| HS Code | 845638 |
| Product | Rilsan Fine Powders T Black 7239 MAC PA11 |
| Material | Polyamide 11 (PA11) |
| Color | Black |
| Density | 1.05 g/cm³ |
| Melting Point | 186 °C |
| Water Absorption 24h | 1.2 % |
| Bulk Density | 0.55 g/cm³ |
| Shore D Hardness | 72 |
| Tensile Strength | 42 MPa |
| Elongation At Break | 260 % |
| Flexural Modulus | 1200 MPa |
| Vicat Softening Point | 165 °C |
| Chemical Resistance | Excellent resistance to hydrocarbons, salt water, and moisture |
As an accredited Arkema Rilsan Fine Powders T BLACK 7239 MAC PA11 factory, we enforce strict quality protocols—every batch undergoes rigorous testing to ensure consistent efficacy and safety standards.
| Packing | Supplied in 25 kg sealed bags, this black PA11 fine powder ensures safe handling and moisture protection. |
| Container Loading (20′ FCL) | 20′ FCL container loaded with 25 kg bags of Arkema Rilsan Fine Powders T BLACK 7239 MAC PA11, palletized and shrink-wrapped. |
| Shipping | Ship Arkema Rilsan Fine Powders T BLACK 7239 MAC PA11 as a non-hazardous polyamide powder. Pack in sealed, moisture-proof containers to prevent clumping. Store away from ignition sources and static electricity. Transport in dry, covered vehicles, avoiding extreme heat or humidity. Ensure proper labeling and clean, dust-free handling. |
| Storage | Store in a cool, dry area away from heat, sparks, and open flames. Keep the container tightly sealed to prevent moisture absorption. Avoid direct sunlight and dusty environments. Use proper grounding to prevent static discharge. Keep away from oxidizing agents and foodstuffs. Maintain good ventilation and control dust accumulation. |
| Shelf Life | Shelf life is typically 2 years from production date when stored unopened in a cool, dry place. |
Arkema Rilsan Fine Powders T BLACK 7239 MAC PA11 is deposited as a dry, solvent-free film on zinc-phosphated or zinc-iron steel seat-belt anchors, door-check armatures, cable guides, and stamped brackets in automotive metal-finishing lines. The substrate sequence consists of alkali degreasing at 55–65 °C, double rinse, iron or zinc phosphate conversion, deionized rinse at conductivity below 30 µS/cm, and oven drying at 110–130 °C for 8–12 min. After masking threaded features or press-fit bores, the powder is applied with a corona spray gun at −60 to −80 kV, a gun-to-substrate distance of 150–250 mm, and booth relative humidity below 55 %. The black pigmentation can lower powder resistivity relative to natural PA11; gun current is therefore trimmed to 10–20 µA to suppress back-ionization and pinholing when film build exceeds 180 µm. A fused film of 200–300 µm is obtained in a convection oven at 200–220 °C for 10–15 min. Metal surface temperature must exceed the PA11 melting endotherm at 186–190 °C under ISO 11357-3 but remain below 240 °C, above which oxidative degradation raises yellowness and reduces reverse-impact resistance. If the powder has been stored or transported above 60 % RH, pre-drying at 80 °C for 4 h in a desiccant dryer is required to prevent moisture-induced flow defects during fusion. Adhesion on grit-blasted steel is evaluated by cross-cut to ISO 2409; class 0–1 is typical when alkaline residues and silicone release agents are absent. Neutral salt-spray testing to ISO 9227:2017 of a scribed panel with zinc phosphate pretreatment often exceeds 1,000 h before creep from the scribe exceeds 2 mm; exact values are dependent on primer chemistry and edge geometry.
For steel wire goods—dishwasher baskets, retail display racks, storage cage panels, and laboratory drain trays—fluidized-bed deposition is controlled less by dwell time than by the specific heat capacity and mass of the substrate. The wire part is first degreased and shot-blasted to Sa 2½ under ISO 8501-1, then preheated in a forced-air oven at 260–320 °C. The heated part is immersed in the fluidized powder bed for 4–10 s; film thickness is governed by heat transfer from the metal into the powder, with thicker wire sections of 6–10 mm generating sufficient thermal energy for a 300–450 µm fused layer, while thin 3–4 mm wire may require a preheat temperature at the upper end of the range to reach 250 µm. After withdrawal, residual heat is used to flow out the film; parts with high thermal inertia may need a post-cure cycle of 190–210 °C for 3–5 min. Compressed air used to fluidize the powder is oil-free and dried to a pressure dew point of −20 °C or lower, per ISO 8573-1:2010 class 2.2.1, to avoid moisture-induced agglomerates. Process failure at welded intersections appears as pinholes because the weld bead acts as a heat sink; preheat profiles are therefore timed for the heaviest section, not the average section. The fused coating is evaluated with a high-voltage holiday detector set at 5–8 kV based on 250–400 µm thickness, and adhesion is checked by cross-cut to ISO 2409 and by a 1.0 J direct-impact test to ASTM D2794. Published data for this black powder on thin-gauge welded wire is limited; a rack-level process qualification with 20 consecutive parts is common to set preheat temperature and fluidization air velocity.
| Process variable | Corona electrostatic spray | Fluidized-bed dip |
|---|---|---|
| Substrate temperature at deposition | 20–30 °C | 260–320 °C |
| Typical fused film thickness | 150–300 µm | 250–450 µm |
| Fusion/post-cure window | 200–220 °C for 10–15 min | residual heat plus 190–210 °C for 3–5 min if required |
| Compressed air condition | oil-free, dew point below −20 °C | oil-free, dew point below −20 °C, fluidization air velocity set by bulk density |
| Critical failure mode | back-ionization pinholes at film above 180 µm | weld heat-sink pinholes and edge pull-back |
Water-immersion service demands a different deposition route for pump impellers, butterfly valve discs, grooved couplings, and filter housings operating at 10–50 °C in potable or industrial water. Cast iron and carbon steel substrates are degreased, blast-cleaned to Sa 2½ under ISO 8501-1, and coated with a liquid epoxy primer when service conditions exceed 5 years of immersion or when cathodic disbondment resistance is specified. The PA11 powder is then applied either by fluidized-bed dip after preheat at 270–300 °C or by electrostatic spray followed by fusion at 200–220 °C. A minimum dry film thickness of 350 µm on water-contacting surfaces is maintained to cover casting porosity and to provide a barrier layer where low molecular-weight corrosion products would otherwise lift the film. The base polymer absorbs less than 0.5 % water at equilibrium under ISO 62; dimensional swelling is therefore low, but glycol-based antifreeze or strong oxidizing agents can alter adhesion and should be qualified separately. For potable water contact, certification under NSF/ANSI 61 on the finished component is required because the black pigment package and primer must be evaluated in the final formulation. Long-term immersion testing at 50 °C for 1,000 h followed by adhesion to ISO 2409 is used to screen delamination; published failure thresholds for this grade under chloraminated water at 2–4 mg/L are limited. Hardness and wear are measured to ASTM D4060 with CS-17 wheels and a 1,000 g load; comparative abrasion loss should be determined on the actual cast substrate rather than on polished panels.
Because PA11 has a low dielectric constant relative to liquid epoxies and low water absorption, it is used as a powder-applied insulation on folded aluminium busbars, interconnects, and battery module enclosures where a continuous 250–400 µm layer must withstand direct-current high-potential testing. The busbar surface is degreased, brushed or lightly blasted, and preheated to 220–250 °C before electrostatic spray or dip; a fusion cycle of 210–230 °C for 5–10 min flows out the film. Dielectric strength is evaluated to IEC 60243-1 and is commonly specified at 20–25 kV/mm for a 300 µm film at 23 °C; the black carbon pigment can reduce short-term dielectric strength relative to natural PA11, so the dielectric acceptance value must be confirmed on the actual powder lot. Holiday detection is set at 3–5 kV DC to locate pinholes without causing surface flashover. Thermal cycling from −40 °C to 125 °C for 50 cycles is then used to detect cracking at busbar bends; a bend radius below 3 mm can produce stress cracks because the fused PA11 layer is stiff at low temperatures. Insulation resistance after 500 h at 85 °C and 85 % RH is measured to ASTM D257; published data for this black-pigmented grade under humid high-voltage load is limited, so end-use qualification is recommended before volume release.
| Requirement | Standard or code | Acceptance criterion used in release testing | Application trigger |
|---|---|---|---|
| Cross-cut adhesion | ISO 2409 | class 0–1 on blasted steel | all metal coating segments |
| Direct impact | ASTM D2794 | no cohesive failure at 1.0 J | wire goods, fasteners |
| Neutral salt spray | ISO 9227:2017 | ≥ 1,000 h with ≤ 2 mm scribe creep on phosphated steel | automotive, architectural, offshore |
| Water absorption | ISO 62 | ≤ 0.5 % at equilibrium | water contact |
| Dielectric strength | IEC 60243-1 | ≥ 20 kV/mm at 300 µm | electrical busbar |
| QUV weathering | ISO 4892-3 | ΔE ≤ 2 after 1,000 h to ASTM D2244 | architectural |
| Heavy metals screening | RoHS 2011/65/EU Annex II | Pb, Hg, Cd, Cr(VI) below thresholds | electronic/architectural parts |
| REACH SVHC status | REACH candidate list | no SVHC above 0.1 % per supplier declaration | all segments |
Architectural hinges, door handles, facade brackets, and exterior security equipment have historically used two-pack polyurethane or epoxy liquid topcoats applied at 50–100 µm. Replacement with heat-cured PA11 powder changes the corrosion-control strategy from a thin decorative film to a thick thermoplastic barrier. Cast aluminium, stainless steel, and mild steel parts are degreased, conversion-coated or blast-cleaned, and preheated to 250–300 °C for fluidized-bed dip or coated electrostatically and fused at 200–220 °C. The resulting 250–350 µm film is harder to scratch through than a 60 µm liquid topcoat and can bridge minor surface defects. Weathering resistance is assessed by ISO 4892-3 QUV for 1,000 h; carbon black pigmentation provides UV screening, and colour change is measured to ASTM D2244 with ΔE values typically below 2 after 1,000 h on a smooth panel. Condensation resistance is tested to ISO 6270-1 for 500 h; blisters or loss of adhesion on edges below a 0.5 mm radius are recorded because sharp architectural edging can draw coating away during melt flow. Failure modes on production lines include craters from silicone-based polishing pastes and thickness drop at inner corners; cleaning before coating must remove silicone using an appropriate solvent wipe, and sharp edges should be rounded to at least R0.5 mm. The absence of volatile organic compounds in the powder simplifies air permitting, but the high substrate preheat temperature is a boundary condition that excludes heat-sensitive aluminium alloys with temper loss above 230 °C. RoHS compliance is verified by XRF screening against 2011/65/EU Annex II, and REACH SVHC status is documented through the supplier declaration.
In offshore atmospheric exposure at C5-M severity, hex bolts, U-bolts, flanges, and cable tray hardware are coated with the black PA11 powder after zinc-rich priming or zinc flake basecoat is applied. The primer provides sacrificial corrosion protection at the thread roots where powder coverage is thinnest; the PA11 topcoat adds a continuous 300–450 µm barrier against chloride ingress. Coating is performed by preheating fasteners to 270–300 °C and dipping in a fluidized bed for 3–6 s, followed by a post-cure at 200–210 °C for 5 min to complete fusion. Threads are then chased or re-tapped because the thickness change alters the pitch diameter; nuts are coated as matched sets to avoid assembly interference. Neutral salt spray to ISO 9227:2017 on scribed panels, cyclic corrosion testing to ISO 12944-6:2018, and adhesion to ISO 2409 are used for release testing. The maximum service temperature for continuous load is bounded by the PA11 softening point; sustained contact with surfaces above 130 °C can allow creep of the coating under clamp load. Incompatibility with strong amine-based thread sealants should be checked because alkaline species can attack polyamide 11 at elevated temperature; polyolefin- or PTFE-based thread compounds are typically less aggressive. Published data for this specific black powder under offshore atmospheric exposure is limited, so a 12-month marine site exposure is recommended when replacing a qualified zinc-flake coating.
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Arkema Rilsan Fine Powders T BLACK 7239 MAC PA11 is a black-pigmented polyamide 11 powder supplied for electrostatic spray, tribostatic spray, and fluidised-bed deposition. The polymer backbone is synthesised from 11-aminoundecanoic acid derived from castor oil. The grade designation T BLACK 7239 MAC identifies the colourant state, product number, and Arkema fine-powder processing suffix. Because grade-specific technical data are often restricted to direct supply-chain documents, a procurement specification should require the supplier technical data sheet, particle-size certificate, and melt-flow certificate. Typical PA11 powder density is 1.03–1.05 g/cm³ by ISO 1183-1:2019, and the crystalline melting range is 183–187 °C by ISO 11357-3:2018. Melt volume-flow rate may be measured per ISO 1133-1:2022 at 235 °C with 2.16 kg, but powder-coating process control relies more heavily on particle-size distribution and moisture content than on melt flow.
The comparative selection benchmark for PA11 powder is typically PA12 for low moisture uptake and PA6/PA66 for hardness and cost. Polyamide 11 has a lower density than PA6 and PA66, and a lower saturation moisture uptake than PA6 or PA66. The longer methylene sequence between amide groups yields a melting range between PA12 and PA6. For coating operations this means PA11 requires a lower part preheat temperature than PA6 but is less subject to water plasticisation than PA6/PA66, which stabilises dielectric and mechanical properties across humidity cycling. PA11 is also derived from castor oil; renewable carbon content can be documented by ASTM D6866-21 or ISO 16620-2:2019. Table 1 gives property ranges for polyamide powder families.
| Property | PA11 | PA12 | PA6 | PA66 |
|---|---|---|---|---|
| Density, g/cm³ | 1.03–1.05 | 1.01–1.03 | 1.12–1.14 | 1.13–1.15 |
| Crystalline melting range, °C | 183–187 | 174–180 | 218–225 | 255–265 |
| Saturation moisture at 23 °C, % | 1.6–1.8 | 1.2–1.6 | 8.0–9.5 | 7.5–8.5 |
| Renewable carbon input | Castor oil-based | Route-dependent | Petrochemical | Petrochemical |
The PA11 values are typical of the Rilsan Fine Powders range rather than specific to T BLACK 7239 MAC; a lot-specific certificate should be used for specification acceptance.
Application of this powder can be performed by electrostatic spray in a multi-booth coating line or by fluidised-bed dip coating. In corona spray, the powder is charged by a high-voltage electrode and transported by compressed air; the part is grounded. The fluidising air must be clean, dry, and regulated, because moisture adsorbed on the powder surface shifts volume resistivity and reduces charge-to-mass ratio. Production-scale fluidised-bed dip lines typically preheat degreased and abrasive-blasted steel components to a metal temperature between 250 °C and 350 °C, immerse for 3–12 s, and post-fuse at 200–230 °C for 2–5 min. Thinner aluminium parts use the lower half of the preheat range while heavy steel sections require the upper half; the actual time depends on part thermal mass and target film thickness.
Substrate preparation determines the performance of any PA11 coating. On steel, grit blasting to Sa 2½ per ISO 8501-1:2007 and a surface profile of 75–100 µm is typical for fluidised-bed application. On aluminium, a conversion coating is used before preheating to limit filiform corrosion under the PA11 film. Oil, drawing compounds, and silicone residues act as adhesion poisons and can produce delamination after ISO 4624:2016 pull-off testing. A water-break-free surface is a minimum go/no-go test, but it does not quantify surface energy; surface energy can be measured by contact angle per ASTM D5946-17.
Polyamide 11 absorbs atmospheric moisture through the amide bond. If the powder is stored outside a sealed container in a coating shop where relative humidity exceeds 60%, the surface moisture content can rise sufficiently to reduce fluidisation and promote clumping in the hopper. Pre-drying is then required using a desiccant dryer with a dew point below −20 °C or a hot-air oven at 80–90 °C. Drying time is bed-depth dependent; a 25 mm tray in a vented oven may require 4–6 h, whereas a fluidised-bed dryer may reduce this to 1–2 h. Flow aids such as fumed silica or aluminium oxide are sometimes incorporated at low addition levels, but the T BLACK 7239 MAC grade already includes post-polymerisation additives; additional blending must not exceed the supplier-approved top-up level because excessive flow aid can lower collision charging and reduce film build. Powder moisture should be measured by Karl Fischer titration per ISO 15512:2019, with a target moisture content below 0.15% before spray.
The powder is produced by compounding PA11 with carbon black and stabilisers in a twin-screw extruder, then grinding and classifying. Particle-size distribution is measured by laser diffraction according to ISO 13320:2020. Rilsan Fine Powders are typically controlled in the range between 20 µm and 150 µm, with the fines fraction below 10 µm limited to avoid low fluidisation and the coarse fraction above 180 µm limited to control orange peel and transfer loss. Supplier certificates for Rilsan Fine Powders often state bulk density between 0.45 g/cm³ and 0.65 g/cm³ according to ISO 60:1999 or ASTM D1895-17. Black pigmentation in T BLACK 7239 MAC may modify the dielectric response of the powder because carbon black can act as a semiconductive filler, depending on loading and morphology. Powder volume resistivity should be determined by ASTM D257-14 or IEC 62631-3-1:2016 using a compressed powder cell; values below 10⁹ Ω·m can cause self-discharge and thin film build, while values above 10¹³ Ω·m can cause excessive back-ionisation in corona systems. Published data for this specific black grade is limited; resistivity, charge-to-mass ratio, and triboelectric series should be requested from the supplier.
If the coating line processes both sheet-metal brackets and machined shafts on the same hanger, the preheat profile cannot be identical. The preheat oven temperature is usually set above the required part metal temperature, but thermal lag is governed by section thickness, part weight, and loading density. Heavy steel sections above 10 mm can require the upper bound of the 250–350 °C preheat range to reach PA11 fusion temperature, while aluminium components above 6 mm may overshoot if the same recipe is used. A pyrometer or attached thermocouple is used to record part temperature immediately before immersion. In electrostatic spray, the residual heat of the part after preheating is generally lower, and multiple passes may be needed to achieve a film thickness of 250–500 µm; the first pass fuses to a tacky layer, and subsequent passes build thickness before final post-fusion. Process standards for polyamide powder coating include ISO 8130-1:2019 for particle-size determination by sieving and ISO 2178:2016 for non-magnetic film thickness measurement. Published data for this specific configuration is limited.
Fused PA11 coatings are evaluated for adhesion, flexibility, impact resistance, and abrasion. Adhesion failure on prepared steel surfaces is typically assessed by ISO 4624:2016 pull-off testing, where values for solvent-cleaned and grit-blasted substrates are commonly in the range of 10–20 MPa depending on film thickness and blast profile. Impact resistance is measured by ISO 6272-1:2011 or ASTM D2794-93(2019); a frequently referenced acceptance criterion for fluidised-bed PA11 is no visible cracking at 1.8 J reverse impact. Flexibility is checked by cylindrical mandrel bend per ISO 1519:2011; PA11 powder coatings show no crack at mandrel diameters of 3–6 mm for films near 250 µm. Abrasion resistance can be quantified by Taber wear testing per ISO 9352:2012 or ASTM D4060-19; the reported wear index depends on pigment loading and surface roughness, and no single value should be assigned to all black-pigmented grades.
Cooling rate after post-fusion controls the crystalline fraction and therefore the flexibility and internal stress of the coating. Rapid air cooling from the post-fusion temperature of 200–230 °C produces a smaller spherulite size and lower crystallinity than slow cooling in a filled oven, which increases flexibility and reduces edge shrinkage. Post-fusion temperature must remain below the oxidative degradation threshold of the carbon black-pigmented PA11; prolonged exposure above 250 °C can cause yellowing, molecular weight reduction, and loss of impact resistance. Thermal degradation is monitored by melt viscosity change or solution viscosity per ISO 307:2019. Batch-to-batch variation in crystalline nucleation is influenced by pigment dispersion and by the thermal history of the powder during extrusion and grinding prior to classification.
PA11 powder coatings are specified where corrosion protection, impact damage resistance, and low moisture permeability are required. The lower polar group density relative to PA6 reduces equilibrium water content and provides resistance to aliphatic hydrocarbons, oils, and aqueous salt solutions. In salt-spray testing per ISO 9227:2017, scribed panels with 250–500 µm coatings can be exposed for 1000 h or more without underfilm corrosion when blast profile and adhesion are correctly controlled; the result depends on thickness, edge coverage, and scribe width, not solely on the polymer. Under cathodic protection, adhesion can be evaluated by cathodic disbondment methods such as ISO 15711:2003 or ASTM G8-96(2019). PA11 is not a thermoset; it can creep under continuous load but is resistant to dilute acids and bases at ambient temperature. Immersion in strong acids, phenolic solvents, or high-temperature alcohols can cause swelling or dissolution and should be avoided.
Differences from other Rilsan fine powder grades arise from particle-size distribution, pigmentation, and additive package. A natural or white PA11 fine powder may exhibit different triboelectric charging than a carbon-black-containing grade because carbon black alters surface conductivity and charge relaxation. The T BLACK 7239 MAC designation therefore cannot be substituted into a natural-powder process without recalibrating the powder feed, charge settings, and film thickness targets. The MAC suffix is an application-series indicator and does not replace the particle-size distribution stated on the certificate. If a line has been using a natural Rilsan PA11 fine powder with a d50 near 100 µm, changing to the black grade may require adjustment of the venturi pump injection air and hopper fluidisation pressure to maintain transfer efficiency; published data for this specific configuration is limited.
Corona charging produces a high charge-to-mass ratio and is less sensitive to powder moisture, but it can generate free ions that cause back-ionisation at film builds above 150–200 µm. Tribostatic charging depends on friction between powder and a charging surface, usually polytetrafluoroethylene, and it can deposit into Faraday cage areas with less back-ionisation; however, it is more sensitive to the triboelectric series position of the black pigment and to powder humidity. For T BLACK 7239 MAC, the presence of carbon black may narrow the tribostatic charging window. On automatic reciprocator lines, corona guns are often operated at 60–80 kV and a gun-to-part distance of 150–250 mm; tribo guns require higher powder velocity and controlled humidity below 40% RH. Powder output is typically 100–250 g/min per gun on reciprocators, but the acceptable range depends on booth extraction and part geometry.
Regulatory status for a black-pigmented PA11 powder must be confirmed with the supplier because pigment and additive packages can alter food-contact and drinking-water status. Typical Rilsan PA11 grades may be supported by statements for REACH compliance under EC 1907/2006, RoHS Directive 2011/65/EU, and FDA 21 CFR 175.300 for resinous and polymeric coatings if the grade-specific formulation is approved. Table 2 lists typical standards and test methods relevant to qualification; inclusion of a standard does not imply that T BLACK 7239 MAC satisfies every criterion without lot-specific confirmation.
| Scope | Standard | Use |
|---|---|---|
| Density | ISO 1183-1:2019 | Material specification and charge-mass calculation |
| Melting behaviour | ISO 11357-3:2018 | Fusion window and preheat setting |
| Moisture content | ISO 15512:2019 | Pre-drying control |
| Particle-size distribution | ISO 13320:2020 | Fluidisation and transfer control |
| Film thickness | ISO 2178:2016 | Non-magnetic substrate verification |
| Adhesion | ISO 4624:2016 | Pull-off adhesion acceptance |
| Impact | ISO 6272-1:2011 | Rapid deformation resistance |
| Salt spray | ISO 9227:2017 | Scribed corrosion assessment |
