| HS Code | 622366 |
| Density | 1.02 g/cm³ |
| Melting Point | 170 °C |
| Tensile Modulus | 500 MPa |
| Tensile Strength | 42 MPa |
| Elongation At Break | 300 % |
| Shore Hardness | D 55 |
| Water Absorption At Saturation | 1.0 % |
| Glass Transition Temperature | -30 °C |
| Vicat Softening Temperature | 80 °C |
| Charpy Impact Strength 23 C Notched | 25 kJ/m² |
As an accredited Evonik VESTAMID® Care ML18 Medical Grade Nylon 12 factory, we enforce strict quality protocols—every batch undergoes rigorous testing to ensure consistent efficacy and safety standards.
| Packing | Evonik VESTAMID® Care ML18 is packaged in 25 kg sealed polyethylene-lined bags inside sturdy cardboard boxes, ensuring purity and moisture protection. |
| Container Loading (20′ FCL) | 20′ FCL container loaded with Evonik VESTAMID® Care ML18 Medical Grade Nylon 12, securely palletized, protected, and sealed for safe transport. |
| Shipping | Evonik VESTAMID® Care ML18 ships in sealed, moisture-barrier packaging to preserve purity and mechanical properties. Transport uses clean, dry containers with temperature control to prevent degradation. Handling follows medical-grade protocols, ensuring compliance with ISO standards and traceability from origin to destination. |
| Storage | Store Evonik VESTAMID® Care ML18 in its original, tightly sealed container in a cool, dry, well-ventilated area. Protect from direct sunlight, heat, and moisture, as nylon 12 can absorb humidity. Ideal storage temperature is below 30°C. Reseal immediately after use to maintain purity and prevent contamination. Use within recommended shelf life. |
| Shelf Life | Shelf life is typically 2 years when stored dry, cool, in original sealed packaging. |
In multi-lumen catheter shaft extrusion on a 25 mm barrier-screw single-screw extruder with L/D 25:1, the first process conflict occurs before the resin reaches the screw. VESTAMID Care ML18 is dried in a desiccant-bed dryer at 80 °C for 4 h to a residual moisture content below 0.10 wt% measured by ISO 15512; processing undried material produces splay, melt-pressure fluctuation, and annular surface defects. The barrel profile is set to 190 °C in zone 1, 210 °C in zone 2, 225 °C in zone 3, and 230 °C at the die. A gear pump between the screw and breaker plate holds pressure variation below 0.5 bar. For a triple-lumen shaft with an outer diameter of 1.2 mm and wall thickness of 0.15 mm, the melt pump is set to 8–12 kg/h, and laser-micrometer closed-loop control maintains outer-diameter concentricity at ±0.005 mm. When radiopaque barium sulfate is compounded at 20–30 wt%, die pressure rises and throughput drops unless the melt temperature is raised to 240 °C and screw speed is reduced to 30–45 rpm. The finished PICC catheter shaft is evaluated for liquid leakage and burst resistance under ISO 10555-1; each lot must carry current ISO 10993-5 and ISO 10993-10 documentation. Lot-to-lot melt volume-flow rate variation of ±5% alters screw-stroke position, so a pre-production trial is specified for each resin batch.
Water sorption in a jet nebulizer venturi channel shifts dimensional tolerance because VESTAMID Care ML18 absorbs approximately 1.5 wt% water at saturation in water at 23 °C under ISO 62, compared with roughly 9.5 wt% for unreinforced PA6. In a venturi channel with a critical width below 0.5 mm, this differential changes flow restriction under high-humidity respiratory gas conditions. The nebulizer housing is injection-molded in an 8-cavity cold-runner tool with a melt temperature of 230–250 °C, a mold temperature of 40–50 °C, a holding pressure of 600–800 bar, and a cooling time of 8 s. Vent depth is maintained at 0.02 mm by hardened S-136 tool steel inserts. Drying at 80 °C for 4 h to below 0.10 wt% residual moisture is required before molding. The molded nebulizer body, medication cup, and inspiratory valve seat are tested under ISO 18562-1 and ISO 18562-2 for volatile organic compounds and leachables in the gas pathway. Silicone mold release is excluded because it migrates into the condensate stream and complicates ISO 18562-3 toxicological assessment.
When two injection-molded VESTAMID Care ML18 halves are joined by near-field ultrasonic welding, the valve housing requires an energy director height of 0.2 mm and a shear-joint interference of 0.05 mm. The body and cap are molded on a 16-cavity hot-runner tool at a melt temperature of 235–245 °C, a mold temperature of 50–60 °C, a holding pressure of 700 bar, and a cooling time of 10 s. Welding runs at 20 kHz with an amplitude of 30–40 µm, a weld time of 0.10–0.25 s, a hold force of 300–500 N, and target energy of 20–40 J. Weld time above 0.30 s produces flash inside the fluid path and reduces the sealing face. After assembly, luer taper dimensions and leakage are verified against ISO 80369-7:2016; tightness is tested under the positive-pressure and negative-pressure conditions defined in the standard. The terminal component is a luer-activated check valve housing used in infusion sets. Biological evaluation follows ISO 10993-5 and USP <88> Class VI; ethylene oxide sterilization is possible at 55 °C with extended aeration because PA12 absorbs sterilant residues.
For autoclavable surgical handpiece clamshell housings, VESTAMID Care ML18 is injection-molded on an 8-cavity hot-runner tool with a melt temperature of 240–250 °C, a mold temperature of 60 °C, a holding pressure of 800 bar, and a cooling time of 12 s. Internal ribs are specified at a minimum thickness of 0.8 mm with a root radius of 0.25 mm; thinner ribs become vulnerable to creep at the lower base during vacuum-assisted steam autoclave cycles at 134 °C for 3 min under ISO 17665-1. Mold coolant enters at 20 °C in turbulent flow, and core deflection across the tool is held to 0.03 mm. The unreinforced polyamide 12 retains short-term heat resistance, but sustained load from spring-loaded trigger components during sterilization creates a deformation risk; published data for ML18 after 250 autoclave cycles is limited, so fixture-level creep testing is required before design release. The terminal component is a reusable surgical handpiece clamshell housing. Lot documentation includes ISO 10993-1 biological evaluation records; compatibility with hospital reprocessing detergents is tested separately.
| Conversion operation | Melt temperature | Tool/die temperature | Residual moisture target | Critical in-process control |
|---|---|---|---|---|
| Multi-lumen tube extrusion | 230–240 °C | Die 230 °C | <0.10 wt% by ISO 15512 | OD concentricity ±0.005 mm |
| Nebulizer venturi molding | 230–250 °C | Mold 40–50 °C | <0.10 wt% by ISO 15512 | Vent depth 0.02 mm |
| Luer check valve molding | 235–245 °C | Mold 50–60 °C | <0.10 wt% by ISO 15512 | Energy director 0.2 mm |
| Surgical handpiece molding | 240–250 °C | Mold 60 °C | <0.10 wt% by ISO 15512 | Rib thickness 0.8 mm |
| Needle-shield overmolding | 240 °C | Insert 120 °C | <0.10 wt% by ISO 15512 | Insert radial clearance 0.05 mm |
| Stopcock body molding | 235–245 °C | Mold 55 °C | <0.10 wt% by ISO 15512 | Female Luer thread wall 1.3 mm |
| Cable jacket extrusion | 200–220 °C | Crosshead 220 °C | <0.10 wt% by ISO 15512 | Jacket wall 0.30 mm, line speed 50–100 m/min |
Autoinjector needle-shield overmolding uses VESTAMID Care ML18 injected at 240 °C over a 316L stainless steel needle shield preheated to 120 °C inside the mold insert. Injection speed is 80–120 mm/s, holding pressure is 600 bar, and cooling time is 10 s. The overmolded wall thickness is 0.8 mm, and the steel insert is positioned with 0.05 mm radial clearance. If insert temperature drops below 80 °C, sink marks form at the gate and the overmolded surface loses dimensional specification. A 10 wt% barium sulfate masterbatch is used when radiopacity is required in the needle-shield housing. Drop testing of the assembled device is performed according to ISO 11608-1; the part is also inspected for cracks after 25 cycles of disinfection with 70% isopropanol. The terminal component is a single-use autoinjector needle-shield housing. Lot-specific ISO 10993-5 documentation is required, and the molder records melt-pressure curve signatures from each shot to detect lot-to-lot viscosity drift.
Where lipid emulsions and repeated alcohol disinfectants cause polycarbonate stopcock bodies to crack, VESTAMID Care ML18 is selected for improved stress-cracking resistance, but its lower flexural modulus means female Luer thread roots must be thickened from 1.0 mm to 1.3 mm. The stopcock body is molded in a 16-cavity tool with a melt temperature of 235–245 °C, a mold temperature of 55 °C, a holding pressure of 800 bar, and a gate diameter of 0.8 mm. After molding, dimensional inspection follows the luer cone geometry of ISO 80369-7:2016, including thread engagement and taper fit. Torque retention is measured after 10 connect–disconnect cycles under the standard’s test conditions. A gate diameter below 0.8 mm creates excessive shear heating and local white streaks at the thread root. The terminal component is a three-way stopcock body with integral luer connectors. Solvent bonding is replaced by ultrasonic welding or mechanical locking because PA12 has a narrower solvent-welding window than polycarbonate. Biological evaluation is documented under ISO 10993-5 and ISO 10993-10.
For reusable electrosurgical pencil cable insulation, VESTAMID Care ML18 is extruded on a 30 mm single-screw extruder with L/D 30:1 using a low-compression screw to limit shear heating. The barrel profile is 200–220 °C, the die is 220 °C, and screw speed is held at 20–30 rpm. The conductor is preheated to 80 °C before entering the crosshead, and the polyamide jacket is applied at a wall thickness of 0.30 mm with a line speed of 50–100 m/min. A desiccant dryer at 80 °C for 4 h maintains moisture below 0.10 wt%; wet resin produces a rough jacket surface and voids. VESTAMID Care ML18 is not inherently flame retardant, so IEC 60601-1 flammability requirements for medical electrical equipment require an additional flame-retardant masterbatch or outer jacket after verification. Dielectric withstanding voltage is tested according to IEC 60601-1; the insulation wall is checked for pin-holes by in-line spark testing. The terminal component is an electrosurgical pencil cable jacket for a reusable instrument. Material documentation includes ISO 10993-5 and ISO 10993-10.
| Application sector | Primary standard | Test or clause focus |
|---|---|---|
| Intravascular catheter shaft | ISO 10555-1, ISO 10993-5, ISO 10993-10 | Leakage, burst, cytotoxicity, sensitization |
| Respiratory gas pathway | ISO 18562-1, ISO 18562-2, ISO 18562-3 | VOC screening, leachables, toxicological evaluation |
| Luer check valve and stopcock | ISO 80369-7:2016, USP <88> | Dimensional fit, leakage, torque retention |
| Surgical handpiece housing | ISO 17665-1, ISO 10993-1 | Steam sterilization, biological evaluation |
| Autoinjector needle shield | ISO 11608-1, ISO 10993-5 | Drop resistance, dimensioning, cytotoxicity |
| Cable jacket for medical electrical equipment | IEC 60601-1, ISO 10993-5, ISO 10993-10 | Dielectric withstand, insulation integrity |
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Evonik VESTAMID® Care ML18 is a medical-grade polyamide 12 (PA12) supplied as cylindrical granules and positioned in the VESTAMID Care portfolio for extruded and injection-molded medical device components. The designation ML18 identifies a medium melt-viscosity PA12 in the medical Care series; its viscosity is between lower-viscosity grades used for short flow paths and higher-viscosity grades used for large-diameter extrusion. The material is selected for catheter shafts, multi-lumen tubing, introducer sheaths, and luer hubs where a combination of low water absorption, dimensional stability, lubricity, and fatigue resistance is required.
Published dry-as-moulded values commonly referenced for VESTAMID Care ML18 include the following.
| Property | Test method | Typical value |
|---|---|---|
| Density | ISO 1183-1:2019 | 1.01 g/cm³ |
| Melting temperature | ISO 11357-1:2018 / -3:2018 | 176 °C |
| Tensile modulus | ISO 527-1:2018 / -2:2018 | 1500 MPa |
| Tensile stress at yield | ISO 527-1:2018 / -2:2018 | 47 MPa |
| Nominal strain at break | ISO 527-1:2018 / -2:2018 | >200% |
| Flexural modulus | ISO 178:2019 | 1300 MPa |
| Shore D hardness | ISO 868:2003 | 68 |
| Water absorption, saturation at 23 °C | ISO 62:2008 | 1.4 wt% |
The first boundary is moisture. PA12 is hygroscopic and hydrolyses above the melt transition if residual moisture is not controlled. For VESTAMID Care ML18, the common processing limit is residual moisture below 0.10 wt% determined by ISO 15512:2019. Closed-loop desiccant dryers with a bed temperature of 80 °C and a dew point below -40 °C are typically specified for 4 h to 6 h before processing. Hopper residence above 4 h in uncontrolled ambient conditions above 60% relative humidity can return the material to an unprocessable moisture state; therefore hopper dryers rather than tray dryers are used on continuous catheter lines.
Melt temperature is the second limiting factor. The recommended melt-temperature window for this grade lies between 210 °C and 240 °C during tube extrusion. Barrel settings are commonly ramped from 180 °C in the feed zone to 230 °C at the metering zone, with the die head held at 220 °C to 235 °C. Residence time above 250 °C should be kept below 10 min to limit gel formation and yellowing; this is particularly difficult in multi-lumen crossheads with low purge volume. When tooling has dead spots, a documented start-up and shut-down purge with medical-grade, higher-viscosity PA12 is used to sweep degraded polymer from the flow path.
Shear and draw-down limits are less often cited but dominate line stability. Capillary rheometry performed to ISO 11443:2021 on PA12 at 230 °C shows a shear-thinning response; the onset of melt fracture in annular medical tubing dies typically appears when apparent shear rate exceeds 10⁴ s⁻¹ to 10⁵ s⁻¹, depending on die-land ratio and melt temperature. This onset moves upward as melt temperature increases from 220 °C to 240 °C, but the upper temperature is constrained by thermal degradation. Downstream, the vacuum sizing tank water temperature is normally maintained between 15 °C and 25 °C because rapid quenching increases skin crystallinity and improves dimensional control; excessive cooling below 10 °C can increase ovality in thin-wall multi-lumen profiles. Closed-loop laser OD gauges and ultrasonic wall-thickness transducers are used to maintain a wall-thickness tolerance of ±0.025 mm at line speeds ranging from 20 m/min to 80 m/min, depending on outer diameter and lumen geometry.
In multi-layer catheter shafts, ML18 is used as the outer layer or inner layer because its melt strength supports co-extrusion with polyether block amide or polyurethane layers. Interfacial adhesion depends on the tie layer and die temperature; the die-head temperature is selected at the upper end of the PA12 window only when the adjacent layer can tolerate it. On five-layer tubing lines, the PA12 layer is commonly processed from a separate single-screw extruder with melt pump to reduce pressure fluctuation below ±0.2 MPa. Feedblock and spiral mandrel dies with 10 to 20 spiral ports are used; pressure drop across the mandrel influences layer distribution and weld-line visibility.
The separation between VESTAMID Care ML18 and general-purpose VESTAMID L grades lies in supplier change control and biological evaluation, not in polymer chemistry alone. Medical Care grades are manufactured under defined raw-material specifications, dedicated change-management procedures, and batch documentation aligned with ISO 13485:2016. The result is a material with a controlled additive package and a biological evaluation package covering cytotoxicity per ISO 10993-5:2009, intracutaneous reactivity per ISO 10993-10:2021, acute systemic toxicity per ISO 10993-11:2017, and USP <88> Class VI. Extractable and leachable screening can be addressed under ISO 10993-18:2020, but extractables data are application-specific and require device-level validation.
Medical device moulders and extruders use VESTAMID Care ML18 under change-notification agreements. Evonik maintains a documented formulation lock and provides a certificate of analysis for each batch. A change-control notification period is part of supply contracts so that device manufacturers can run equivalency testing. This is a substantive difference from general-purpose polyamide 12, where an additive change may be made without a device-level revalidation pathway under ISO 10993-1:2018.
Compared with lower melt-viscosity grades in the same Care series, ML18 offers higher melt strength during free-draw and sag-prone processes. Compared with higher melt-viscosity grades, it produces lower melt pressure in small-diameter multi-lumen tooling and thin-wall connectors. The practical consequence is that ML18 is often specified when one material must serve both tubing and injection-molded hub applications within a single device family, avoiding a second validation. Against polyamide 11, PA12 absorbs less moisture and typically provides a lower coefficient of friction; against polyether block amide, ML18 has higher tensile modulus and better collapse-resistance at elevated temperature; against polyamide 6 or PA66, it offers lower saturated water uptake and less loss of stiffness after conditioning to 50% relative humidity.
Injection moulding with VESTAMID Care ML18 follows the same moisture limit but uses a different thermal history. For multicavity luer-hub tools, barrel temperatures from 220 °C to 250 °C and mould temperatures between 40 °C and 80 °C are representative. Higher mould temperatures increase crystallinity and improve dimensional reproducibility at the cost of longer cycle times; lower mould temperatures reduce cycle time but can cause retained amorphous skin and post-mould shrinkage. Hot-runner systems with valve-gate control and polished melt channels below 3 mm diameter are preferred to minimize stagnation.
Because ML18 is a medium-viscosity grade, injection pressures for thin-wall connectors generally remain below 100 MPa in 16- to 32-cavity tools when the runner system is balanced. Cavity-to-cavity weight variation is commonly held below 0.5% with closed-loop injection speed control and hot-runner tip temperature variation below 5 °C. Moulded-in stress can be reduced by post-mould annealing at 60 °C for 2 h in a forced-air oven, but annealing cycles must be validated for warpage and dimensional shift.
Part designers should account for post-mould shrinkage of approximately 0.8% to 1.5% depending on wall thickness and mould temperature. Gate position at the luer hub base should allow polymer to flow from the hub into the lumen without weld lines at the lumen opening. In tools with hot-runner thermal gates, gate temperature should remain below 250 °C to avoid local degradation at the gate tip. Screw decompression after plastication should not exceed 2 mm to prevent air entrapment and splay on transparent parts.
Flow hesitation can occur at wall-thickness steps below 0.4 mm or when a luer taper is fed from a subgate without a cold slug well. This grade is not recommended for components with nominal wall thickness below 0.3 mm unless processing trials confirm complete fill; published data for this specific configuration is limited.
VESTAMID Care ML18 is commonly sterilised with ethylene oxide and is compatible with gamma irradiation at doses up to 50 kGy; at higher doses the polymer can undergo chain scission and embrittlement. Steam sterilisation at 121 °C produces a transient exposure above the glass transition temperature and repeated cycles can increase water absorption and dimensional change; steam exposure should be validated for device geometry and residual stress. Dry heat sterilisation above 150 °C is not recommended because of oxidative discoloration and loss of ductility.
Chemical resistance follows general PA12 behaviour: the material resists aliphatic hydrocarbons, hydraulic fluids, and saline solutions, but is attacked by strong mineral acids, hydrofluoric acid, and strong oxidising agents. Alcohols and plasticising oils can cause stress cracking under high moulded-in stress. Chlorinated solvents are not recommended as cleaning agents. Avoid compounding with amine-based additives or exposed copper-based stabilisers that can promote thermo-oxidative degradation; the Care grade is formulated with a defined additive package that should not be altered by processors.
Because PA12 is hygroscopic, VESTAMID Care ML18 must be stored in sealed moisture-barrier packaging below 0.10 wt% moisture. Containers opened for more than 2 h in ambient conditions above 60% relative humidity require re-drying. In extrusion or injection moulding, regrind from medical production is generally not reintroduced unless validated for biocompatibility and molecular-weight retention. The grade is not intended for permanent implantation in high-load orthopaedic bearings; its use is concentrated in short-term and long-term device components where flexibility, lubricity, and dimensional stability under humidity are dominant requirements.
