VESTAMID® E47-S1 is supplied as an unfilled, plasticiser-free polyether block amide (PEBA) resin in which polyamide 12 forms the semi-crystalline hard segment and polyether forms the elastomeric soft segment. The product nomenclature identifies the nominal Shore D durometer target of 47 when measured on an injection-moulded plaque according to ISO 868. As a nylon 12 elastomer, it is not an externally plasticised compound and therefore does not exhibit the progressive surface tack, squeeze-out, or plasticiser migration associated with flexible PVC or monomeric plasticiser systems. Manufacturer-published typical property data for dry-as-moulded specimens conditioned at 23 °C and 50 % relative humidity are summarised below.

The combination of density at 1.02 g/cm³ and flexural modulus at 210 MPa is significantly below the stiffness of polyamide 12 homopolymer grades, while the dry, non-migrating surface remains functional under repeated flexural loading. At subzero temperatures, the polyether soft block retains segmental mobility; dynamic mechanical analysis of comparable PEBA chemistries places the soft-segment glass transition below -40 °C, although published data for this specific grade in complex part geometry is limited. Moisture saturation of 1.3 % according to ISO 62 indicates that absorbed water acts as a mild plasticiser, reducing hardness and increasing elongation at equilibrium. This moisture response must be incorporated into dimensional tolerance stacks and hot-wet service evaluations rather than treated as a simple surface condition.

What Conversion Parameters Minimise Gate Splay and Freeze-Off in Thin-Wall Components?

Pre-drying represents the first conversion control for VESTAMID® E47-S1. Incoming pellets should be dried in a dehumidifying dryer with a dew point no higher than -40 °C at 80 °C for 4 h to 6 h to reduce residual moisture below 0.10 % by weight. Moisture above 0.15 % hydrolyses the PA12 hard block during plastication; the resulting melt pressure drop at the nozzle, surface splay, and reduction in notched impact strength are observed on production-scale injection moulding machines fitting 35 mm general-purpose screws with L/D 22. Melt temperatures measured at the nozzle should remain between 210 °C and 250 °C. Prolonged residence time above 280 °C causes oxidation of the polyether soft segment and a shift toward higher yellowness index.

Mould temperatures of 20 °C to 60 °C are used, with the upper half of the range applied to wall sections below 1.5 mm to delay premature gate freeze. Representative processing windows on a 30 mm screw include injection velocities of 100 mm/s to 250 mm/s, hydraulic holding pressure of 40 MPa to 60 MPa, back pressure of 5 MPa to 10 MPa, and screw speed of 60 min⁻¹ to 100 min⁻¹. Because E47-S1 has lower viscosity than semi-crystalline PA12 homopolymer at equivalent melt temperature, transfer from existing PA12 settings frequently produces overpacking and mould flash. A gate-seal study should therefore be performed to determine holding time; the lower melt viscosity also reduces cushion stability if screw recovery is short. In thin-wall connectors and snap-fit housings, freeze-off at the gate is the primary constraint, not melt temperature at the front zone.

For melt extrusion of tubing and cable sheathing, a single-screw extruder with L/D 24 to 30, a barrier screw with compression ratio 2.5:1 to 3.0:1, and breaker-plate screen packs of 40/60/80 mesh is suitable. Melt temperature at the adapter should not exceed 250 °C for extended campaigns, because the polyether segment is the thermolabile portion of the block copolymer. Batch-to-batch viscosity deviation on a 25 mm instrumented extruder is typically controlled within 5 % when incoming pellet moisture and regrind ratio are held constant. Regrind addition up to 20 % does not produce meaningful hardness shift in dry-blend operation, but higher levels alter shear heating and should be validated with melt flow rate measurement according to ISO 1133-1.

In cable sheathing and pneumatic tubing, the absence of external plasticiser becomes operationally significant. Plasticised PVC and externally plasticised flexible nylon compounds can exhibit surface migration that contaminates connector contacts or reduces flexibility after thermal ageing. Because VESTAMID® E47-S1 obtains its 47 Shore D hardness from block architecture rather than additive plasticisation, extractable content remains low. Converters should nevertheless verify specific global migration against (EU) 10/2011 or 21 CFR 177.1500 when food-contact or potable-water certifications are required for the finished article, because processing residues and regrind history affect final compliance. For hydraulic and pneumatic tube applications, the PA12 block imparts resistance to aliphatic hydrocarbons, greases, and zinc-free hydraulic fluids, while the polyether block reduces flexural modulus for tighter minimum bend radius. Long-term fluid exposure should be evaluated by volume and mass change according to ISO 175, since chlorinated hydrocarbons, ketones, and strong polar solvents cause measurable swelling. The material is suitable for co-extrusion with PA12 and polyamide-based tie layers, provided the adapter temperature remains below 250 °C to avoid degradation between layers.

Sports footwear sole units and ski boot components injection-moulded from E47-S1 are normally gated at the thickest article section. The low flexural modulus allows articulation zones to flex without stress whitening. Cyclic flexural loading at 23 °C should be evaluated by flexural fatigue methods rather than tensile data alone, because the strain field in a sole unit involves bending and recovery rather than uniaxial extension. In two-shot moulding with rigid PA12 or thermoplastic polyurethane substrates, melt temperature mismatch should be kept within 20 °C at the interface to avoid freezing before bond formation. Where texturing is required, higher mould temperatures within the 40 °C to 60 °C range improve grain replication without producing polyether degradation.

Comparative Shore Hardness and Flexural Modulus Across the VESTAMID E Family

Grade selection within the VESTAMID E family is governed by Shore D hardness. VESTAMID E40-S1 carries a Shore D hardness of 40 according to ISO 868, placing it below E47-S1 for snap-fit retention and bending stiffness. VESTAMID E55-S1 carries a Shore D hardness of 55, giving higher flexural modulus and better resistance to buckling in thin-wall profiles, but with reduced low-temperature elasticity relative to E47-S1. VESTAMID E62-S1, at Shore D 62, approaches lower-stiffness PA12 homopolymer behaviour while retaining elastic recovery. The hardness progression is not linear in modulus; a durometer increase from 47 to 55 produces a proportionally larger gain in bending resistance than the raw durometer spread suggests. Finite element analysis for snap-fit designs should therefore use a secant modulus at the intended design strain rather than the initial flexural modulus of 210 MPa.

Compared with polyamide 12 homopolymer, VESTAMID® E47-S1 is substantially more compliant. PA12 homopolymer grades typically exhibit flexural modulus in the range of 1,300 MPa to 1,500 MPa, roughly an order of magnitude above E47-S1. This difference is critical for snap-fit and living-hinge applications; the homopolymer provides rigidity and dimensional stability, while E47-S1 supplies recovery after bending and lower stress concentration on adjoining features. When replacing PA12 homopolymer with E47-S1, wall stock should not be reduced without evaluating creep modulus at the service temperature according to ISO 899-1, because the lower initial modulus does not imply equivalent long-term deformation resistance under load.

Unlike plasticised nylon 12 compounds that achieve flexibility through external plasticisers, E47-S1 retains flexibility through covalent bonding between PA12 hard blocks and polyether soft blocks. This structural difference reduces plasticiser loss during thermal ageing and eliminates interfacial bloom at elevated humidity. However, the polyether block is more oxidatively sensitive than PA12 alone, so hot-air ageing resistance is not equivalent to unplasticised PA12 homopolymer. The product should not be regarded as a direct drop-in for PA12 homopolymer in under-hood automotive lines where continuous dry heat above 125 °C is encountered.

When E47-S1 Replaces Plasticised PVC in Seals and Flexible Mandrel Hoses

When E47-S1 is specified for dynamic seals, diaphragms, or flexible mandrel hoses, the service boundary is set by hysteresis build-up and solvent uptake rather than by initial hardness alone. Under cyclic strain, PEBA materials of this hardness class can accumulate heat in thick sections. Parts above 6 mm cross-section should be tested for internal temperature rise at the intended operating frequency, because internal heat generation may exceed the heat-transfer capacity of the part and produce premature softening or stress relaxation. Continuous hot-air exposure above 125 °C causes oxidative degradation of the polyether block, and published data for long-term hot-air ageing at 150 °C is limited. Swelling resistance to aliphatic hydraulic fluids and greases is governed by the PA12 hard block, but aromatic hydrocarbons, ketones, chlorinated solvents, and concentrated acids cause appreciable volume change and should be screened by ISO 175 before production release.

After saturation moisture uptake of 1.3 % by ISO 62, equilibrium moisture reduces hardness and increases elongation. Dimensional changes of 0.4 % to 0.7 % are possible depending on wall section, so seals with close clearances should be qualified on conditioned prototypes rather than dry-as-moulded dimensions. For potable water, food-contact, or medical device use, migration and biocompatibility verification to (EU) 10/2011, 21 CFR 177.1500, or ISO 10993 should be generated for the specific final article. RoHS and REACH declarations should be confirmed with the supplier, but the absence of external plasticiser is an advantage when documenting low extractable content.

The product should be stored in sealed packaging and re-dried before processing if exposure to 60 % relative humidity exceeds 4 h. In multi-layer mandrel hose construction, adhesion to PA12 inner liners is generally favourable because the PA12 hard block provides interfacial compatibility, while adhesion to high-hardness TPU may require a tie layer. When moving from plasticised PVC to E47-S1, the minimum bend radius should be re-calculated using the part’s actual wall thickness and flexural modulus of 210 MPa rather than transferred directly from PVC design tables, because the strain distribution in the bent tube differs from the plasticised PVC reference condition.