Shanghai Jiyie ABS K35H is an acrylonitrile-butadiene-styrene terpolymer grade supplied as cylindrical pellets for injection moulding and limited profile extrusion. The K35H designation denotes a high-impact variant within the K-series, with a rubber-phase particle size distribution weighted toward the 0.4–1.0 µm band. Published single-point data specific to K35H is limited in public industrial repositories; therefore the following baseline values are quoted from the broader K-series family and reference compatibilized ABS grades. Density is 1.04–1.06 g/cm³ under ISO 1183-1:2019, melt volume-flow rate is 8–12 cm³/10 min at 220 °C/10 kg under ISO 1133-1:2022, tensile yield stress is 41–45 MPa at 50 mm/min under ISO 527-2/1A, flexural modulus is 1,900–2,200 MPa under ISO 178:2019, notched Charpy impact strength is 28–35 kJ/m² at 23 °C under ISO 179-1/1eA, and Vicat softening temperature VST/B50 is 102–106 °C under ISO 306:2022. The grade is positioned between general-purpose ABS with notched Charpy values below 18 kJ/m² and very-high-impact extrusion grades exceeding 40 kJ/m².

Formulation-level differentiation from standard ABS reflects a higher polybutadiene rubber content, estimated at 16–20 wt% based on composition-property correlations for the K-series. High-flow ABS grades for consumer electronics typically reduce rubber below 10 wt% to reach >25 cm³/10 min melt volume-flow rates, and the viscosity reduction is accompanied by sharper ductile-brittle transitions and lower energy absorption in thin ribs. K35H retains a co-continuous SAN matrix with acrylonitrile content near 20–24 wt%, which controls solvent resistance and thermal stability. In comparison with high-flow ABS, K35H increases notched Charpy impact by roughly 40–70% at 23 °C but requires more holding pressure and longer cooling time for ribs with nominal wall thickness above 2.5 mm.

What Separates K35H from Standard High-Flow ABS and PC/ABS Blends?

In material-selection trials for unpainted enclosure components, the difference between K35H and other products appears at the intersection of melt fluidity, impact retention, and paint-line thermal resistance. K35H does not compete with super-high-flow ABS grades in long thin-wall flow-length ratios above 150:1; those grades use lower rubber content and often include lubricants to reach MVR >30 cm³/10 min. K35H instead competes where impact loading on bosses and snap-fit features is the primary rejection mode. Compared with PC/ABS blends, K35H has lower heat deflection temperature and lower chemical resistance to aromatic solvents, but also lower melt viscosity and reduced drying severity. The table below gives representative comparative values obtained under the same test protocols.

The published data specific to K35H is limited, so the comparison is made against K-series family values and typical commercial reference grades. The difference in impact behavior is most visible at 0 °C and -20 °C; high-flow ABS often fails below 8 kJ/m² at -20 °C, while K35H generally retains a notched Charpy value above 10 kJ/m² if moulded with sufficient surface temperature. The limit of K35H appears at sub-zero service below -30 °C, where all standard ABS grades show a ductile-brittle transition unless rubber particle spacing is modified with special SAN-grafted core-shell impact modifiers.

When Moulders Replace 757-Type ABS with K35H in Thin-Wall Electronics Housings

The feasibility of substituting K35H into tools originally dimensioned for 757-type ABS depends on melt pressure requirement and cooling time. K35H exhibits lower melt flow than 757-type general-purpose ABS, so injection pressure at the transfer point typically rises by 8–15% in a 1.2 mm nominal wall tool with a flow-length ratio of 120:1. On a 1,800 kN hydraulic injection moulding machine with a 32 mm diameter screw and L/D 20, the observed barrel temperature profile is 210–230 °C from feed to nozzle, with nozzle temperature not exceeding 240 °C. Mould-wall temperature is held at 45–60 °C to maintain gloss uniformity and avoid jetting at the gate. The shot mass is kept between 40% and 70% of barrel capacity to limit residence time below 5 min; if the screw recovery time exceeds 20 s, the grade is likely too viscous for the tool and high-flow ABS should be considered.

Gate size is a frequently overlooked constraint. For K35H, tunnel or submarine gates below 0.8 mm diameter increase shear heating and can raise local melt temperature by 10–20 °C, which may lead to yellowing at the gate if the nozzle is already above 245 °C. Production-scale moulders typically enlarge the gate to 1.0–1.2 mm or use a fan gate to minimize shear-induced degradation. The grade can be used with hot-runner systems with external heating; internally heated hot runners are less suitable because stagnant zones can exceed 260 °C and accelerate degradation of the butadiene phase.

Thermal Degradation and Screw Recovery Limits in Heated Barrel Operations

The butadiene-rich phase in K35H is sensitive to thermal-oxidative degradation at barrel temperatures above 250 °C. At 250 °C with a 5 min residence time, discoloration and a measurable drop in notched Charpy impact are documented for similar high-impact ABS grades; therefore the barrel-temperature setpoint should not exceed 240 °C for cycles exceeding 60 s. The process window is bounded by the need to maintain melt temperature high enough for thin-wall filling and low enough to avoid rubber crosslinking or chain scission. Maximum shear rate at the gate should remain below 50,000 s⁻¹; above this limit, melt fracture and surface matting appear in high-impact ABS due to elastic instabilities.

Screw recovery characteristics are governed by the low compression ratio and high rubber content. K35H can be processed on general-purpose polyolefin screws with compression ratios of 2.5:1 to 3:1, but the metering zone should be at least 4–5 diameters long to homogenize the SAN phase. On a 2,000 kN servo-hydraulic press with a 35 mm screw, the plasticating capacity may drop by 10–15% relative to a high-flow ABS at the same back pressure of 5–8 MPa, because rubber particles increase melt elasticity and reduce forward conveying efficiency. Increasing back pressure above 8 MPa does not improve dispersion and may excessively extend recovery time.

Unpainted interior trims, vacuum cleaner housings, and power-tool casings are common production applications. K35H has sufficient weld-line strength for large flat parts with multi-gate layouts, but its higher melt viscosity relative to high-flow ABS can create visible weld lines if two flow fronts meet at melt temperature below 215 °C. Maintaining a mould temperature of at least 50 °C in the weld zone and using sequential valve gating reduce flow-front cooling, and improve weld-line impact to approximately 80% of the base material’s notched value. For parts with metal threaded inserts, the grade’s higher elongation and rubber content reduce cracking around insert bosses compared with general-purpose ABS, but insert preheating to 80–100 °C is still recommended to prevent residual stress concentration.

Sheet extrusion of K35H can be performed on single-screw extruders with a barrier screw design and barrel temperatures from 200–230 °C. The resulting sheet can be thermoformed, but sheet sag increases with rubber content; the grade is not recommended for deep draws with draw ratios above 0.7 unless a higher-viscosity extrusion ABS is selected. When coextruded with a cap layer for outdoor weatherability, K35H can serve as a substrate layer, while the cap layer should be ASA or PMMA-modified ABS to add UV stability.

Long-term UV exposure of uncoated K35H causes chalking and yellowing because the polybutadiene phase is prone to photo-oxidation. For outdoor applications, a coextruded ASA cap layer or UV-stabilized paint is required. Without UV protection, gloss retention and Charpy impact decrease after 12 months of outdoor exposure; published data for this specific configuration is limited, but comparable high-impact ABS grades show notched impact reductions of 30–50% after 2,000 h in xenon-arc weathering to ISO 4892-2.

Chemical resistance of K35H follows ABS behaviour: the SAN phase is attacked by ketones, esters, and chlorinated solvents, while the polybutadiene phase is swollen by mineral oils and aromatic hydrocarbons. The grade is not suitable for continuous contact with brake fluid, strong alkaline cleaners above pH 10, or concentrated acetic acid; in these environments stress cracking can initiate at weld lines and bosses. Painting and electroplating operations for K35H require the same surface activation as standard ABS, typically chromic acid etching for electroplating or adhesion promoters for two-coat polyurethane systems. K35H is not a flame-retardant grade. Where electrical enclosures require UL 94 V-0 at 1.5 mm, a flame-retardant ABS or PC/ABS blend must be specified. The standard K35H grade is expected to achieve UL 94 HB at 3.0 mm, conditional to the stabilizer package and pigment loading; chlorinated flame retardants are not used in the K-series base polymers.

Desiccant Drying at 80 °C Prevents Melt-Phase Splay in High-Humidity Production

ABS resins are hygroscopic enough that surface moisture causes splay and internal voids, but K35H does not require the severe drying cycle used for PC/ABS blends. The recommended desiccant-dryer settings are 80 °C for 2–4 h to reach residual moisture below 0.1% by mass. If the material is exposed to ambient air above 60% RH for more than 30 min, the hopper inlet dew point should be maintained below -30 °C; otherwise moisture uptake at the pellet surface increases and melt-phase hydrolysis can produce surface silver streaks. In a production environment with 70% RH and 25 °C, uncovered gaylord storage can add 0.15–0.25% moisture within 12 h, and the material must be re-dried before use.

Moisture regain after drying is also influenced by pellet temperature. If pellets discharged from a hot dryer exceed 50 °C, they cool rapidly in transfer lines and can reabsorb surface moisture. Therefore, insulated hoppers and short conveying distances are needed. In comparison with high-flow ABS, K35H with its higher rubber content can tolerate slightly higher residual moisture, but only for non-aesthetic parts; any application requiring electroplating or high-gloss appearance should maintain the 0.1% residual moisture limit.

Mould shrinkage for K35H is in the range 0.5–0.7% parallel to flow and 0.6–0.8% perpendicular, depending on wall thickness and mould temperature; higher mould temperature reduces post-mould shrinkage but increases cycle time. Post-mould shrinkage at 80 °C for 1 h may add 0.1–0.3%, so dimensional drawings should include a process capability study on the tool geometry. Batch-to-batch variation in melt volume-flow rate for K35H should be controlled through supplier certificate of analysis; a typical acceptance window is ±2 cm³/10 min at 220 °C/10 kg. On a production-scale injection line, variation beyond that will affect cushion position and injection pressure stability. The resin should be sampled at receiving and tested for MVR and moisture before use, because regrind addition beyond 20 wt% lowers impact and increases viscosity variation. Regrind should be dried and free of fines; if regrind levels exceed 20 wt%, notched Charpy impact at -20 °C may fall by 10–15% due to repeated shear history.

Under European and North American regulatory schemes, ABS is generally specified for industrial and consumer articles rather than direct food contact. K35H can be evaluated under REACH and RoHS for heavy metals and restricted substances, but any food-contact claim must be validated against specific migration limits for acrylonitrile, butadiene, and styrene. A compliance checklist for common global standards is provided below.

Without a supplier certificate of analysis for a specific lot, K35H cannot be assumed to meet food-contact or medical-grade requirements. The base polymer should be free of heavy-metal pigments and cadmium-based heat stabilizers; the exact stabilizer package is confidential to Shanghai Jiyie but should be disclosed as a compliance statement for regulated applications.