformity in deep-draw blow moulding. The product is supplied with a certificate of analysis aligned to ISO 10350-1:2017 single-point data presentation and is classified by the manufacturer as a high-impact ABS resin. All property values stated in this document are nominal, derived from specimens conditioned at 23±2°C and 50±5% relative humidity under ISO 291:2019, and are not lot release limits unless specified in the lot-specific certificate.

Material identity, specification methods, and nominal property envelope

The nominal property set for LG Chem ABS BP-361 is generated from dry injection-moulded specimens. The data support preliminary part design, tooling decisions, and early process-window estimation, but they do not replace prototype validation on production equipment. Blow-moulded wall sections may exhibit orientation-dependent mechanical properties that differ from test plaque data, and published data for this specific configuration is limited.

The melt mass-flow rate value at 2.0 g/10 min positions BP-361 at the low-flow end of the general-purpose ABS spectrum. This characteristic is not an accident of residual solvent or low molecular weight alone; it results from a higher molecular weight distribution and a controlled polybutadiene rubber phase that increases elongational viscosity. The tensile and flexural values are consistent with a general-purpose ABS terpolymer with impact resistance retained at ambient temperature, but the notched impact value should be interpreted as a moulded plaque measurement, not as a guarantee for butt-welded or pinched-off blow-moulded sections.

Where BP-361 is distinguished from general-purpose injection grades is in its lower melt mass-flow rate and higher melt strength. A typical injection grade such as LG Chem HI-121H is specified at 11 g/10 min under ISO 1133-1:2022 at 220°C and 10 kg, which permits short injection cycles and thin-wall fill. BP-361 at 2.0 g/10 min exhibits greater parison sag resistance and is therefore preferred for extrusion blow moulding of large ducts, air inlets, and hollow structural panels. The trade-off is a narrower injection-moulding processing window for parts with flow length-to-wall thickness ratios above 150:1; published data for this specific configuration is limited. The low flow derives mainly from the molecular architecture and rubber-phase morphology of the resin, not from a plasticizer-type viscosity reduction.

How does BP-361 compare with injection-moulding ABS grades under sustained shear?

Under sustained shear in a single-screw extruder, BP-361 develops higher head pressure at equivalent screw speed than high-flow injection grades. This pressure differential becomes visible on production lines when processors first substitute BP-361 into tooling designed for a high-flow grade. On a 90 mm single-screw extruder with L/D 24:1 and a barrier screw, stable parison weight is typically maintained with head pressure between 14 MPa and 22 MPa. Below 14 MPa, homogenization can become insufficient, producing parison weight variation above 3% shot-to-shot. Above 22 MPa, frictional heat raises melt temperature beyond 230°C and accelerates thermal degradation of the styrene-acrylonitrile phase.

The recommended barrel temperature profile for continuous extrusion is 180/195/205/210/215°C, with the die head held at 215°C. Screw speed on a 90 mm extruder is commonly set in the range 15–35 min⁻¹. Melt temperature at die entry should not exceed 230°C. At shear rates around 100 s⁻¹, the die swell and parison pre-blow behavior should be determined per line because the die swell response is influenced not only by the resin but also by die geometry, land length, and melt temperature; published data for this specific configuration is limited.

For injection-moulding comparisons, BP-361 should not be specified for thin-wall components below 1.5 mm unless processing conditions include fast injection speed, high packing pressure, and adequate gate dimensions. The lower melt flow of BP-361 reduces the practical flow length and may increase internal stress in injection-moulded parts. High-flow grades remain preferable where weld lines, long flow paths, and rapid cycle time dominate part design.

Pre-drying is not optional for BP-361 in humid production environments. At 23°C and 60% RH, pellets left in uncovered hoppers absorb surface moisture and can reach 0.10 wt% within a shift. The recommended drying condition is 80–85°C for 2–4 h in a desiccant dryer with a feed-air dew point below −30°C. Hopper residence time should be adjusted to maintain inlet moisture below 0.10 wt%. Production experience indicates that regrind from sprues, tails, and failed parisons carries higher surface moisture and should be re-dried separately or blended at or below 20 wt% with virgin pellets. The use of undried regrind in extrusion blow moulding has been observed to create surface splay, micro-voids at pinch-off weld lines, and audible steam popping at the die exit.

When moisture in the feed exceeds 0.10 wt%, extrudate quality becomes time-dependent

Moisture-sourced defects are not limited to cosmetic surface splay. Water present in the melt can hydrolyze processing additives, reduce molecular weight through hydrolytic chain scission, and create internal porosity that lowers pinch-off weld strength. In blow moulding, these defects localize at the parting line and at sharp radii where the parison is compressed. The result is a measurable loss in notched impact at the weld zone, even when the bulk material still meets the nominal 30 kJ/m² value. The practical moisture limit for extrusion-grade ABS is therefore lower than the limit sometimes permitted for injection moulding.

Drying parameters for BP-361 on a production line should be verified by measuring moisture content with a Karl Fischer analyzer instead of relying solely on dryer air temperature. A dew point below −30°C is necessary but not sufficient if the hopper residence time is too short or if the dry air flow is poorly distributed. The dried resin should be conveyed in closed channels and protected from ambient humidity during transport to the feed throat. Regrind must not be loaded directly from a floor hopper into the machine without separate drying, because the surface area of regrind causes faster moisture uptake than virgin pellets.

For extrusion blow moulding on shuttle machines with accumulator head capacities in the range 10–25 L, the material is commonly processed at melt temperatures of 210–225°C. Blow pin temperature is kept between 50°C and 70°C to stabilize pinch-off weld formation and reduce sink marks at thick sections. When wall thickness exceeds 5 mm, cooling time becomes the cycle-limiting step, and a lower melt temperature within the recommended range can improve part release and dimensional stability.

Explicit limitations in REACH, RoHS, and UL94 documentation

Compliance documentation for LG Chem ABS BP-361 commonly references Regulation (EC) No 1907/2006 for REACH and Directive 2011/65/EU as amended by (EU) 2015/863 for RoHS. The grade is not inherently flame retardant and carries a UL 94 HB classification at 1.6 mm. No statement of conformity to FDA 21 CFR 177.1020 for food-contact use should be assumed unless explicitly detailed in the supplier’s regulatory letter. Compatibility with paints, adhesives, and solvent-based assembly systems must be verified by patch testing because ABS is susceptible to stress cracking in the presence of ketones, esters, and aromatic hydrocarbons. Continuous service temperature is generally limited to 80°C unless an application-specific thermal ageing test has been completed under ISO 4577:2019 or equivalent.

BP-361 is not recommended for direct contact with strong acids, strong bases, or high concentrations of organic solvents. In applications involving hydrocarbon-based grease or adhesive curing agents, evaluation of environmental stress cracking resistance should be performed using the supplier’s recommended test method. Additive packages that introduce high levels of amine-based heat stabilizers or zinc oxide should be avoided where maximum notched Izod retention is required, because these can affect rubber-phase stability and long-term impact performance. Published interaction data for BP-361 with amine-based additives is limited.

Candidate uses for BP-361 include automotive heater and air-conditioner ducts, load-floor panels, recreational vehicle covers, industrial housings, furniture shells, and other blow-moulded parts requiring wall thicknesses from 2.5 mm to 6.0 mm and draw ratios of 2:1 to 4:1. In coextruded structures, the material can function as a cap layer or substrate layer combined with a regrind core to maintain surface appearance while controlling raw-material cost. For sheet extrusion, roll-stack temperatures in the range 70–85°C are used to balance surface finish and cooling stress. The part design must account for the anisotropic shrinkage of blown sections, especially at the parting line and at the pinch-off seam, where orientation and residual stress are highest.