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Evonik VESTAMID® Care ML21 Medical Grade Nylon 12

    • Product Name: Evonik VESTAMID® Care ML21 Medical Grade Nylon 12
    • Factroy Site: Yudu County, Ganzhou, Jiangxi, China
    • Price Inquiry: admin@ascent-chem.com
    • Manufacturer: Ascent Petrochem Holdings Co., Limited
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    Specifications
    HS Code 316164
    Density 1.01 g/cm³
    Melting Point Dsc 178 °C
    Glass Transition Temperature Dry 40 °C
    Heat Deflection Temperature 1 80 Mpa 50 °C
    Vicat Softening Temperature B 50 140 °C
    Tensile Modulus 1 Mm Min 1400 MPa
    Tensile Stress At Yield 50 Mm Min 40 MPa
    Tensile Strain At Yield 5 %
    Elongation At Break >200 %
    Charpy Notched Impact Strength 23 C 10 kJ/m²
    Water Absorption 24 H 23 C 50 Rh 0.1 %
    Water Absorption At Saturation 50 Rh 0.7 %

    As an accredited Evonik VESTAMID® Care ML21 Medical Grade Nylon 12 factory, we enforce strict quality protocols—every batch undergoes rigorous testing to ensure consistent efficacy and safety standards.

    Packing & Storage
    Packing Supplied as 25 kg sealed polyethylene-lined bags in cardboard boxes, ensuring dry, contamination-free delivery of Evonik VESTAMID® Care ML21 medical grade nylon 12.
    Container Loading (20′ FCL) 20′ FCL: medical-grade nylon 12 pellets packed in sealed, moisture-proof bags on pallets, ensuring safe, clean transport.
    Shipping This medical-grade nylon 12 resin ships in sealed, moisture-proof packaging to preserve purity and prevent contamination. Store in a cool, dry area, avoiding direct sunlight and extreme temperatures. Handle with clean equipment to maintain its sterile profile. Standard lead times apply; ensure dry conditions during transport and warehousing.
    Storage Store VESTAMID® Care ML21 in its original, sealed packaging in a cool, dry area away from direct sunlight and moisture. Keep the environment well-ventilated and avoid temperatures above 25°C. Protect from humidity and contact with oxidizing agents. Properly stored, the medical-grade nylon retains its properties for its intended shelf life.
    Shelf Life Shelf life is typically 3 years from manufacture date when stored in original, unopened packaging under cool, dry conditions.
    Application of Evonik VESTAMID® Care ML21 Medical Grade Nylon 12

    Single-screw extrusion of catheter shaft tubing from VESTAMID® Care ML21 begins with desiccant dryers operating at a dew point below -40 °C. Pellets are held at 80–90 °C for 4–8 h to bring residual moisture below 0.10 %, measured by Karl Fischer titration per ISO 15512:2019. The extrusion line typically uses a 20–25 mm screw with an L/D ratio of 24:1–30:1 and a compression ratio of 2.5:1–3.0:1. Barrel zones are set from 200 °C at the feed throat to 230 °C in the metering section, with the die head maintained at 210–230 °C. Tubing enters a vacuum sizing tank with water at 15–25 °C and is pulled at a draw-down ratio between 1.05:1 and 1.15:1 to limit frozen-in orientation. Multi-lumen catheter profiles with wall sections from 0.15 mm to 0.40 mm require closed-loop diameter gauges capable of holding ±0.03 mm tolerance. Coextrusion of a VESTAMID® Care ML21 outer layer over an HDPE or PTFE inner liner uses a spiral mandrel die and a second extruder running at 200–220 °C; layer interfaces must remain above 210 °C to prevent delamination. When radiopacity is specified, a BaSO₄-filled PA12 masterbatch is let down at 10–20 % by weight. Published let-down data specific to ML21 with barium sulfate is limited, so dispersion and opacity must be verified by X-ray imaging and a biological evaluation plan under ISO 10993-1:2018, clause 4. Post-extrusion annealing at 120–140 °C for 1–2 h stabilizes crystallinity and reduces later shrinkage during flaring, tip forming, and solvent-assisted bonding.

    ParameterSingle-screw tube extrusionInjection molding
    Pre-drying temperature80–90 °C80–90 °C
    Pre-drying time4–8 h4–6 h
    Residual moisture limit<0.10 %<0.10 %
    Melt temperature200–230 °C220–240 °C
    Die or mold temperature210–230 °C40–80 °C
    Screw L/D ratio24:1–30:120:1–25:1
    Draw-down or flow shrinkage1.05:1–1.15:10.8–1.2 % flow per ISO 294-4:2018

    How Does Gate Freeze Time Influence Shrinkage in Thin-Wall Drug Delivery Device Housings?

    Injection molding of autoinjector housings and inhaler actuator bodies from VESTAMID® Care ML21 is governed by gate freeze time because wall thickness is typically 0.8–1.5 mm, producing flow length-to-wall ratios that can exceed 120:1. The polymer is dried to below 0.10 % moisture and then processed with a melt temperature of 220–240 °C and a mold temperature of 40–80 °C. Gate freeze time is approximated by the square of gate thickness divided by thermal diffusivity; for PA12, a gate diameter of 0.8–1.0 mm on a valve-gated hot runner freezes in 0.5–1.5 s, after which hold pressure no longer compensates volumetric shrinkage. Shrinkage anisotropy is verified on plaques per ISO 294-4:2018, with flow-direction values of 0.8–1.2 % and transverse values of 0.7–1.1 %. When a color masterbatch is added at 1–2 wt%, pigment particles can nucleate crystallization and shift the solidification plateau, so dimensional capability must be re-qualified after each masterbatch lot change. Molding is performed on a two-platen injection molding machine with clamp force from 500 kN to 1000 kN, using cavity pressure sensors to transfer from velocity to pressure control at 400–600 bar. Ejection is postponed below the glass transition region to reduce distortion of snap-fit retention features. Biocompatibility documentation for the finished device assembly follows ISO 10993-5:2009 and ISO 10993-10:2021, with systemic toxicity evaluation per ISO 10993-11:2017 and USP <87>, <88> Class VI testing where the device contacts body fluids or mucosal tissue. Manufacturing controls are maintained under ISO 13485:2016, clause 7.5.1, and design transfer is documented to FDA 21 CFR Part 820.30.

    When respiratory therapy tubing is converted from VESTAMID® Care ML21, the outer diameter is typically 4–12 mm and wall thickness ranges from 0.8 mm to 1.5 mm. A single-screw extruder with an L/D of 24:1–30:1 feeds a vacuum calibration tank with water at 20–30 °C, while an external bead corrugator with mold blocks at 20–30 °C forms the finished profile. Because PA12 absorbs less moisture than PA6 or PA66 at 50 % relative humidity, the extrudate retains better dimensional stability in humidified patient circuits, but pre-drying is still performed at 80–90 °C for 4–8 h. If opacity is required, a white TiO₂ masterbatch is added at 2–4 wt%; published data for this specific ML21 configuration is limited, and dispersion should be verified by microscopy and pressure decay testing. The finished corrugated or smooth-bore tubing is tested under ISO 18562-1:2017 for particulate emissions and ISO 18562-2:2017 for volatile organic compounds when the gas pathway is within the breathing circuit. Dimensional compatibility with patient interface connectors is verified to ISO 5356-1:2015 for conical connectors. Flexural fatigue of corrugated sections is assessed by repeated bending over a mandrel at 23 ± 2 °C and 50 ± 5 % relative humidity, with acceptance criteria derived from the device risk management file under ISO 14971:2019.

    When Autoclavable Handles Are Overmolded onto Stainless Steel Instruments

    For surgical instrument handles overmolded with VESTAMID® Care ML21, the stainless steel insert is preheated to 120–150 °C before being placed into the mold cavity. The mold is maintained at 60–80 °C to slow solidification and improve mechanical interlock. Because unfilled PA12 does not chemically bond to stainless steel without an adhesion promoter, the insert should have a knurled or undercut retention zone with surface roughness Ra of 1.6–3.2 µm. Processing is typically performed on a vertical injection molding machine with a reciprocating screw and a rotary table, allowing insert loading and part extraction outside the clamp area. Melt temperature is held at 230–240 °C, and injection pressure is limited to 600–900 bar to avoid flaring the insert seating face. Cycle time for a handle with a shot weight below 20 g is 20–35 s, including cooling time of 8–15 s. After molding, parts are annealed at 120–140 °C for 1–2 h to reduce residual stress before repeated steam sterilization at 134 °C for 3 min under ISO 17665-1:2006. Moisture uptake during autoclaving can cause slight dimensional expansion, so handle-to-shaft clearance must be verified after a full sterilization cycle. Biocompatibility is assessed via ISO 10993-5:2009 and ISO 10993-10:2021, and steam sterilization validation is supported by ISO 11138-3:2017 biological indicator testing.

    Laser Transmission Welding Parameters for Microfluidic Manifold Plates

    Microfluidic manifold plates and diagnostic cartridge housings are assembled from two VESTAMID® Care ML21 halves by laser transmission welding. The upper component is natural or lightly pigmented to maximize laser transmission, while the lower component contains a laser absorber, typically carbon black at 0.05–0.2 wt% or a low-visible absorber such as Clearweld at 0.1–0.3 wt%. A fiber laser operating at 980 nm with a spot diameter of 1.5–3.0 mm is directed through the upper layer and absorbed at the interface. Typical welding parameters include laser power of 30–80 W, scan speed of 10–50 mm/s, and clamping pressure of 0.5–2.0 N/mm². Weld penetration depth of 0.2–0.6 mm is confirmed by cross-section microscopy, and burst pressure of the bonded manifold is tested by pressure decay per the device risk file. Published data for ML21-specific laser welding parameters is limited, so the stated ranges should be qualified on the production fixture because pigment loading, moisture content, and surface finish shift absorption. Residual moisture above 0.10 % generates steam at the interface and produces voids visible as weld-line porosity. The assembled cartridge is evaluated for cytotoxicity per ISO 10993-5:2009, and manufacturing process validation is conducted under ISO 13485:2016, clause 7.5.2.

    Two-shot overmolding of Luer-activated valves and soft-touch syringe grips uses VESTAMID® Care ML21 as the second shot over a rigid polycarbonate or ABS core. The rigid substrate is molded first and then transferred at 80–100 °C to the second cavity, where ML21 is injected at 230–240 °C. The interface temperature must exceed 140 °C to create a melt bond, but the sealing taper cannot be placed near a weld line because ISO 80369-7:2016 requires dimensional and liquid leakage performance on the Luer cone. Flash at the taper is controlled below 0.05 mm by precision parting-line shutoffs and a mold temperature of 40–60 °C. Cooling time for the second shot is 8–15 s, and total cycle time for a 10–20 g part is 25–40 s. The soft-touch overmold is unfilled, so mechanical interlock is required on the rigid core; a macro-texture depth of 0.2–0.5 mm on non-sealing surfaces improves peel resistance. Sterilization compatibility for ML21 components may be validated under ISO 11135:2014 for ethylene oxide or ISO 11137-2:2013 for gamma radiation, with absorbed dose typically not exceeding 25 kGy. Published data for repeated gamma exposure of this specific grade is limited, so material aging after the maximum specified sterilization dose must be verified under the device stability protocol.

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    Certification & Compliance
    More Introduction

    Evonik VESTAMID® Care ML21 is an unfilled, plasticizer-free polyamide 12 medical-grade resin supplied in cylindrical pellet form. The grade is specified with a density of 1.01 g/cm³ under ISO 1183-1, a differential scanning calorimetry melting endotherm near 178°C under ISO 11357-3, and a melt volume-flow rate on the order of 9 cm³/10 min at 230°C with a 2.16 kg load under ISO 1133-1. The viscosity number determined under ISO 307 is approximately 210 ml/g, placing ML21 in an intermediate-flow position within the VESTAMID Care PA 12 portfolio. This melt viscosity supports both thin-wall injection molding of connectors, clips, and hubs and precision extrusion of catheter tubing. The longer aliphatic repeat unit in PA 12 yields lower density and lower equilibrium water absorption than PA 6 or PA 66. At saturation in 23°C water under ISO 62, the typical water uptake is approximately 1.5 wt%, whereas published values for PA 66 commonly reach 8–9 wt%. The lower moisture uptake reduces the dry-as-molded versus conditioned modulus shift, a factor that directly affects the dimensional stability of fluid-handling components.

    The absence of a deliberate plasticizer is relevant for drug-contact applications because it removes one source of low-molecular-mass migration into surrounding media. This compositional constraint, however, establishes a mechanical boundary: the elongation and low-temperature flexibility of ML21 are lower than those of formulated plasticized PA 12 grades. Component designers should treat the grade as a structurally robust, low-water-uptake polyamide rather than as a soft elastomer. The resin is intended for short-term and repeated-use medical devices; it is not positioned as a load-bearing permanent implant material. Final suitability for any particular clinical contact duration must be established through the device manufacturer’s biological evaluation report, not inferred solely from resin-supplier documentation.

    What distinguishes VESTAMID® Care ML21 from general-purpose PA 12 extrusion resins used in industrial tubing?

    The primary distinction lies in the controlled formulation and the supporting documentation package rather than in a different polymer backbone. General-purpose PA 12 grades may contain release agents, lubricants, or stabilizers that are not selected for body-contact applications. ML21 is supplied under a medical-grade change-management system with lot-to-lot documentation, restricted raw-material sources, and biocompatibility test data on representative specimens. Melt viscosity is tightly specified by ISO 307 and ISO 1133-1, which enables repeatable wall-thickness control in thin catheter shafts below 0.5 mm. In contrast, commodity PA 12 extrusion resins often have broader viscosity ranges because their principal applications do not require tight annular tolerances.

    Compared with glass-fiber-reinforced PA 12 grades, ML21 contains no glass fiber. Its tensile modulus is therefore below 2,000 MPa, and nominal strain at break remains above 50% under ISO 527-1/-2. This favors flexural fatigue resistance in tubing and snap-fit geometries, but it excludes applications requiring bearing-grade stiffness or creep resistance under sustained load. The following comparative table places ML21 alongside typical unfilled PA 66 and PA 6 values to clarify the material-selection trade-off.

    PropertyTest methodVESTAMID® Care ML21 typicalUnfilled PA 66 typicalUnfilled PA 6 typical
    DensityISO 1183-11.01 g/cm³1.14 g/cm³1.13 g/cm³
    Water absorption, saturation, 23°CISO 621.5 wt%8–9 wt%9–10 wt%
    Melting temperatureISO 11357-3178°C262°C220°C
    Tensile modulus, dry-as-moldedISO 527-1/-21,550 MPa3,000 MPa2,800 MPa
    Nominal strain at breakISO 527-1/-2>50%20–40%>50%

    Within the VESTAMID Care family, ML21 is differentiated from lower-viscosity grades such as ML16 and higher-viscosity grades such as ML24 by its melt volume-flow rate and viscosity number. The exact current specification limits for each grade are published in Evonik product datasheets and should be used for final grade selection rather than relying on single-point typical values.

    Mechanical evaluation of dry-as-molded specimens provides the following typical values from supplier documentation. These values are not design allowables and do not replace ISO 527-based tensile testing or ISO 179-based impact testing on conditioned, sterilized, or aged components.

    PropertyTest methodTypical value
    Density, 23°CISO 1183-11.01 g/cm³
    Melting temperature, DSCISO 11357-3178°C
    Tensile modulusISO 527-1/-21,550 MPa
    Tensile stress at yieldISO 527-1/-246 MPa
    Tensile strain at yieldISO 527-1/-25%
    Nominal strain at breakISO 527-1/-2>50%
    Charpy notched impact strength, 23°CISO 179-1/1eA6 kJ/m²
    Charpy notched impact strength, -30°CISO 179-1/1eA5 kJ/m²
    Shore D hardnessISO 86872
    Water absorption, saturation, 23°CISO 621.5 wt%
    Equilibrium moisture uptake, 50% RH, 23°CISO 620.7 wt%
    Melt volume-flow rate, 230°C/2.16 kgISO 1133-19 cm³/10 min
    Viscosity numberISO 307210 ml/g

    Moisture conditioning changes the mechanical response of PA 12 even though the absolute uptake is lower than that of PA 6 or PA 66. At 50% relative humidity and 23°C, equilibrium moisture uptake of approximately 0.7 wt% plasticizes the amide-rich amorphous regions, lowering tensile modulus and increasing impact toughness. Snap-fit calculations should therefore use conditioned values when the device is packaged in a humid environment or stored for more than 48 h after molding. Dry-as-molded data overestimate stiffness and underestimate impact toughness under clinical storage conditions.

    Processing window, moisture limits, and screw configuration for extrusion-grade PA 12

    Pre-drying is mandatory before melt processing. Pellets should be dried in a desiccant dryer at 80°C for 4–12 h to a residual moisture content below 0.1 wt%, measured by Karl Fischer titration under ISO 15512. Drying temperatures above 90°C should be avoided for extended periods because surface oxidation can produce yellowing and generate die-lip deposits. In central dry-air systems, hopper residence time should match throughput so that dried pellets are not held at temperature for more than 12 h without additional moisture protection.

    Extrusion of ML21 is typically performed on single-screw extruders with screw L/D ratios from 25:1 to 30:1. A three-zone screw with a compression ratio of 2.5:1 to 3:1 is standard. Barrel temperatures from feed zone to die are commonly set between 200°C and 230°C, with a melt temperature of 220°C to 245°C. Melt temperatures above 260°C increase the risk of thermo-oxidative degradation, gel formation, and deposition on die lips. On medical tubing lines with wall thicknesses between 0.25 mm and 0.50 mm, draw-down ratios of 2:1 to 4:1 and water bath temperatures of 20–40°C are often used. Published data for this specific configuration is limited; line conditions should be verified by rheological characterization and dimensional capability studies on the intended production extruder.

    Injection molding of ML21 uses barrel temperatures of 230–250°C and mold temperatures of 40–80°C. Lower mold temperatures reduce cycle time but decrease crystallinity and may increase post-molding shrinkage variation. Higher mold temperatures near 80°C promote dimensional stability in components that will be sterilized. Hold pressure, cooling time, and screw-recovery profile should be established from cavity-pressure instrumentation rather than from generic molding tables, especially for thin-wall hub sections below 1 mm where flow hesitation can create weld-line weakness.

    Sterilization compatibility is not a single-value property. Ethylene oxide sterilization according to ISO 11135:2014 is commonly applied to PA 12 components; after processing, residual ethylene oxide must be controlled below the limits established in ISO 10993-7:2008. Gamma sterilization according to ISO 11137 can be applied at typical device doses of 25 kGy, but unfilled PA 12 may undergo discoloration and a shift in molecular weight distribution depending on dose rate, oxygen exposure, and antioxidant content. Steam sterilization at 121°C or 134°C per ISO 17665 is possible only if the part geometry tolerates moisture absorption and if the finished-device validation covers the required number of cycles. Repeated steam exposure can promote hydrolytic chain scission in the amorphous regions and should be evaluated with tensile or burst testing after worst-case cycling.

    Supplier documentation for VESTAMID® Care ML21 indicates testing for cytotoxicity under ISO 10993-5, irritation and skin sensitization under ISO 10993-10, acute systemic toxicity under ISO 10993-11, and hemolysis under ISO 10993-4. USP Class VI testing under USP <88> is cited in the VESTAMID Care grade documentation. These data support material screening but do not constitute regulatory clearance for a specific device. Device manufacturers remain responsible for the biological evaluation program required by ISO 10993-1:2018 and for compliance with relevant quality-system regulations such as FDA 21 CFR Part 820. Supplier documentation also indicates compliance with EU RoHS Directive 2011/65/EU and REACH Regulation (EC) No 1907/2006, with no substance of very high concern declared above 0.1 wt%.

    When devices are exposed to lipid emulsions, disinfectants, or repeated hospital cleaning agents, compatibility data must address environmental stress cracking

    Unfilled PA 12 offers lower equilibrium water absorption than PA 6 and PA 66, but it is not universally resistant to polar solvents, strong acids, or oxidizing agents. Immersion in 70% ethanol or 2% glutaraldehyde at 23°C may induce surface swelling or stress cracking in highly oriented thin sections. Environmental stress cracking should be evaluated using ISO 22088-3 bent-strip specimens if the clinical use includes repeated wiping with quaternary ammonium compounds, alcohols, or enzymatic cleaners. Published data for this specific configuration is limited; chemical compatibility must be validated on molded prototypes under worst-case clinical exposure rather than inferred from unstressed immersion plaques.

    Components molded from ML21 should not be exposed to concentrated nitric or sulfuric acid. Chlorinated solvents can swell the amorphous regions and should be avoided in manufacturing cleaning steps. If adhesive bonding is required, plasma or corona surface treatment is typical for PA 12, and bond performance should be confirmed by lap-shear testing under ISO 4587 or a device-specific tensile pull test. Additives containing amine-based adhesion promoters may interact with the polyamide backbone and should be checked for long-term hydrolytic stability before specification.

    The operational boundary for this material is defined by its semicrystalline morphology and its moisture sensitivity. Processes that over-dry or over-heat the melt reduce molecular weight and shift the property profile away from the supplier’s typical values. Processes that quench the melt too rapidly depress crystallinity and may alter shrinkage, while processes that anneal at 120–140°C for 2–4 h can increase crystallinity and dimensional stability but may reduce impact toughness. The correct thermal history depends on the dominant failure mode in the finished device, and no single processing condition applies to all catheter, connector, or surgical-instrument geometries.

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