Lihuayi Lijin Petrochemical ABS M347 is an acrylonitrile-butadiene-styrene terpolymer supplied as pellets for injection moulding. The material is a heterogeneous polymer system in which a grafted polybutadiene rubber phase is dispersed within a continuous styrene-acrylonitrile copolymer matrix. The base polymer is covered by CAS Registry Number 9003-56-9; additives, colourants, and processing aids vary with production lot and must be declared on the lot-specific safety data sheet. The grade designation M347 identifies an injection-moulding balance in which melt fluidity, notched impact resistance, and surface reproduction are adjusted for thin-wall and medium-wall parts. Because the polybutadiene content, graft efficiency, and molecular weight distribution are specific to the M series, the material should not be substituted for high-gloss, high-heat, flame-retardant, or electroplating ABS grades without a tool trial. Lot-specific physical and mechanical data, including melt volume-flow rate, tensile properties, and Izod impact, must be taken from the current producer certificate of analysis rather than from class-typical literature.

What distinguishes M347 from high-impact and high-heat ABS grades in the same moulding family?

The primary difference lies in the polybutadiene particle-size distribution and the degree of grafting. High-impact extrusion ABS grades are typically controlled to a coarser rubber particle population and may show notched Izod values above 30 kJ/m² at 23 °C, but the higher rubber content lowers melt flow and can produce a duller surface. M347 is specified where the threat of brittle failure is moderate and the manufacturing cost driver is injection speed or multi-cavity fill. Heat-resistant grades achieve Vicat B50 values of 105–120 °C by replacing part of the styrene with α-methylstyrene or by adding maleimide-based comonomers; this raises the required melt temperature and can contribute to brown discolouration during hot-runner hold time. M347 retains a conventional SAN continuous phase, so its Vicat softening temperature generally lies in the 90–105 °C class-typical band rather than in the high-heat band.

Electroplating grades differ again: they use a tailored rubber morphology and a higher butadiene content to maximize adhesion of electroless nickel or copper after chromic acid etching, whereas M347 is not specifically marketed as an electroplating compound. Flame-retardant grades contain halogen or phosphorus packages and are rated V-0 at 1.5 mm; M347 should be assumed to be a general-purpose HB-class material unless the exact grade carries a yellow card that states otherwise. Extrusion grades for sheet or profile applications may show melt volume-flow rates below 10 cm³/10 min at 220 °C/10 kg, while high-flow thin-wall moulding grades may exceed 30 cm³/10 min. M347 occupies the middle range, which makes it suitable for balanced part design. This placement does not imply that the exact M347 value is 20 cm³/10 min; it must be confirmed with the current batch certificate.

Processors running Lihuayi Lijin Petrochemical ABS M347 on production lines should pre-dry pellets to a residual moisture content below 0.10% by weight. A desiccant-bed dryer set at 80–90 °C for 2–4 h is typical; at ambient relative humidity above 60%, hopper loading should be closed-loop and drying time extended. Wet resin causes splay, silver streaks, and a measurable loss of notched impact strength, because steam expansion at the gate and hydrolysis reactions can degrade the polybutadiene phase. The melt temperature measured at the nozzle is maintained between 220 °C and 250 °C. Sustained melt temperatures above 260 °C or residence times longer than 15 min produce oxidative yellowing and black specks from degraded rubber. A general-purpose screw with 20:1 L/D and compression ratio 2.5:1–3.0:1 is preferred; high-shear barrier screws should be evaluated for temperature rise because ABS is pseudoplastic and can overheat at high screw speed.

Mould temperature influences gloss, knit-line strength, and dimensional stability. A coolant temperature of 40–80 °C is used for textured and semi-gloss surfaces; lower settings reduce cycle time but increase moulded-in stress and can produce low-temperature brittle failure at weld lines. Cavity pressure monitoring is recommended for multi-cavity tools because changes in gate freeze time and packing pressure of as little as 5–10% can shift part mass and shrink dimension. On production lines with clamp forces from 800 kN to 4500 kN, the screw cushion is typically maintained at 3–8 mm to ensure consistent packing. If the cushion collapses or transfer is not monitored, shot-to-shot variation in melt density can produce dimensional drift in ABS flow paths. Regrind from sprues and rejected parts may be incorporated at 20–30% by weight when the production lot has been validated, but repeated heat history increases the crosslink density of the rubber phase and reduces notched Izod values.

Electronic device enclosures, small household appliance housings, vacuum cleaner bodies, router casings, and consumer electronics frames are among the components for which a medium-flow ABS such as M347 is specified. These applications typically require wall thicknesses of 1.2–2.5 mm, moderate drop-impact resistance, and sufficient gloss or texture reproduction. At wall thickness below 1.0 mm, moulders should use the producer’s spiral-flow curve or viscosity data for Moldflow simulation; published data for this specific configuration is limited, and tool trials are necessary. For parts requiring dimensional stability under load, the tensile and flexural creep behaviour of unreinforced ABS should be assessed under ISO 899-1 or ASTM D2990. M347 is not recommended as a direct replacement for UV-stable ASA or AES in outdoor enclosures because the polybutadiene phase undergoes photo-oxidation and chalk if unpainted or unprotected.

The melt rheology of M347 is shear-thinning. Capillary rheometry under ISO 11443 can be used to derive viscosity coefficients for simulation. At shear rates typical of injection moulding, 100–1000 s⁻¹, apparent viscosity falls by an order of magnitude relative to low-shear values. This allows filling of thin sections at moderate injection pressures, but it also means that hot-runner systems must have balanced channels and no dead spots. Residence time in the hot runner should be minimized to prevent gel formation from the polybutadiene phase. Mould shrinkage for general-purpose ABS typically lies between 0.4% and 0.7%, depending on wall thickness, gate design, packing pressure, and flow orientation.

When M347 replaces painted ABS or die-cast metal in load-bearing housings, creep, chemical resistance, and thermal ageing define the design window

Designing with M347 as a substitute for painted ABS interior trim or zinc/aluminium die-cast housings requires a different failure-mode analysis. Unreinforced ABS has a lower modulus than glass-filled engineering polymers and exhibits time-dependent strain under continuous load; ISO 899-1 creep data should be used for snap-fit beams and screw bosses. Solvent exposure from plasticizers, esters, ketones, or aromatic hydrocarbons can cause crazing and stress cracking in the SAN phase, particularly at knit lines or injection gate regions. The material should not be placed in contact with strong bases or concentrated oxidizing acids. Thermal ageing above 70 °C in air accelerates oxidation of the polybutadiene rubber, leading to loss of toughness and yellowing; intermittent exposure at 80–90 °C may be acceptable only after heat-ageing tests on finished parts. Painted grades require adhesion testing according to ISO 2409 or ASTM D3359, and mould-release agents must be eliminated or fully removed before paint or adhesive bonding.

Chemical resistance and regulatory documentation remain batch-dependent

Compliance statements for Lihuayi Lijin Petrochemical ABS M347 cannot be transferred from one production line to another without review. Under REACH Regulation (EC) No 1907/2006, the polymer itself may be exempt from registration, but monomers and additives above the reportable limits must be identified in the extended safety data sheet. The RoHS recast Directive 2011/65/EU limits cadmium to 0.01% by weight and lead, mercury, hexavalent chromium, PBBs, and PBDEs to 0.10% by weight in homogeneous materials; the resin supplier must provide a conformity declaration for each lot or grade. Food-contact status under FDA 21 CFR 180.22 or Commission Regulation (EU) No 10/2011 depends on the exact additive package, colourants, and processing aids, and cannot be assumed from the general-purpose ABS base polymer. For electrical enclosures, flammability classification under UL 94 is grade- and thickness-specific; an HB rating is common for general-purpose ABS, but the yellow card for the exact M347 grade must be retrieved from the UL database.