Romira ABS ROMILOY 1300 is an unfilled acrylonitrile-butadiene-styrene injection-moulding compound supplied by Romira GmbH. The model designation belongs to the ROMILOY 1300 series and identifies a medium-flow ABS grade. Manufacturer-reported melt volume-flow rate is 23 cm³/10 min when determined at 220 °C under 10 kg in accordance with ISO 1133-1:2022. Density is 1.04 g/cm³ under ISO 1183-1:2019. The material is supplied as cylindrical pellets for reciprocating-screw injection-moulding machines with a three-zone general-purpose screw, L/D ratio of 18:1 to 24:1, and compression ratio of 2.0:1 to 2.5:1. The grade is not intended for profile extrusion or blow moulding because melt strength is lower than extrusion-oriented ABS types.

Drying is mandatory before processing. The granules are dried in a desiccant dryer at 80 °C for 2–4 h, targeting residual moisture below 0.05%. If ambient relative humidity exceeds 60%, opened packaging is dried immediately before use. Inadequate drying produces splay, silver streaks, and reduced notched impact strength due to hydrolysis of the polybutadiene phase. Nozzle melt temperature is maintained between 220 °C and 260 °C. Mould temperature is held between 40 °C and 80 °C, with the upper range used for gloss-sensitive surfaces and the lower range for faster cycle times when dimensional tolerances permit.

The values in the table are reported typical data, not lot-release specification limits. Individual production lots may vary within the contracted tolerances agreed between the moulder and the compounder.

Rheological characterisation beyond the single-point MVR value is recommended for mould-filling simulation. Published capillary rheometry data for ROMILOY 1300 is limited; medium-flow ABS grades with MVR near 23 cm³/10 min typically shear-thin from approximately 900 Pa·s at 10 s⁻¹ to 100–150 Pa·s at 10³ s⁻¹ at 240 °C. Generic ABS Cross-WLF coefficients used in flow simulation may introduce fill-pressure errors above 15%, so material-specific coefficients should be obtained from the compounder before tool design sign-off.

What Distinguishes ROMILOY 1300 from Low-Flow ABS Extrusion Grades and PC/ABS Blends?

The MVR of 23 cm³/10 min positions ROMILOY 1300 in the medium-flow injection-moulding segment. Extrusion-oriented ABS grades are typically formulated below 10 cm³/10 min to maintain melt strength during sheet and profile take-off. The higher flow of ROMILOY 1300 reduces fill pressure in multi-cavity tools and permits shorter flow paths in thin-wall parts. However, melt strength is lower; hot-runner drool, nozzle stringing, and gate-stringing are more likely unless nozzle temperature is trimmed toward the lower half of the melt window and decompression is limited to 2–4 mm of screw retraction.

Compared with short-glass ABS injection grades, which exhibit tensile modulus above 5,000 MPa, ROMILOY 1300 is a lower-stiffness option with tensile modulus near 2,300 MPa. It is selected when load-bearing deflection is not the main design constraint. The absence of glass fibre reduces tool wear and improves surface appearance. Relative to PC/ABS blends with Vicat B50 above 110 °C and notched Charpy values above 40 kJ/m², the ABS grade has lower heat and impact capability. The selection boundary is normally set by heat deflection requirement, drying capacity, and chemical resistance, not by flow length alone.

Controlling Melt Residence Time and Gate Freeze in Reciprocating-Screw Machines

Processing on standard three-zone screws of 20:1 L/D requires nozzle temperature monitoring because shear heating can raise actual melt temperature above barrel set points. When shot weight is below 30% of barrel capacity, total residence time at 240 °C should not exceed 5 min; at 260 °C, residence time is reduced to 2–3 min. Longer residence produces brown streaks, increases melt viscosity, and lowers Charpy notched impact through thermal ageing of the rubber phase. Barrel temperatures are usually profiled from 210 °C at the feed zone to 230–250 °C at the metering zone and nozzle.

Gate freeze behaviour depends on gate thickness, mould temperature, and holding pressure. For an edge gate with land length 0.8 mm and thickness of 60% of wall stock, gate seal is normally reached in 3–6 s at 60 °C mould temperature. Premature switch-over to holding pressure before cavity fill is complete causes sink marks; excessive hold time increases residual stress and reduces environmental stress-crack resistance. Injection velocity is set by flow path thickness, with thin-wall applications often requiring 150–250 mm/s and cavity fill times below 0.8 s. Closed-loop process control with cavity-pressure transducers can maintain peak cavity pressure variation within ±5% in production batches.

Screw geometry with excessive compression or high-shear mixing can generate frictional heat and push melt temperature above 260 °C. A general-purpose screw with a compression ratio of 2.2:1 and no high-shear mixing section is preferred. Shut-off nozzles are used on machines with horizontal injection units to prevent drool. Back pressure is limited to 5–10 bar hydraulic because additional shear work reduces repeatability of shot size.

When Thin-Wall Electronic Enclosures Require UL 94 HB at Reduced Wall Thickness

ROMILOY 1300 is classified HB at 1.5 mm under UL 94. For wall thickness below 1.0 mm, published data for this specific configuration is limited, and part-level testing is necessary because ABS flammability depends on thickness, flow-induced orientation, and colorant loading. In thin sections, melt temperature near 250 °C and injection velocity of 150–250 mm/s are required to prevent short shots. These conditions increase the risk of material degradation when venting is inadequate, making vent depth and position critical.

Electronic enclosure tools frequently use cold-runner systems with full-round runners of 4–6 mm diameter to balance fill across multiple cavities. Edge gates are set at 50–70% of wall thickness, and vents are cut at last-fill locations with depth 0.02–0.03 mm. Mould temperature is maintained at 60 °C to balance sink marks and surface gloss. Because the grade is unfilled, differential shrinkage between flow and transverse directions is moderate, but mould shrinkage values of 0.4–0.6% require tolerance review on snap-fit ribs and bosses.

For a 1.2 mm wall thickness enclosure, the typical processing window has a melt temperature tolerance of ±5 °C. Below 245 °C, short shots may occur in the last-filled cavity; above 255 °C, surface splay and brown streaks become detectable. This narrow window is dependent on gate count and runner balance. Multi-cavity tools with 8–32 cavities require geometrically balanced runners and uniform cooling circuits because melt temperature variation above ±5 °C changes fill time and gate freeze, producing cavity-to-cavity mass variation.

Chemical compatibility follows general ABS behaviour. Contact with ketones, esters, aromatic hydrocarbons, or plasticiser-containing PVC gaskets can induce environmental stress cracking. Components exposed to cleaning agents or sunscreen should be evaluated under ISO 22088-2:2006 or ASTM D543-21 using moulded parts, not test bars, because moulded-in stress dominates failure. Continuous contact with hot water above 60 °C is not recommended for unstabilised ABS because hydrolysis of the butadiene phase reduces impact. Published data for ROMILOY 1300 under continuous chemical exposure is limited; generic ABS data should not be extrapolated to stress-crack-sensitive geometries without part-level validation.

Regulatory position is established at the lot level. The compounder normally provides confirmation that the grade meets the substance restrictions in the RoHS Directive 2011/65/EU and the registration requirements of REACH Regulation (EC) No 1907/2006. No food-contact statement is attached to the standard grade unless a lot-specific compliance letter is issued. The material is not inherently UV-stabilised; outdoor components require an additional weathering package or substitution with an ASA or PC/ASA grade when colour shift and gloss retention are critical.

Thermal Stability and Regrind Use Demand Separate Acceptable-Quality Limits

Regrind can be incorporated at 20–30% by weight when the regrind is dry and free of contamination. Higher regrind fractions reduce notched impact and increase the incidence of black specks. The regrind should be processed through the same drying procedure as virgin material. Repeated heat history on three or more moulding cycles shifts the rubber phase toward crosslinking, lowers MVR to approximately 18–20 cm³/10 min, and increases yellowness index. Because ABS degradation is not linear, regrind use should be validated by measuring Charpy notched impact under ISO 179-1:2010 and visual inspection under DIN 6174 or equivalent colourimetric criteria.

Thermal ageing of moulded parts is not governed solely by Vicat softening. Continuous use above 80 °C may cause oxidative embrittlement of the polybutadiene phase, depending on part mass and air access. Short-term excursions to 95 °C in non-load-bearing locations are tolerated, but the heat deflection temperature under 1.8 MPa is 98 °C, so load-bearing parts should have a safety margin against HDT. For underhood or high-ambient applications, a heat-resistant ABS or PC/ABS grade is required when peak service temperature exceeds 85 °C.

In automotive interior retainers and clips, ROMILOY 1300 is selected over glass-filled ABS when dimensional tolerance and surface appearance outweigh modulus. The unfilled system reduces tool wear in high-cavitation tools. Process monitoring on production lines has used cavity-pressure sensors with short-shot limits set at 95% of peak pressure to maintain pack variation within ±0.5% of part mass. Screw recovery time is kept below cooling time to avoid cycle-time increases from the medium-flow melt viscosity. Mould temperature variation across cavities should be held within ±3 °C to prevent differential shrinkage and warpage in long, thin features.

For appliance control-panel housings with textured surfaces, the mould temperature is raised to 70–80 °C to replicate texture and reduce visible weld lines. General ABS weld-line data indicate that a weld line formed at 30° can retain approximately 70% of the unfilled tensile strength, while a head-on weld line may retain less than 50%. ROMILOY 1300-specific weld-line values should be confirmed on the moulded part before gate positions are fixed in tool steel.