Bitumen modifiers

Material Wizard is a Ukrainian distributor of SBS rubbers from three production sites in China and the manufacturer of its own trademark Exaflex^® SBS (Derazhnia, Khmelnytskyi region). We supply styrene-butadiene-styrene block copolymers for the production of polymer-modified bitumen (PMB), bitumen-polymer roll materials, road sealants, hot-melt adhesives and polyolefin modification. All products are shipped with a batch certificate of analysis (CoA) and comply with DSTU EN 14023:2023 (PMB framework specification, IDT with EN 14023:2010) and DSTU B V.2.7-135:2014 (road polymer-modified bitumen).

What is an SBS bitumen modifier

Styrene-butadiene-styrene (SBS) is a thermoplastic elastomer whose molecular structure connects polystyrene blocks (hard phase) with a polybutadiene block (elastomeric phase). In bitumen, the polystyrene domains form a physical crosslinking network without chemical vulcanization — this increases the cohesion, softening point, elastic recovery and rutting resistance of the finished binder. Unlike SBR/NR-based rubbers, SBS requires no vulcanization and is processed on standard hot-mix equipment for blending with bitumen.

Under EN 14023, SBS modification provides elastic recovery of ≥ 60 % in the finished PMB — the key marker of quality modification, unattainable with EVA, APP and most plastomeric additives.

PMB classes under EN 14023 / DSTU EN 14023:2023

The standard classifies polymer-modified bitumens by penetration at 25 °C and minimum softening point (Ring and Ball). There are 15 classes in total. The most common on the Ukrainian market:

All classes require testing of elastic recovery (EN 13398), storage stability (EN 13399, Δ T_soft ≤ 5 °C over 72 h at 180 °C), Fraass breaking point (EN 12593) and cohesion (EN 13589 / EN 13703).

Linear SBS vs radial SBS — which to choose for PMB

The architecture of the macromolecule fundamentally affects how SBS behaves in bitumen. A brief comparison matrix:

Conclusion: for typical Ukrainian road bitumens (BND 50/70, BND 70/100) and most PMB classes, linear SBS is the optimal choice. Radial SBS is used selectively — where maximum rutting resistance is required (airfield slabs, bridges).

In-house production: Exaflex^® SBS 7090

Exaflex^® SBS 7090 is the flagship of Material Wizard's own trademark. A linear block copolymer with a nominal butadiene/styrene ratio of ≈ 70/30, designed specifically for PMB applications. Key characteristics:

• Bound styrene: 30 ± 2 wt%
• Tensile strength: ≥ 16 MPa (ISO 37)
• Elongation at break: ≥ 800 % (ISO 37)
• Hardness: 68–72 Shore A (ISO 868)
• MFR (200 °C / 5 kg): 0,1–0,5 g/10 min (ISO 1133)
• Residual volatiles: ≤ 0,7 wt%
• Architecture: linear (S-B-S)
• Supply form: porous pellets, 25 kg bags, EUR pallets of 1000–1100 kg

Exaflex^® SBS 7090 produces PMB of classes 25/55-55, 45/80-65 and 75/130-65 (per EN 14023) at dosages of 3,0–6,0 wt% on a BND 50/70 or BND 70/100 base bitumen. The full TDS, high shear mill mixing regimes and target properties of the finished binder are available on the Exaflex^® SBS 7090 product page.

How SBS is incorporated into bitumen (high shear mill)

PMB quality is 60 % determined by the mixing technology, not just by the SBS grade. The standard industrial procedure:

1. Heat the base bitumen to 175–185 °C with continuous stirring.
2. Feed the SBS through a doser at a rate matched to the mill throughput.
3. High-shear dispersion on a colloid mill (high shear mill, 4 000–6 000 rpm) for 25–45 min until the SBS particle size is ≤ 5 µm. Control — fluorescence microscopy.
4. Digestion for 1,5–3 h at 175–185 °C with low-speed stirring — for complete swelling of the SBS in the maltene phase of the bitumen.
5. Stabilization (if required) — adding a reactive stabilizer: 105 % phosphoric acid (0,5–1,5 wt% of SBS) or elemental sulfur (0,05–0,15 wt% of PMB).
6. Laboratory control: penetration (EN 1426), T_soft (EN 1427), elastic recovery (EN 13398, ≥ 60 %), storage stability (EN 13399, Δ T_soft ≤ 5 °C after 72 h at 180 °C), Fraass breaking point (EN 12593).

Failure to follow the procedure at any stage (especially insufficient dispersion) leads to SBS phase segregation in the storage tank and loss of modification within 24–72 h.

Logistics and supply volumes

Supply from the warehouse in Derazhnia (Khmelnytskyi region) is palletized — FCA Derazhnia or delivered across Ukraine by our own transport. Minimum lot — 1 pallet (1 000 kg). Standard full-truck lot — 20 tonnes. For large PMB producers we offer contract supply with a quarterly schedule and fixed pricing. In-house production of Exaflex^® SBS 7090 is additional insurance against import market fluctuations and currency risks.

To request a commercial offer, a batch certificate of analysis, samples (1–5 kg) or technical advice on selecting an SBS for your base bitumen, call +38 050 323-23-21 or write to [email protected].

Questions and answers — for polymer-modified bitumen producers

Which SBS should I choose for PMB 45/80-65?

The most popular class on the Ukrainian market. The optimal choice is a linear SBS with ~30 % styrene content. On a BND 70/100 base, a dosage of 3,5–4,5 wt% gives a T_soft of 65–72 °C and elastic recovery of ≥ 75 %. Suitable grades: Exaflex^® SBS 7090, Kraton^® D1101, EN CHUAN 701 S, Globalprene 3710. Radial SBS grades are excessive in viscosity for 45/80-65.

How does linear SBS differ from radial SBS?

Linear SBS (S-B-S) has a molecular weight of 120–200 thousand g/mol — it is more compatible with bitumen, disperses in 30–45 min on a high shear mill and gives a stable PMB under typical storage conditions. Radial (star-shaped) SBS has 250–500 thousand g/mol — coarser particles and a higher modulus of the finished binder, but it needs longer mixing, segregates more often and gives higher PMB viscosity at 135 °C. Radial SBS is used selectively — for very stiff pavements (PMB 10/40-65), airfields and bridges.

How much SBS should be added to BND 70/100 bitumen?

It depends on the target PMB class:

• PMB 45/80-65 — 3,0–4,0 wt% SBS
• PMB 25/55-65 — 4,0–5,0 wt% SBS
• PMB 25/55-75 — 5,5–6,5 wt% SBS

Exceeding 7 % leads to a sharp rise in viscosity, complicates asphalt compaction and increases cost with only a small gain in T_soft. Fine-tuning this balance requires laboratory trials.

How can SBS phase segregation in the finished PMB be avoided?

Four key factors: (1) choose a linear SBS rather than a radial one; (2) perform full dispersion on a high shear mill down to a particle size of ≤ 5 µm; (3) allow digestion for 1,5–3 h at 175–185 °C; (4) add a reactive stabilizer — 105 % phosphoric acid (0,5–1,5 wt% of SBS) or elemental sulfur (0,05–0,15 wt% of PMB mass). Control — the EN 13399 test: the difference in T_soft between the top and bottom of the tube after 72 h at 180 °C must not exceed 5 °C.

Can SBS be purchased in lots smaller than 1 tonne?

Yes. The minimum order lot of Exaflex^® SBS 7090 is 1 pallet (1 000 kg, 40 bags of 25 kg). For pilot trials and laboratory development we provide 1–5 kg samples free of charge (logistics paid by the customer). For imported brands (Kraton, Kumho, Globalprene) the minimum lot may vary — please check when enquiring.

Does Exaflex^® SBS 7090 comply with DSTU EN 14023:2023 and DSTU B V.2.7-135:2014?

Exaflex^® SBS 7090 is a raw material (a polymer modifier), while DSTU EN 14023:2023 and DSTU B V.2.7-135:2014 regulate the finished PMB. The correct wording is therefore: Exaflex^® SBS 7090 makes it possible to produce PMB that meets the requirements of both standards, provided the process procedure is followed and a base bitumen of proper quality is used. Every batch is accompanied by a certificate of analysis (CoA) covering all parameters that affect certification of the finished binder.

What are the mixing regimes for Exaflex^® SBS 7090 with bitumen?

Standard procedure: heat the bitumen to 175–185 °C, feed the SBS through a doser, disperse on a high shear mill for 25–45 min (4 000–6 000 rpm) to a particle size of ≤ 5 µm, then digest for 1,5–3 h at 175–185 °C with low-speed stirring. Temperatures above 190 °C are not recommended — thermo-oxidative degradation of the SBS begins.

Which is better for PMB production: SBS pellets or powder?

For industrial plants with a high shear mill, pellets are better: better flowability, more accurate dosing, lower risk of dusting and self-ignition. SBS powder may dissolve faster, but it requires closed feeding systems due to the dust formation risk. Exaflex^® SBS 7090 is supplied as porous pellets with a process dusting agent — the optimal form for most asphalt plants.

What is the difference between SBS and EVA bitumen modifiers?

SBS is an elastomer: it provides elastic (recoverable) deformation and high elastic recovery (≥ 60 % per EN 13398). It suits cold and temperate climates, with high crack resistance and fatigue resistance. EVA (ethylene-vinyl acetate) is a plastomer: it deforms plastically (irreversibly), offers better rutting resistance in hot weather, but performs worse at low temperatures. SBS is the standard for Ukrainian highways; EVA is used selectively in hot climates (southern Ukraine, airfields).

Is anything else needed in a PMB formulation besides SBS?

Often, yes. In addition to the SBS itself, formulations use: (a) reactive compatibility stabilizers — 105 % phosphoric acid or elemental sulfur; (b) adhesion promoters (surfactants, amines) — to improve bonding to the aggregate; (c) antioxidants — for thermal stability of the PMB during storage. Formulation development is an individual task for each bitumen + SBS pair. Our laboratory helps partners through this stage.

How can I verify that the produced PMB meets the declared class?

Mandatory laboratory control under EN 14023 / DSTU EN 14023:2023:

• Penetration at 25 °C (EN 1426) — within the class range
• Ring and Ball softening point (EN 1427) — ≥ the class minimum
• Elastic recovery at 25 °C (EN 13398) — ≥ 60 % for SBS-PMB
• Storage stability (EN 13399) — Δ T_soft ≤ 5 °C after 72 h at 180 °C
• Fraass breaking point (EN 12593) — for cold climates
• Cohesion (EN 13589 — force ductility method, or EN 13703 — pendulum)

Without these tests, a declared PMB class is not credible.

How long does delivery of Exaflex^® SBS 7090 take?

From the warehouse in Derazhnia: typically 1–3 business days across Ukraine (a 20-tonne truck or a 1 000 kg pallet). For regular PMB producers we offer quarterly contracts with fixed pricing and volume reservation — this minimizes currency risk and guarantees availability in season. Enquiries: +38 050 323-23-21 or [email protected].