In hot-melt pressure-sensitive adhesive compounding, LCY Chemical Huizhou Globalprene® SBS 3412P is charged as the elastomeric backbone into a jacketed sigma-blade mixer with a working volume of 500 L to 1,000 L at 160 °C to 180 °C. The pre-blend is typically composed of 100 phr SBS 3412P, 80 phr to 120 phr of a C5/C9 tackifier, 20 phr to 40 phr of naphthenic oil, and 0.3 phr to 0.5 phr each of a hindered phenol and a phosphite antioxidant. Melt viscosity is measured with a Brookfield thermosel viscometer per ASTM D3236 at 177 °C; process control limits are commonly set between 8,000 mPa·s and 25,000 mPa·s for spindle 27. Loop tack is evaluated following PSTC-16 on stainless steel panels; values from 3.5 N/25 mm to 8.0 N/25 mm are obtained when the tackifier softening point is between 95 °C and 110 °C. Peel adhesion is tested according to ASTM D3330/D3330M at a 180° peel angle; carton-sealing hot-melt specifications often require not less than 12 N/25 mm. Shear adhesion failure temperature is monitored by ASTM D3654/D3654M; hold times above 50 min under 1 kg loading at 50 °C are indicative of sufficient cohesive strength. The operating boundary is absolute: prolonged melt temperatures above 200 °C cause oxidative chain scission in the butadiene mid-block, gel speck formation, amber color shift, and a measurable loss in peel strength. Nitrogen blanketing of the melt vessel and continuous recirculation through a gear pump reduce stagnant hot-spot formation at the heating wall. Published data for this specific configuration is limited; incoming lots should be evaluated on a 25 mm single-screw extruder before plant-scale adhesive coating.

Adhesive performance is not controlled solely by the elastomer content. The aromaticity of the tackifier determines the degree of compatibility with the polystyrene domains; excessive C9 content lowers melt viscosity but reduces high-temperature shear holding power, while excessive C5 content causes phase separation and a loss of tack. The SBS 3412P addition is therefore fixed only after a ternary contour plot is generated across tackifier, oil, and antioxidant additions. Slot-die coating on polyethylene terephthalate release liners requires a melt temperature of 165 °C to 175 °C and a coating weight of 25 g/m² to 40 g/m²; intermittent coating heads are preferred over fixed slot dies when frequent grade changes are scheduled. Substrate failure analysis on production lines shows that adhesive transfer at low peel angles occurs when tackifier content exceeds 120 phr; below 80 phr, peel strength drops below 8 N/25 mm on recycled corrugated board. The batch is therefore formulated within the experimental window rather than by single-point viscosity control alone. Incoming moisture from hygroscopic fillers must be controlled below 0.1 wt% because water vapour injection into a 180 °C melt stream causes visible foam and inconsistent coating weight.

What Happens When SBS 3412P Dispersion Exceeds 6 wt% in Oxidized Bitumen?

High-shear dispersion of SBS 3412P into oxidized bitumen follows a two-phase morphological sequence: the polybutadiene mid-block swells in the maltene fraction, while the polystyrene end blocks remain associated until the mixing temperature exceeds the endblock glass transition. At a mixer set point of 175 °C to 185 °C, addition of 4 wt% to 6 wt% SBS 3412P through a rotor-stator mill at 3,000 rpm typically yields a continuous polymer-rich phase after 45 min to 60 min. Softening point per ASTM D36 rises from a base value of 48 °C to 52 °C to 75 °C to 85 °C; penetration at 25 °C per ASTM D5 decreases to 40 dmm to 50 dmm; elastic recovery per ASTM D6084 Procedure A increases to 60% to 70%. When the addition exceeds 6 wt%, Brookfield viscosity at 180 °C climbs from roughly 1.5 Pa·s to above 4 Pa·s, increasing the risk of phase inversion, pumping difficulty, and storage instability. Low-aromatic bitumen may reject the polymer phase; an aromatic compatibility oil or flux must be pre-blended when the asphaltene-to-maltene ratio is high. Storage stability is assessed by EN 13399 as the difference in softening point after 72 h at 180 °C; values above 5 °C indicate phase separation. Dynamic shear rheometer measurements per ASTM D7175 at 60 °C and 1.6 Hz show increased complex modulus and decreased phase angle after the SBS network forms. Mixing above 195 °C or extended residence beyond 90 min leads to a decrease in elastic recovery and a broadening of the softening point range; the batch must be inert-gas blanketed and sampled every 20 min. Waterproofing membrane and road pavement compounds should be evaluated for low-temperature flexibility by EN 1109 and against the relevant national asphalt specification.

Values in the table are representative industrial ranges for SBS-modified paving-grade bitumen and are not certified lot results for Globalprene® SBS 3412P. Each compound should be qualified against the end-use specification because bitumen source, filler content, and ageing conditions shift the absolute values. Roofing membrane production from the modified bitumen typically uses a saturated polyester or glass-fibre mat impregnated at 1,200 g/m² to 2,500 g/m²; the compound must maintain sufficient low-shear viscosity during calendering to prevent strike-through while retaining elasticity for crack-bridging service at sub-zero temperatures.

When the grade is compounded into injection-moulded thermoplastic rubber sole stock at added oil loadings above 30 phr, the practical working window is bounded by polystyrene endblock reinforcement on one side and plasticizer exudation on the other. A typical formulation uses 100 phr SBS 3412P, 10 phr to 30 phr general-purpose polystyrene, 20 phr to 50 phr naphthenic or paraffinic extender oil, 20 phr to 40 phr calcium carbonate, 0.3 phr to 0.6 phr antioxidant, and 0.2 phr to 0.4 phr UV stabiliser. Mixing is conducted on a co-rotating twin-screw extruder with an L/D ratio of 48:1 and barrel temperatures from 150 °C to 180 °C; melt temperature at the die is maintained below 190 °C. Pellets exposed to relative humidity above 60% should be dried at 60 °C to 70 °C for 2 h to 3 h in a desiccant dryer to reduce surface moisture below 0.05 wt%. Injection moulding is performed at clamp pressures between 150 t and 250 t with a melt cushion of 3 mm to 5 mm and a mould surface temperature of 20 °C to 40 °C. Hardness per ASTM D2240 is typically in the 55–70 Shore A range; tensile strength measured by ISO 37:2017 is 5–10 MPa; elongation at break is 600–900%. DIN 53516 abrasion loss for such compounds generally falls between 150 mm³ and 250 mm³. When added oil loading exceeds 50 phr, oil bloom appears within 21 days at 40 °C in forced-air ageing per ISO 188:2011, and coefficient of friction on dry brushed concrete drops below 0.4 under SATRA TM144. The failure mode observed on production-scale injection machines is cold-weld-line cracking at the mid-foot region; this is corrected by raising melt temperature to no more than 185 °C, reducing injection speed, or adding 5–10 phr polypropylene to the compound. Slow cooling at 60 °C to 80 °C for 8 h increases Shore A hardness by 3–5 points and tensile strength by 1–2 MPa, but compression set per ISO 815-1:2019 worsens by 5–10 percentage points.

The melt rheology of these compounds is shear-sensitive. Capillary rheometry at 190 °C and apparent shear rates of 100 s⁻¹ to 1,000 s⁻¹ is used to set injection pressure; typical apparent viscosity values fall between 150 Pa·s and 400 Pa·s. Mould filling simulations should use Cross-WLF viscosity coefficients rather than single-point melt flow rate because wall slip can occur when the compound contains calcium carbonate above 30 phr. Spiral flow tests on a 2 mm cavity at 180 °C are commonly used as a lot-release check; flow lengths below 600 mm indicate under-plasticised material, while flow lengths above 900 mm may indicate excessive oil or insufficient polystyrene reinforcement. Eyelet tacking, stitching, and direct injection onto EVA foam midsoles require low melt temperature and high injection velocity to prevent substrate collapse. The terminal application is not limited to outsoles: the same compound family is injection-moulded into protective footwear toe caps, heel counters, and soft-touch tool handles when the styrene content and filler package are adjusted.

When SBS 3412P Is Used as an Impact Modifier for Polypropylene at Sub-Zero Service Temperatures

Impact modification of polypropylene homopolymer with 5 wt% to 15 wt% SBS 3412P is carried out on a co-rotating twin-screw extruder with a screw diameter of 40 mm to 75 mm and an L/D ratio of 40:1. The barrel temperatures are set from 180 °C to 200 °C; the polypropylene pellets are fed into the main throat, while SBS 3412P is downstream fed into the melt zone to limit thermal history. Notched Izod impact strength at -20 °C measured by ASTM D256 on 3.2 mm injection-moulded bars increases from below 25 J/m for unmodified homopolymer to 60–120 J/m at 10 wt% SBS; flexural modulus per ASTM D790 drops from approximately 1,500 MPa to 1,000–1,200 MPa. ISO 179-1:2020 Charpy impact values show similar trends, but the absolute gain depends on dispersed rubber particle size and interparticle distance. The unsaturated polybutadiene mid-block limits continuous service temperature to 70 °C; use above this threshold or residence times beyond 3 min at 210 °C causes chain scission, yellowing, and odor development. Published peer-reviewed data for 3412P in impact-modified polypropylene are limited; a compounder should run a three-level design-of-experiments across 5 wt%, 10 wt%, and 15 wt% addition before qualifying an injection-moulded component. Hindered phenol antioxidant at 0.2 wt% and a thioester secondary antioxidant at 0.2 wt% are added to suppress thermo-oxidative degradation during compounding. Copper-containing stabilizers and free-radical generators must be avoided because they accelerate polybutadiene oxidation and crosslinking in the melt line.

The compounded pellets are injection moulded at a melt temperature of 190 °C to 200 °C and a mould surface temperature of 30 °C. Weld-line strength and low-temperature impact are strongly influenced by cooling rate; rapid cooling produces smaller polypropylene spherulites and finer SBS dispersion, while slow cooling increases modulus but reduces impact retention at -20 °C. Batch-to-batch viscosity variation in the supplied SBS may shift the dispersed phase morphology; capillary rheometry at 190 °C and 1,000 s⁻¹ should be used to normalize the blend ratio before production lot release.

Solvent-borne contact adhesive formulations based on SBS 3412P are produced by dissolving the polymer in a mixed aromatic/aliphatic solvent system such as 60 wt% toluene, 20 wt% n-hexane, and 20 wt% methyl ethyl ketone. Dissolution is carried out in a closed, explosion-proof dissolver at 1,500 rpm for 2 h to 4 h at 25 °C until the solution viscosity measured by Brookfield RV at 20 rpm is between 1,000 mPa·s and 3,000 mPa·s. Solids content is controlled at 25 wt% to 35 wt%; below 25 wt% the wet bond line may squeeze out on porous substrates, and above 35 wt% the adhesive may string or cobweb during roller coating. T-peel adhesion is tested per ASTM D903-98 on canvas-to-canvas substrates after 24 h conditioning at 23 °C and 50% RH; values from 3 kN/m to 6 kN/m are typical for footwear assembly. Open time is measured as the interval between coating and loss of tack; with the above solvent ratio, open time is 15 min to 25 min at 25 °C. The solvent ratio adjusts both drying rate and the solvation balance: toluene and methyl ethyl ketone solvate the styrene end blocks, while n-hexane swells the butadiene mid-block and controls viscosity. Water content in the solvent system must remain below 0.1 wt%; higher moisture produces hazy solutions and reduces contact bond strength on PVC and EVA foam. For food-contact packaging end uses, the formulated adhesive must be reviewed under 21 CFR 175.105 and EU Regulation 10/2011 migration requirements; the raw polymer lot does not independently establish compliance.

The contact adhesive is applied by brush, roller, or spray gun to both substrates and dried for 10 min to 15 min before bonding. Maximum bond strength is obtained when the solvent retention level at the bond line is below 5 wt%; residual solvent above this level causes bubbling and reduces heat resistance. For automatic footwear lines, twin-head spray systems with exhaust air velocities of 0.5 m/s to 1.0 m/s are used to maintain a constant flash-off profile. The compound is not suitable for immersion in polar solvents after drying because the styrene domains can be attacked by ketones; resistance to aliphatic hydrocarbons is moderate. Isocyanate crosslinkers are generally not required; peroxide crosslinking is possible but increases viscosity and shortens pot life, and must be evaluated by gel content measurement. For metal bonding, a chlorinated-polyolefin primer is applied at 3 g/m² to 5 g/m² before the SBS contact adhesive to improve peel strength under humid ageing. Published data for this specific product in chlorinated-polyolefin adhesion on EVA midsole foam is limited.