Clariant white polycarbonate 3D printer filament is an amorphous, unfilled thermoplastic strand supplied for material extrusion platforms operating under the terminology of ISO/ASTM 52900. The product is based on bisphenol A polycarbonate, generic CAS registry 25037-45-0, and is pigmented with an inorganic white colorant system that provides opacity before printing and after post-processing. Spooled formats are nominally 1.75 mm or 2.85 mm diameter, with industrial lots normally inspected to a diameter tolerance of ±0.05 mm and ovality of ≤0.03 mm. The material is selected when service temperature, stiffness, and toughness requirements exceed the capabilities of PETG, PLA, or ABS. Because this is an unfilled polycarbonate rather than a compounded flame-retarded or carbon-fiber-reinforced grade, the processing window is dominated by moisture control, chamber temperature, and the need for a stable glass transition state during cooling. The exact Clariant grade code, production date, and lot-specific certificate of analysis on the spool label remain the authoritative source for compliance and property data.

The spool is generally supplied in a sealed polymer barrier bag containing a desiccant sachet and a humidity indicator card. Upon receipt, the package should be inspected for puncture; a breached moisture barrier invalidates the dry state and requires drying before processing. Unopened spools stored below 30 °C and 50 % RH retain their packed moisture level, but once opened the filament begins to equilibrate with ambient humidity. At 23 °C and 50 % RH, unfilled polycarbonate reaches an equilibrium moisture content of 0.12–0.20 wt% according to ISO 62. At relative humidity above 60 %, open-spool exposure longer than 4 h is sufficient to raise moisture above the safe extrusion threshold in many industrial environments. The material should therefore be returned to a desiccant chamber or dried before the next build cycle.

What Drying and Extrusion Limits Govern White Polycarbonate Filament?

Drying is the controlling operation. Residual moisture must be below 0.020 wt% before the polymer enters the hot end; above this boundary, heterogeneous hydrolysis at melt temperature generates bubbles, reduces interlayer fusion, and produces brittle or silvered side surfaces. Desiccant drying at 80–100 °C for 4–8 h with a dew point below -40 °C is the standard industrial method. Convection ovens may be used only with forced air and a vented spool support, because localized conduction to a solid tray can soften the hub or expand the wound core unevenly. Verification is performed with a moisture analyzer or coulometric Karl Fischer titration on a sacrificial length of filament. After drying, the spool is transferred to a sealed dry box maintained below 10 % RH and fed through a PTFE or reverse-Bowden tube to limit moisture re-entry.

Extrusion parameters are machine-specific but fall within a narrow band. The hot end must be all-metal and capable of sustained operation at 270–300 °C; white pigmentation may require the upper part of this range because titanium dioxide raises melt viscosity and reduces visible melt transparency. Nozzle diameters from 0.4 mm to 0.6 mm are appropriate, with layer heights of 0.15–0.25 mm for a 0.4 mm nozzle. The platen is held at 90–110 °C, and a chamber temperature of 60–80 °C is recommended for parts with long continuous perimeters. On open-frame machines without a chamber, warpage is controlled by reducing part size, using a brim of 8–15 mm, and preventing draft currents. First-layer speeds are limited to 20–30 mm/s, while outer perimeters can be printed at 30–60 mm/s. Direct-drive retraction of 0.5–1.5 mm at 20–40 mm/s or Bowden retraction of 4–6 mm at 30–50 mm/s prevents stringing without introducing extrusion stalls. Melt residence should be minimized: at 300 °C, a static hot end above 5 min causes molecular weight loss and local yellowing of the white pigment. If the machine is idle, the nozzle is purged with fresh polycarbonate before resuming the build.

Build plate surface selection is a process conflict. Float glass without an interlayer is insufficient at bed temperatures above 90 °C because adhesion develops only when the polycarbonate wets a high-energy polymer surface; PEI sheets, polyimide tape, or polycarbonate adhesive films are preferred. A fixed polycarbonate sheet can be used when the platen is cleaned with anhydrous isopropanol and maintained at 100–110 °C. If first-layer corners peel during the first 5 mm of build height, the thermal gradient at the bottom of the part is too high; corrections are to raise the chamber temperature, reduce the first-layer extrusion width below 120 % of nozzle diameter, or enclose the machine to limit convective loss.

White PC is sensitive to cross-contamination from lower-temperature thermoplastics. Residual PLA or PETG in the hot end can degrade at PC processing temperatures and form carbonaceous inclusions; a purge sequence with natural PC or a commercial purge compound at 270–300 °C is required before building white parts. The white pigment also makes contamination visible as dark specks, so the feed path from dry box to extruder should be sealed and free of abraded polymer dust.

Tensile, Thermal, and Flow Property Benchmarks

Table 1 lists class-typical values for unfilled white polycarbonate under standardized test protocols. Values are not lot-specific and must be superseded by the Clariant certificate of analysis for the exact grade. Published data for this specific configuration is limited, particularly for printed XY properties, because raster build orientation, air gap, and chamber thermal history produce different mechanical outcomes than injection-moulded test specimens.

Application temperature limits follow the heat deflection and Vicat data. Unreinforced white PC is appropriate for internal housings and fixtures exposed to transient temperatures up to 115 °C, but continuous service above 120 °C is not recommended because creep and dimensional relaxation accelerate near the glass transition. The material should not be used with strong alkalis, ammonia-based cleaning agents, esters, ketones, chlorinated solvents, or aromatic hydrocarbons under stress. Polycarbonate is susceptible to environmental stress cracking; ISO 22088-2 and ISO 22088-3 test methods are relevant when specifying parts for chemical exposure. If a printed part contains internal stress from differential cooling, annealing at 100–110 °C for 1–2 h may reduce cracking in service, but dimensional change during annealing must be compensated in the part design.

In electrical enclosures, the primary advantage over polyamide is lower moisture uptake and better dimensional stability in humidity swings up to 50 % RH. The comparative tracking index of any specific white PC is grade-dependent; before specifying for live parts, the data sheet’s CTI, dielectric strength, and UL 94 rating must be reviewed. Unmodified polycarbonate is not automatically flame-retarded, and the white unfilled product should not be assumed to satisfy V-0 requirements unless a yellow card or IEC 60695-11-10 classification is cited for that exact grade. Flame-retarded polycarbonate variants from Clariant, where applicable, differ from this unfilled white product by the addition of flame-retardant packages that can reduce impact strength and narrow the processing temperature window.

When Unfilled White PC Is Selected Over PC-ABS and PETG

Selection against PETG is driven by heat resistance and stiffness. PETG typically exhibits a heat deflection temperature of 64–70 °C at 1.8 MPa and lower flexural modulus, whereas the unfilled white PC values in Table 1 are approximately 60–70 % higher for flexural stiffness and nearly double the HDT/A. PETG prints with lower chamber requirements and less warp, but it is not a substitute when the part will be held at 100–115 °C during use.

Selection against PC-ABS is driven by rigidity and maximum service temperature. PC-ABS blends show better flow, reduced warp, and less printing difficulty in large thin-walled sections, but tensile yield and HDT/A are typically lower than unfilled polycarbonate. The trade boundary occurs at parts with wall thickness below 2.5 mm and build volumes above 200 mm; these favor PC-ABS for dimensional control, while thick-section heated fixtures favor white PC.

Selection against glass- or carbon-filled polycarbonate is based on ductility and surface finish. Filled grades offer lower thermal expansion and can reduce warpage, but they are abrasive, often require hardened nozzles, and produce lower elongation at break. Unfilled white PC retains higher printed ductility and is not abrasive to standard brass nozzles. Conversely, it has higher shrinkage and cannot be expected to match the dimensional accuracy of filled PC on large flat parts.

Shrinkage of unfilled PC after cooling from melt is anisotropic in fused filament fabrication. The coefficient of linear thermal expansion is 65–70 × 10⁻⁶ K⁻¹ per ISO 11359-2; if the part cools from 140 °C to 25 °C, an isotropic linear strain of approximately 0.7–0.8 % can be generated. In printed parts, the strain is constrained by the platen adhesion and layer deposition path, so it appears as curl, corner lift, or interlayer residual stress rather than uniform shrinkage. Dimensional compensation factors of 0.3–0.5 % in the X and Y planes and 0.2–0.4 % in the Z plane are sometimes applied to CAD data for close-fitting parts, but the actual values depend on chamber temperature and raster angle. Published data for this specific configuration is limited; dimensional qualification should be performed on a test coupon before committing a full build.

Compliance status for a white unfilled polycarbonate filament is not a single certificate; it is a matrix of substance, article, and application-specific requirements. Table 2 summarizes the standards that should be requested from the supplier or evaluated on the printed article.

In a production run for a white polycarbonate electrical enclosure, the spool is dried for 6 h at 90 °C, loaded into a dry box, and printed on a PEI-laminated platen at 105 °C with a chamber at 70 °C. The toolpath uses a 0.4 mm nozzle, 0.20 mm layer height, outer perimeter speed of 40 mm/s, and a brim of 10 mm. After removal, the part is annealed at 105 °C for 1 h and allowed to cool in still air. Threaded brass inserts are installed with a controlled-temperature soldering tip, and pre-tension is avoided at sharp boss edges to prevent stress cracking. This build sequence addresses the two dominant failure modes: hydrolysis from residual moisture and warpage-induced corner lift.