Mocom ALCOLOR SAN A YL5036-15 is a yellow colour concentrate based on a styrene-acrylonitrile copolymer carrier intended for melt incorporation into SAN, ABS, and related styrenic copolymers. The designation ALCOLOR SAN A identifies the carrier chemistry rather than a universal wax or polyolefin system; YL5036 defines the yellow colour space; -15 is a manufacturer recipe index and does not itself specify pigment loading. Public technical documentation for this exact grade does not provide a fixed generic specification. Processors should request the lot-specific certificate of analysis for pigment content, ash residue, melt volume-flow rate, and residual moisture. The SAN carrier is selected where close refractive-index compatibility with transparent or translucent SAN is required. Because the carrier and the matrix share an amorphous styrenic backbone, the masterbatch can disperse as a compatible phase rather than a discrete low-molecular-weight phase, reducing light scattering and weld-line haze compared with EVA- or wax-borne colour concentrates. The same carrier chemistry, however, introduces hygroscopic behaviour and requires desiccant drying before processing.

Which drying and feeding limits apply when the concentrate is processed on conventional injection moulding lines?

Because the carrier is hygroscopic, ambient moisture uptake must be controlled. For SAN-based colour concentrates, desiccant drying at 80 °C for 2–4 h to a residual moisture below 0.1 wt% is common when relative humidity exceeds 60 %. Drying air should have a dew point of −30 °C or lower. Insufficient drying of ALCOLOR SAN A YL5036-15 can produce silver streaking, splay, and surface cratering at the melt front; hydrolytic chain scission of the SAN carrier may also reduce melt viscosity and shift final colour coordinates. Hopper residence time at drying temperature should not exceed 4 h unless the system continuously discharges pellets and monitors dew point. Prolonged heating of concentrated organic yellow preparations can cause pellet bridging or surface stickiness. For first-lot validation, water content should be measured by Karl Fischer titration according to ISO 15512:2019. At the feed throat, gravimetric dosing is preferred over volumetric dosing when let-down ratios below 2 wt% are required because pellet size variation and auger pulsation introduce short-term colour changes. The concentrate should be introduced with the natural SAN stream to avoid prolonged residence time in the rear barrel zone.

On a reciprocating-screw injection moulding machine with screw diameter between 25 mm and 40 mm, the product is typically introduced after the first barrel zone. Processing on machines with clamp force below 500 kN becomes sensitive when shot size is below 20 % of barrel capacity; short residence time may leave unmelted pigment agglomerates near the gate. Melt temperature should be measured by air-shot pyrometry and maintained between 220 °C and 250 °C for standard SAN grades, and between 230 °C and 260 °C for high-flow ABS mixtures. These ranges are general for SAN-based yellow concentrates; the natural resin supplier’s melt window and the pigment’s thermal stability remain the controlling limits. Back pressure between 5 bar and 10 bar is usually sufficient to homogenise the concentrate without excessive shear heating. Back pressure above 15 bar can raise melt temperature by 5–10 °C and accelerate yellow-pigment degradation. Screw rotation speed for screw diameters above 30 mm should be limited to 60–100 min⁻¹. Decompression should not exceed 3 mm in short-shot moulding; excessive decompression pulls air into the melt and produces gate splay. Published lot-specific injection data for YL5036-15 is limited, so production parameters should be confirmed by design of experiments on the production tool.

Injection Moulding Conditions, Screw Recovery, and Short-Shot Behaviour

The screw L/D ratio should be at least 20:1. Short screws below 18:1 may fail to disperse the concentrated pigment unless a mixing section is present. Colour consistency in thin-wall SAN parts is sensitive to the interaction between screw recovery time and cooling time. When recovery time is shorter than cooling time by more than 2–3 s, melt residence time in the barrel is extended and the pigment can be exposed to thermal stress. Conversely, when recovery time is too long, cycle time increases without improving dispersion. Barrel temperature profiles should be flat or slightly reverse; the front zone should not exceed the melt temperature by more than 10 °C. For hot-runner systems, each nozzle should be independently controlled, and shut-off nozzles should be used in idle cavities to prevent decomposition of the yellow pigment. If the system has a melt filter, a screen pack of 40–60 mesh is common for masterbatch processing; finer screens increase back pressure and may shear-heat the SAN carrier. The geometry of the check ring and the decompression stroke should be evaluated when colour streaks appear despite adequate back pressure. Published data for this specific product in hot-runner configurations is limited.

The main difference between ALCOLOR SAN A YL5036-15 and universal wax- or EVA-borne yellow concentrates is the fate of the carrier phase in the final SAN melt. Universal carriers form a separate low-molecular-weight phase that can scatter light at thin sections, gate marks, and weld lines. The SAN carrier in this product is chemically similar to the matrix, so the risk of visible phase separation is lower. Compared with liquid colour systems, solid SAN-based pellets release less volatile organic material during processing but have a larger minimum dosing increment and require longer purging sequences during colour changeovers. Compared with ABS-based colour concentrates, the SAN carrier does not contribute polybutadiene; this is beneficial for transparency and chemical resistance, but it does not add impact modification to high-impact ABS. When the product is diluted into ABS, impact performance is therefore controlled entirely by the matrix resin. Users who need food-contact status must not assume that the model code alone provides regulatory approval. The final article must be tested against Regulation (EC) No 1935/2004 or FDA 21 CFR relevant sections. Published regulatory data for YL5036-15 is limited and must be requested from the supplier.

When the product is used on a co-rotating twin-screw extruder for pre-colouring or compounding, the screw should provide sufficient dispersive mixing without excessive shear. Kneading blocks with 30° or 45° forward angles are typical for colour concentrates; reverse elements increase residence time but may overheat the SAN carrier. Over-dispersion of yellow pigment can reduce opacity in opaque systems and shift shade, while under-dispersion produces visible specks. The extruder L/D ratio should be at least 28:1 for single-pass masterbatch let-down when the output rate exceeds 50 kg/h. If the line operates near its torque limit, the concentrate should be added by side feeder to avoid prolonged residence time. Published data for this specific product in twin-screw compounding is limited; scale-up from laboratory batches should include melt temperature monitoring at the die.

When the let-down ratio exceeds 4 wt% in glass-filled SAN, what property conflicts appear?

At addition levels above 4 wt%, the colour concentrate begins to occupy a measurable volume fraction of the matrix. Because the masterbatch carrier is unfilled, adding it to a glass-filled SAN compound dilutes the glass content of the final part. In a compound with 20 wt% glass fibre, a 4 wt% addition of colour concentrate reduces the effective glass content by approximately 0.8 wt%, assuming the pigment preparation is non-reinforcing. This dilution is measurable in flexural modulus and heat deflection temperature when tested according to ISO 178:2019 and ISO 75-2:2013. High yellow pigment loadings in glass-filled SAN can also increase weld-line visibility because fibres and pigment particles orient differently at the converging flow front. For critical load-bearing parts, the let-down should be reduced to the minimum needed to achieve the target L*a*b* coordinates under D65/10° illumination. If the required colour strength still exceeds 4 wt%, a custom pre-coloured glass-filled SAN compound may be more appropriate than a masterbatch dilution. Published data for this exact grade in glass-filled systems is limited.

Thermal Stability and Pigment Degradation Windows in the YL5036-15 Carrier System

The processing window of the product is bounded by carrier degradation at high temperatures and incomplete melting at low temperatures. SAN copolymers can undergo chain scission and release styrene and acrylonitrile at temperatures above 280 °C, although visible yellowing may begin earlier. Organic yellow pigments vary widely in thermal resistance; benzimidazolone and isoindolinone yellows can tolerate short residence times up to 300 °C, while some diarylide yellows decompose near 200 °C. Because the exact pigment chemistry of YL5036-15 is not publicly specified, processors must obtain thermal stability data from the certificate of analysis or conduct a melt-held study at the intended processing temperature for 5–10 min in an inert atmosphere. Heat history in a blocked hot-runner system can exceed 10 min, which is sufficient to degrade a heat-sensitive yellow pigment even if the bulk melt temperature remains within the recommended range. Furthermore, oxygen in the melt can accelerate colour shift; barrel zones should be designed to avoid air entrapment, and the hopper should be purged with dry air or nitrogen when ambient humidity exceeds 70 %.

Colour development should be controlled by spectrophotometric data rather than visual inspection alone. The CIE 1976 L*a*b* coordinates of the final part should be measured with a sphere or 45°/0° spectrophotometer under D65/10° conditions in accordance with ISO 11664-4:2008. Haze and total luminous transmittance of transparent tinted SAN can be measured according to ASTM D1003-21. For opaque or glass-filled parts, colour difference tolerances are better expressed as ΔEab* and Δb* values; a Δb* shift of +0.5 is visible in pale yellow tints, while a Δa* shift of −0.5 can shift the shade toward green under D65. When press-plaque comparison is used for incoming inspection, plaque thickness must be fixed because colour strength is thickness-dependent in translucent applications. A 2 mm injection-moulded plaque is common for colour acceptance, but thin-wall parts below 1 mm require separate standards. Published data on thickness-dependent colour strength for this specific product is limited.

The product must be evaluated for end-use compliance before production. For electrical and electronic equipment, the formulation may need to satisfy RoHS Directive 2011/65/EU Annex II restrictions for lead, cadmium, mercury, hexavalent chromium, and brominated flame retardants; the SAN carrier itself is not halogenated but the pigment packaging may contain restricted substances. For toys, migration of certain elements from the final article must meet EN 71-3:2019+A1:2021 or applicable national legislation. For food-contact applications, the final plastic article must comply with Regulation (EC) No 1935/2004 and relevant national measures such as FDA 21 CFR parts. The use of a SAN carrier does not by itself provide food-contact approval. If the colour index of the yellow pigment is not disclosed, processors should treat the product as industrial and request a full regulatory declaration. Published compliance data for Mocom ALCOLOR SAN A YL5036-15 is limited and should be confirmed with the manufacturer for each batch.

Outdoor exposure of yellow SAN components coloured with YL5036-15 should be tested because SAN itself has limited UV resistance unless the final matrix contains an appropriate stabiliser package. Lightfastness of the yellow pigment can be evaluated according to ISO 4892-2:2013 with xenon-arc exposure, but the carrier’s UV degradation will influence surface gloss, colour stability, and chalking behaviour. Without a UV stabiliser system in the final SAN matrix, yellow parts can exhibit colour fade and surface chalking even when the pigment itself has acceptable lightfastness. For exterior applications, the processor should consider ASA or another weatherable styrenic matrix; melt compatibility and lightfastness of YL5036-15 in ASA should be confirmed by testing. Published data for this specific grade in ASA weathering applications is limited.