The 70 Shore A overmoulding window on PP door handle pockets and console trays

Two-component interior components in which a talc-filled PP carrier is overmoulded with BADAFLEX® SEBS-Comp. TPE-S 70A 1802LD 2K are transferred through a rotating-platen cell with a 180- to 350-tonne clamping force. The soft-component injection unit is normally a 25 mm three-zone screw with L/D 24, fed from dehumidified hoppers; the PP carrier is injected first at melt temperatures of 220–250 °C while the TPE-s phase is introduced at nozzle temperatures of 180–220 °C. The grade is a ready-to-use SEBS compound; no oil extension or vulcanisation additive is required, and any colour masterbatch should be based on an EVA or PP carrier at 1.5–2.5 wt% of the soft-component feed. Regrind from soft-component sprues and runners is limited to ≤20 wt% because higher rework fractions reduce the wetting of the PP interface and increase the probability of gate-area delamination. The soft-component mass fraction in finished handle pockets and console trays is typically 10–15 wt% for a 1.5–2.0 mm TPE layer over a 2.0–2.5 mm PP substrate; the layer thickness is not a free parameter when the visible surface must pass OEM abrasion and hand-cream exposure protocols. Thermal transfer at the second station should keep the PP substrate surface above 60 °C, measured by contact pyrometer, before soft-component injection; a drop below 50 °C produces a low-molecular-weight PP skin that inhibits interdiffusion and yields spatula-assisted peeling at the bond line.

Regulatory controls for automotive cabin materials include REACH Regulation (EC) No 1907/2006 Article 33(1) SVHC communication at 0.1% w/w, RoHS Directive 2011/65/EU Annex II with lead ≤0.1% and cadmium ≤0.01%, and component-level VOC/fogging limits determined by OEM methods such as VDA 278:2016-07 and DIN 75201:2011-06 method B. The compound should be reviewed against the Global Automotive Declarable Substance List (GADSL) because SEBS compounds can contain mineral oil extenders, though the 1802LD 2K designation is intended for low-emission interior use. In production, the PP carrier is moulded at high speed with a hot-runner manifold; the TPE-s overmould is gated through a cold sprue or edge gate with a vent depth of 0.01–0.02 mm on the parting line to avoid gas trapping at the intersecting rib bases. Foaming of the SEBS melt is observed when residual moisture exceeds 0.05%; if storage humidity is above 60% RH, pre-drying at 70–80 °C for 2–3 h in a desiccant dryer to a dew point of −30 °C restores a stable melt. Terminal parts include door handle pockets, console tray liners, and coin trays, all of which must survive short-cycle interior heat exposure without visible gloss shift or adhesion loss.

During two-component injection moulding of handheld gardening equipment grips, the same SEBS compound is overmoulded onto 30 wt% talc-filled PP handles where the bond line is loaded under torsional shear rather than simple peel. The soft component is metered as an ungated cold runner through a 14 mm nozzle; dosing by volume rather than weight eliminates check-ring leakage that is magnified by the low melt viscosity at 200 °C. The addition ratio of the TPE-s phase is constrained by the grip geometry: for a 32 g PP handle core, the overmould is 4–5 g, corresponding to 11–13 wt% of the finished part. The formulation is processed neat; if UV stabilisation is required for outdoor equipment, a hindered amine light stabiliser masterbatch is added at ≤2.0 wt% with PP carrier, but the stabiliser package must be pre-evaluated because some low-molecular-weight amine species migrate to the bond line and reduce adhesion after ultraviolet ageing. Mechanical safety of hand tools is assessed under ISO 13732-1:2006 for surface temperature limits on handles; REACH and RoHS 2011/65/EU apply, and the material is not classified as hazardous under CLP Regulation (EC) No 1272/2008. The sequential mould cycles use a rotary table with 4 stations; station one injects PP, station two overmoulds TPE-s, station three holds the grip under clamp force for 12 s, and station four ejects. The PP core is ejected at a temperature above 70 °C and transferred within 8 s to prevent crystallinity build-up that can reduce interfacial interlocking. The mould is textured to VDI 3400 surface finishes in the grip area; the TPE-s melt fills texture from the gate side without hesitation marks if injection velocity is kept above 30 mm/s. Published data for specific fuel resistance of this grade in two-stroke contact is limited; aromatic solvent contact should be restricted to short accidental exposure rather than continuous immersion. Finished products include hedge-trimmer and loop-handle grips, lawnmower control levers, and handheld pruner grips.

Can a TPE-S compound replace vulcanised EPDM in household appliance door seals?

Household detergent dispenser door seals overmoulded onto PP drawer housings replace vulcanised EPDM only when the functional demand is limited to water and dilute detergent contact rather than hot concentrated bleach. The soft seal is produced from the compound at 100% of the soft-seal volume; a PP-carrier colour masterbatch at 2.0 wt% is the only addition because the finished part must resist swelling in 5% sodium carbonate solution at 40 °C without hardness drop below 65 Shore A. If a hardness reduction is required, a softer grade from the same SEBS series is substituted instead of blending with process oil, because oil migration changes the coefficient of friction and reduces the seal recovery rate. The applicable regulatory baseline for electrically operated appliances is IEC 60335-1:2020 for general safety, while REACH Article 33(1) applies to SVHC communication; for food-contact detergent drawer seals, Regulation (EC) No 1935/2004 and Good Manufacturing Practice Regulation (EC) No 2023/2006 apply to the finished article rather than to the polymer alone. Chemical resistance is verified according to ISO 175:2010 for the specific detergent matrices encountered in service. The seal is produced on a two-shot mandrel mould with a rotating core set; the PP frame is injected at station one, and the TPE-s seal is injected at station two through a diaphragm gate to generate uniform thickness of 1.0–1.5 mm. The clamp force is maintained at 120–180 tonnes; cooling time for the TPE-s is 12–15 s at a coolant temperature of 30 °C. The compound is not recommended for gaskets exposed to sodium hypochlorite at concentrations above 5% at 60 °C; stress cracking has been documented in similar styrenic block copolymers under repeated chlorine exposure. Finished parts include dishwasher detergent drawer gaskets, washing-machine dispenser housing seals, and condensate drain grommets.

In blow-moulded PP closure gaskets for agrochemical and detergent packaging, permeation through the 2K liner, not bulk softening, determines shelf-life. The liner comprises 2.0–3.5 wt% of the total cap mass; the TPE-s phase is used without dilution, and slip masterbatch addition must be ≤1.0 wt% because erucamide-type slip agents bloom to the surface and reduce cap-liner adhesion. The closure system is tested under UN Model Regulations Chapter 6.1 for dangerous goods if used with agricultural chemicals; child-resistant closures may be tested according to ISO 8317:2015. The PP cap is injection-moulded in a separate multi-cavity tool and transferred to a rotary liner moulding station with core-cooling at 10 °C; the liner is injection-moulded through a hot-runner needle valve at a melt temperature of 190–210 °C to minimise degradation, with a hold pressure of 25–35 bar. The liner thickness is 0.8–1.2 mm; post-mould steam sterilisation at 121 °C for 20 min is feasible if the cap substrate is PP homopolymer rather than random copolymer. Finished closures include child-resistant caps for bleach, herbicide concentrates, and liquid detergent spouts.

Respiratory therapy mask cushions under overnight skin-contact conditions

The soft cushion is overmoulded onto a PP mask frame to create a seal that must remain conformable without evolving extractable substances beyond the limits set by ISO 10993-5:2009 cytocompatibility testing. The compound is used as-supplied; no release agents, mineral oil, or colour masterbatch are added because the material is assessed as a neat system. If colour is required, only a pre-compounded medical-grade masterbatch validated under ISO 10993-5:2009 is permitted, and addition is capped at 2.0 wt%. Biocompatibility evaluation follows ISO 10993-1:2020 and irritation testing follows ISO 10993-10:2013; USP 88 Class VI criteria may be referenced for specific customer specifications, and the finished device falls under EU MDR 2017/745. Injection moulding of mask cushions uses a 2K rotary platen machine with cleanroom-compliant oil-free clamping; the PP frame is moulded at 230–250 °C, and the cushion is overmoulded at 190–210 °C. The cushion gate is a pin-point gate at the nasal bridge; fill time 0.8–1.2 s prevents flow lines, and the mould surface is polished to SPI A-2 to reduce skin friction. After moulding, the assembled mask is subjected to ethylene oxide or hydrogen peroxide sterilisation; the grade must not be steam-sterilised above 121 °C because dimensional swelling of the SEBS phase exceeds 2% and can break the bond to the PP frame. Skin lipid absorption may increase surface mass slightly over repeated use, but published data for this specific configuration is limited; single-use and multi-patient applications require device-level validation. End products include CPAP mask cushions, nebulizer mask facial seals, and emergency ventilator mask rims.

When 2K bonding must survive damp-heat ageing in handheld electronics

After damp-heat ageing at 85 °C and 85% RH, the bond line of handheld electronics enclosures overmoulded onto flame-retardant PP is assessed for peel resistance and dimensional stability under ISO 62:2008. The BADAFLEX® SEBS-Comp. TPE-S 70A 1802LD 2K is used for sealing edges and battery-door buffers on remote controls and barcode scanners; the PP substrate is typically flame-retardant PP with 20–30 wt% talc. The compound is dosed neat; if anti-static masterbatch is added, it must be limited to 2.0 wt% to avoid migration to the sealing lip and a loss of surface resistivity consistency. The applicable compliance baseline is RoHS Directive 2011/65/EU Annex II, with sample preparation according to IEC 62321-2:2021; enclosure materials are typically evaluated for flame retardancy under UL 94 HB or UL 94 V-2, depending on the device end-use. The tool uses a valve-gated hot-runner for PP; the TPE-s cold runner is equipped with a pneumatic shut-off and is injected at the centre of the PP substrate rather than at the edges to avoid jetting. Gas-vent depth is 0.015 mm on the parting line. Post-mould annealing at 80 °C for 1 h improves bond-line wetting but can increase gloss if the seal surface is not textured to at least VDI 3400. If the PP substrate contains high levels of external mould release agents, IPA wiping before overmoulding is required; silicone-free PP is preferred. Published peel-strength values for this grade after 85 °C/85% RH ageing on flame-retardant PP are limited, so tool-level validation is required before series release.

Finished handheld electronics parts include TV and set-top box remote control battery seals, barcode scanner handle bumpers, and handheld RFID reader edge guards. These components are produced with short cycle times and low melt temperature to avoid heat damage to pre-assembled PP frame features.