An injection-moulding grade of Lucobit AG Lucopren® SBS SB 1551-60S is specified for soft-touch overlays on hand tools and power tool housings when a low-hardness elastomeric surface must be combined with a rigid thermoplastic substrate. The material is processed as an overmould onto glass-filled polypropylene or PC/ABS substrates on a two-shot injection moulding machine with a rotary platen. Barrel temperature settings are typically 160–190 °C from feed throat to nozzle, with the nozzle held at 185–195 °C. Mould temperature is maintained at 20–35 °C. The substrate is pre-heated to 40–60 °C or surface-treated by plasma discharge before overmoulding because SBS 1551-60S develops only limited chemical adhesion to untreated polypropylene. Injection speed is set to 40–80 cm³/s through gates of 1.5–2.5 mm diameter. Holding pressure is kept at 300–600 bar for 2–5 s, followed by 8–15 s cooling. Colour is adjusted with 2–3 wt% styrenic colour masterbatch. A stabiliser package of 0.2–0.4 phr hindered phenolic antioxidant and 0.3–0.8 phr UV absorber is used when the tool housing is exposed to workplace lighting or intermittent outdoor use. Hardness is checked on a 6 mm plaque according to ISO 868 and is required to remain within ±3 Shore A of the nominal 60 Shore A specification. Tensile strength and elongation are determined according to ISO 37 on type 2 dumbbells at 500 mm/min. Adhesion failure is evaluated visually after 24 h at 23 °C; peeling or delamination at the SBS-substrate interface is cause for rejection. Compliance for articles placed on the EU market includes REACH Regulation (EC) No 1907/2006 Annex XVII entry 50 for polycyclic aromatic hydrocarbons in rubber or plastic parts with direct skin contact and RoHS Directive 2011/65/EU for electrical tool housings. The grade is not specified for food-contact use unless lot-specific migration testing is performed. Finished articles include overmoulded grips on cordless screwdrivers, angle grinders, and handheld power tools.

What Limits Colour Stability and Slip Resistance in Calendered Anti-Fatigue Mats?

Calendered anti-fatigue mats based on SBS 1551-60S are produced on a three-roll calender in L or inverted-L configuration. Roll temperatures are set at 140–160 °C for the middle and bottom rolls and 130–150 °C for the top roll. The friction ratio between rolls is held at 1.1:1–1.3:1 to generate controlled shear heating without scorching the polybutadiene mid-blocks. The compound is pre-mixed in a tangential mixer at 110–130 °C, then passed through a strainer extruder with barrel temperatures of 120–140 °C to remove gels larger than 100 µm. For indoor industrial mats, the formulation may contain 20–35 phr calcium carbonate filler, 5–15 phr paraffinic or naphthenic oil, and 0.5–1.0 phr zinc stearate as an internal release agent. For outdoor or high-UV service, a stabiliser package of 0.3–0.8 phr UV absorber, 0.2–0.5 phr hindered amine light stabiliser and 2–3 phr carbon black is required, because residual unsaturation in the butadiene phase causes surface chalking and discolouration under xenon-arc exposure according to ISO 4892-2. Slip resistance is measured according to EN 13893 or DIN 51130. A targeted R10 rating under dry and wet conditions is achieved with an embossed surface generated by a chilled embossing roll at 30–40 °C. Thickness control is maintained within ±0.3 mm across the web, because edge thinning changes deformation under foot load. Compliance for industrial mats placed on the EU market includes REACH Annex XVII entry 50 PAH limits and, where relevant, construction products regulation requirements. Published data for this specific mat configuration is limited; lot-specific mechanical and slip tests are required before series production. Finished goods include modular anti-fatigue mats for assembly lines, commercial kitchen floors, and standing workstations.

Footwear Sole Compounds: Mould Release, Shrinkage, and DIN Abrasion

Footwear sole production with SBS 1551-60S is carried out either by direct injection moulding or by compression moulding. In formulations where the grade is used as the elastomeric base, a typical sole compound contains 70–80 wt% SBS 1551-60S, 10–20 wt% general-purpose polystyrene for hardness and abrasion improvement, 5–10 wt% naphthenic oil, 5–20 wt% calcium carbonate filler, 0.3–0.5 phr phenolic antioxidant, and 0.5–1.0 wt% zinc stearate. Direct injection moulding uses a reciprocating screw machine with barrel temperatures of 165–190 °C and a clamp force of 800–1500 kN for multi-cavity sole moulds. Compression moulding uses pre-heated slugs at 140–160 °C and 6–10 min moulding pressure of 15–25 MPa. The processing window is narrow. Above 195 °C, oxidative degradation of the polybutadiene mid-block produces gel specks and reduces elongation. Below 160 °C, weld-line strength in multi-gate soles is insufficient and visible flow lines form. Mould release is a production bottleneck because SBS has high hot tack under ejection conditions. External mould-release agents based on 0.5–1.0 wt% zinc stearate or PTFE-coated mould surfaces are required to prevent tearing at ejection pin marks. Post-moulding shrinkage is anisotropic, measured at 1.0–1.8% in the flow direction and 0.5–1.0% transverse after 24 h at 23 °C, according to ISO 294-4. Soles are conditioned for 24 h before hardness is checked with ISO 868. The target hardness is 60 Shore A with a tolerance of ±3 points. Tensile strength is determined on ISO 37 type 2 dumbbells at 500 mm/min. Abrasion resistance is measured according to ISO 4649 method A; values above 250 mm³ are rejected for safety footwear outsoles. Flexural fatigue is evaluated according to ISO 16177:2021 for crack initiation at 30 000 cycles. Adhesive bonding to leather or textile uppers is performed with polyurethane-based cements; natural rubber latex cements are not recommended because SBS swells and loses bond strength in hydrocarbon solvents. Regulatory compliance for footwear includes REACH Annex XVII entry 50 PAH limits for skin contact. RoHS is not normally applicable to non-electrical footwear unless metallic accessories are integrated. Finished soles and midsoles are used in sandals, casual shoes, and work safety footwear.

Extruded appliance seal profiles from SBS 1551-60S are produced on a single-screw extruder with 25:1–30:1 L/D and a screw compression ratio of 2.5:1–3.0:1. The screw is cooled to 80–100 °C in the feed zone to prevent pellet bridging. Barrel zones are profiled from 160 °C at the feed throat to 180 °C at the die. The die head is held at 175–185 °C. A breaker plate and screen pack of 60/100 mesh are used to generate back pressure and remove gels. The profile is calibrated in a water trough at 15–25 °C with vacuum sizers. Post-extrusion shrinkage of 0.8–1.2% occurs within 48 h, so cutting tolerances for freezer door gaskets are set at 2–3 mm per metre. If the grade is used as supplied, additional external plasticiser is generally not required, which reduces surface bloom and migration to painted cabinet surfaces. Compression set is measured by ISO 815-1 at 70 °C for 22 h; values above 50% indicate insufficient recovery for sealing. Low-temperature flexibility is measured by ISO 2921; the profile must remain flexible at −20 °C for freezer applications. Compliance for appliance seals includes Regulation (EC) No 1907/2006 and RoHS Directive 2011/65/EU where electronic components are integrated. No phthalate plasticisers are used in the unmodified grade. Direct food-contact declarations are outside the specification unless migration testing under EC 1935/2004 is performed. Finished goods include freezer door gaskets, low-heat appliance bumpers, and flexible retaining strips.

When SBS 1551-60S Is Injection-Compression Moulded Into Suction Cups and Sealing Rings

When a Shore A 60 SBS compound is specified for suction cups and sealing rings, injection-compression moulding is preferred over straight injection moulding because the compression phase produces lower internal stress and improves dimensional stability. Machine parameters are barrel temperature 170–195 °C, compression stroke 2–5 mm, compression force 600–1200 kN, and venting 0.2–0.5 s. The mould is held at 25–40 °C. Cavities with polished surfaces are used because SBS develops vacuum adhesion to glass and glazed ceramic only when the contact surface is free of sink marks. Surface irregularity above 0.1 mm creates a leak path. Formulation includes 0.5–1.0 phr antioxidant and 0.3–0.6 phr mould-release lubricant to reduce ejection tack. No external plasticiser is needed, so migration to the contact interface is minimal. Air permeability through the butadiene phase limits long-term holding force; published data for this specific configuration is limited and product-specific holding-force tests are required. Product qualification includes tensile strength by ISO 37, hardness by ISO 868, and compression set by ISO 815-1 method A at 23 °C for 72 h. The finished part must recover to 80–90% of original height within 60 s after unloading. Compliance for suction cups placed on the EU market includes REACH Annex XVII entry 50 PAH limits and RoHS Directive 2011/65/EU. Food-contact and medical suction devices are outside the grade boundary unless specific migration and biocompatibility testing are completed. Finished articles include automotive dashboard suction mounts, household hooks, and vacuum-fixture sealing rings.

Impact Modification of Recycled Polystyrene Using SBS 1551-60S

Compounding of SBS 1551-60S with recycled general-purpose polystyrene is carried out on a co-rotating twin-screw extruder with 30:1–40:1 L/D and a barrel profile of 180–200 °C. SBS is fed as 5–20 wt% into the first barrel section. A distributive mixing section with kneading blocks at 45°–60° staggering is used to generate dispersion without excessive shear heating. Screw speed is set to 250–400 rpm. A vacuum vent at 0.08–0.09 MPa removes volatiles from recycled PS. The extrudate is strand-pelletised after water cooling to 30–40 °C. Impact performance is measured on injection-moulded specimens according to ISO 180/A notched Izod at 23 °C. Addition of 10 wt% SBS 1551-60S typically moves the failure mode from brittle crack to hinge break in thin-wall parts; published data for this specific recycled feedstock is limited. Melt flow index is determined by ISO 1133-1:2022 at 200 °C/5 kg. SBS addition reduces MFR, so gate size and injection pressure must be increased by 10–20% compared with unmodified recycled PS. Processing temperature must not exceed 200 °C, because recycled PS may contain residual contaminants that accelerate SBS degradation. Compliance for electrical appliance housings includes RoHS Directive 2011/65/EU. PAH restrictions under REACH Annex XVII entry 50 apply if the final article is sold in the EU and sustains direct skin contact. Finished goods include appliance housings, coat hangers, and office accessories.