Lubricant Additives - Ashless Dispersants Series: Borated PIB Bis-Succinimide combines the two key upgrades from the dispersant series into a single molecule: the dual-PIB shear-stable backbone of bis-succinimide + the cyclic borate ester multifunctionality of boronation. The boron atom in this grade forms a cyclic borate ester chelate ring bridging two succinic acid residues from two separate PIBSA units - a more thermally and hydrolytically stable borate structure than the linear borate ester of borated mono-PIBSI. The result: maximum combination of shear stability, dispersancy, boron-derived TBN, antioxidant activity, and anti-wear performance. Zero S/A, zero S, zero P. Sinolook supplies: PIBSI · Bis · Poly · Borated PIBSI · Borated PIB Bis-Succinimide · Boron-Phosphated PIB Bis-Succinimide · Low Viscosity Dispersant.
Lubricant Additive · Borated Ashless Dispersant · Dual PIB Shear-Stable · Cyclic Borate Ester · TBN + AO + Anti-Wear · Zero S/A · HDEO · ATF · PCMO Long-Drain
Borated PIB Bis-Succinimide
Borated Polyisobutylene Bis-Succinimide / N 1.5–3.0 wt% · B 0.3–1.0 wt% / Cyclic Borate Ester Architecture · Shear-Stable · Multifunctional · HDEO EGR · ATF/CVT · Marine
| Chemical Class | Borated polyisobutylene bis-succinimide - produced by double imidation of two PIBSA units with a polyamine chain (standard bis-succinimide synthesis) followed by controlled boronation; the boronation of the bis-succinimide backbone preferentially forms a cyclic borate ester chelate ring bridging two carboxylate/hydroxyl groups from the two adjacent succinic acid residues - a five- or six-membered cyclic B–O–C ring that is more thermally and hydrolytically stable than the linear borate ester formed in borated mono-PIBSI; two PIB tails flank the polyamine core; NO Ca/Mg/Zn / NO sulphur / NO phosphorus |
| Structure (image) | Two parallel chains in image: upper R–CH₂–C(=O)–CH₂–CH₂–C(=O)–O– and lower R–CH₂–C(=O)–CH₂–CH₂–R", each with C=O groups. Central B₂ (boron atom, green) bridges the two chains via two borate ester oxygen bonds (–O–B–O–), forming the cyclic chelate ring. 3D model: green = B, blue = N (ring nitrogens), red = O (borate ester + carbonyl oxygens), grey/white = C/H. The symmetric dumbbell architecture (two PIB tails + central boron chelate cluster) is clearly visible. |
| ★ Structural Advantage | ★ Cyclic borate ester - more stable than linear (Borated PIBSI) Dual PIB anchor - superior shear stability Highest N+B combination in the series |
| GHS Hazards | Combustible liquid FP ≥190°C H315/H319 skin/eye irritant |
What Is Borated PIB Bis-Succinimide?
Borated PIB Bis-Succinimide is the premium apex of the borated dispersant sub-series - combining the bis-succinimide's shear-stable dual-PIB architecture with boronation to create a molecule that delivers five simultaneous performance functions: bulk-phase soot/sludge dispersancy, shear-stable molecular integrity, boron-derived TBN, antioxidant radical-chain termination, and boundary anti-wear/friction reduction. The defining structural feature distinguishing it from borated mono-PIBSI is the cyclic borate ester chelate ring: when boron bridges two carboxylate/hydroxyl groups from the two adjacent succinic acid residues of the bis-succinimide backbone, it forms a thermodynamically more stable five- or six-membered cyclic borate ring, rather than the linear (open-chain) borate ester formed when boron is grafted onto the single succinic residue of a mono-succinimide.
Cyclic borate esters are well-established in boron chemistry to be more hydrolytically and thermally stable than linear borate esters - the thermodynamic advantage of ring closure (chelate effect) reduces the Gibbs free energy of the borate ester structure, making it significantly more resistant to hydrolysis by moisture and to thermal decomposition at elevated temperatures. This means borated PIB bis-succinimide retains its B% and TBN content longer in service (both in the neat additive and in the finished oil under elevated crankcase temperatures) compared to borated mono-PIBSI, and is less sensitive to moisture exposure during storage.
| Property | Bis-Succinimide (non-borated) | Borated PIBSI (mono) | Borated PIB Bis-Succinimide |
|---|---|---|---|
| PIB tails | 2 | 1 | ★ 2 (shear-stable) |
| Borate ester type | None | Linear borate ester | ★ Cyclic chelate ring (more stable) |
| Nitrogen content | 1.5–3.5% | 1.5–2.5% | ★ 1.5–3.0% (high N+B combo) |
| Boron content | 0 | 0.5–1.5% | 0.3–1.0% (cyclic, stable) |
| Borate hydrolysis resistance | N/A | Moderate (linear ester) | ★ Superior (cyclic chelate) |
| TBN | ~0–5 mgKOH/g | 20–40 mgKOH/g | 10–30 mgKOH/g (sustained longer in service) |
| Shear stability | Superior (dual anchor) | Standard (single anchor) | ★ Superior (dual anchor + cyclic B) |
| Viscosity @100°C | 100–600 cSt | 100–300 cSt | 150–400 cSt |
| Ash / S / P | 0/0/0 | ~0/~0/0 | ~0/~0/0 |
When to choose Borated Bis vs Borated PIBSI: Choose Borated PIB Bis-Succinimide when shear stability is a critical formulation requirement (ATF, CVT, HDEO long-drain, high-shear gear oil) - the dual PIB anchor prevents dispersant degradation under high mechanical stress. The cyclic borate ester also provides better boron retention over the drain interval than linear-ester borated PIBSI. Choose Borated PIBSI when cost optimisation is the primary driver and shear stress is moderate (standard PCMO, industrial applications, fuel additives).
Technical Specification
Linear borate ester (Borated PIBSI):
R–O–B(OH)₂ or R–O–B(–OR')₂ - open chain structure; thermodynamic stability relies on B–O bond strength alone; susceptible to step-wise hydrolysis in moist environments: first B–O–C bond cleaved → mono-hydrolysis product (still partially active); second cleavage → B(OH)₃ fully released (loss of TBN and AO function); relatively sensitive to moisture in drum storage and in service when water contamination occurs.
★ Cyclic borate ester (Borated PIB Bis-Succinimide):
Cyclic B–O–C–C–O ring (5- or 6-membered chelate) - thermodynamic ring stability (chelate effect) adds ΔΔG ≈ −5 to −10 kJ/mol to each B–O bond compared to the equivalent linear ester; both B–O bonds must be simultaneously cleaved for hydrolysis to proceed (analogous to the chelate effect in coordination chemistry); statistically far less probable under normal moisture exposure; maintains B%, TBN, and AO activity over longer service periods; better performance in high-temperature crankcase conditions where base oil moisture from combustion blow-by is present.
Practical consequence: In a 15W-40 HDEO used for 60,000 km, the borated dispersant in the oil is exposed to approximately 1,500–3,000 hours of crankcase temperatures (85–130°C) with intermittent moisture from blow-by condensation. End-of-drain B% retention in borated bis-succinimide formulations is typically 15–25% higher than in equivalent borated mono-PIBSI formulations - directly translating to better TBN maintenance and sustained AO activity throughout the drain interval.
| Parameter | Specification | Test Method | Note |
|---|---|---|---|
| Appearance | Clear brown viscous liquid | Visual | Clear brown (cyclic borate ester reduces polarity-driven self-aggregation vs non-borated grades); warm to 40–60°C for handling; semi-viscous at ambient |
| Nitrogen Content | 1.5–3.0 wt% | ASTM D5291/D3228 | Higher than Borated PIBSI (1.5–2.5%) due to bis backbone retaining more internal –NH groups even after cyclic boronation; grade-specific on COA |
| Boron Content ★ | 0.3–1.0 wt% | ICP-OES | Cyclic form - confirm on COA; stable in storage and in service; lower absolute B% than Borated PIBSI but superior retention over drain interval |
| TBN (D2896) ★ | 10–30 mgKOH/g | ASTM D2896 | Boron Lewis basicity TBN; at 6 wt% treat → +0.6–1.8 mgKOH/g to finished oil TBN at zero S/A; better TBN retention at end-of-drain than Borated PIBSI |
| Flash Point (COC) | ≥ 190°C | ASTM D92 | Higher than Borated PIBSI (≥180°C); suitable for high-temperature HDEO and marine applications |
| Kinematic Viscosity @100°C | 150–400 cSt | ASTM D445 | Include in SAE viscosity grade calculation; manageable at 4–10 wt% treat; warm to 40–60°C before blending |
| Density @20°C | 0.95–1.05 g/cm³ | ASTM D4052 | Higher than non-borated bis-succinimide (~0.90–0.95 g/cm³); use for mass-to-volume treat rate conversion in volumetric blending operations |
| Sulphated Ash / S / P | ~0 / ~0 / 0 wt% | D874 / D2622 / D4047 | No conventional S/A; trace B₂O₃ volatile at D874 temperature; verify in ACEA C1/C5 if applicable; DPF/GPF compatible |
| Packaging | 180 kg drum · 900–1000 L IBC · Flexitank | - | Store 0–45°C sealed; cyclic borate ester more moisture-stable than linear ester; 24-month shelf life; KFT water ≤0.15% on receipt (slightly relaxed vs linear borate ester ≤0.10%) |
Performance Profile
Shear Stability - Dual PIB Anchor + Cyclic Boron Ring
The dual-PIB backbone provides the same fundamental shear stability advantage over mono-succinimide as non-borated bis-succinimide - two simultaneous bond cleavages would be required to remove the polar head group from the molecule (statistically improbable under normal engine shear). The additional cyclic borate ester chelate ring introduces a second source of structural rigidity: the cyclic B–O–C ring constrains the local conformation of the polar head group, reducing the rotational freedom available for bond alignment under shear stress. In CEC L-45 shear stability testing (Kurt-Orbahn method, 30 and 60 passes), borated PIB bis-succinimide formulations show marginally better dispersancy retention vs non-borated bis-succinimide - consistent with the cyclic borate ring's conformational constraint. This makes it the preferred dispersant grade for ATF and CVT applications where both shear stability and boron's friction-modifying contribution are simultaneously required.
In-Service Boron Retention - Cyclic vs Linear Borate Ester
In a long-drain HDEO (60,000–100,000 km service, crankcase temperature 85–130°C with intermittent water from combustion blow-by), the borated dispersant is exposed to conditions that progressively hydrolyse the borate ester linkage. Linear borate esters (Borated PIBSI) hydrolyse in two sequential steps - partial hydrolysis first reduces TBN by ~50% before full loss, meaning there is a period of rapidly declining boron function mid-drain. Cyclic borate esters require simultaneous rupture of two B–O bonds - an entropically and enthalpically disfavoured event - so B% remains substantially intact until near end-of-drain before any significant hydrolytic loss. The practical result is that the AO function, anti-wear boundary film, and supplemental TBN from the borated dispersant are better maintained throughout the drain interval, particularly in the second half of long-drain service where acid challenge from NOₓ and combustion products is at its maximum.
High-Soot EGR Dispersancy with Sustained AO Activity
Modern heavy-duty diesel engines with high EGR rates (up to 25%) generate soot at 2–6 wt% concentration in the crankcase oil by mid-drain interval, while simultaneously raising crankcase oxidation stress through NOₓ blow-by. Borated PIB Bis-Succinimide addresses both challenges simultaneously: the bis backbone's dual-PIB steric barrier provides superior soot-holding at high soot concentrations (vs borated PIBSI's single-anchor), while the sustained cyclic borate ester AO function continues to contribute B–O–N radical chain termination throughout the drain interval even as linear-ester borated dispersants are losing their boron function through hydrolysis. In API CK-4 Mack T-13 soot viscosity testing and ASTM Sequence IIIGH oxidation stability, formulations using borated bis-succinimide show better end-of-drain performance than equivalent borated PIBSI formulations at the same treat rate.
ATF / CVT - Shear Stability + Boron Friction Modification
In automatic transmission fluids (ATF Dexron VI, ZF LifeGuard 8) and CVT fluids (NS-2/NS-3), two simultaneous requirements are difficult to satisfy with a single dispersant: (1) shear stability over the transmission's 100,000–200,000 km service interval; (2) friction control - the dispersant must not interfere with the friction modifier system that governs lock-up clutch behaviour (smoothness, stick-slip torque control). Borated PIB Bis-Succinimide uniquely satisfies both: the dual-PIB anchor provides the superior shear stability needed for ATF service, while the boron centre - forming a B–O–N tribological film on the clutch plate surfaces - contributes a mild friction-modifying effect that supplements the primary friction modifier (e.g. GMO, fatty acid amide) without disrupting the friction coefficient profile. This combination of dispersancy + shear stability + boron friction modification in a single ashless molecule makes borated PIB bis-succinimide a standard component in premium ATF formulations.
Applications & Formulation Guidance
1. HDEO - Premier Long-Drain EGR-Duty Dispersant Package
In premium HDEO formulations for extreme long-drain service (100,000 km OEM approvals, Euro VI emission compliance), borated PIB bis-succinimide provides the highest combined performance per treat unit: dispersancy equivalent to non-borated bis-succinimide + sustained TBN (cyclic borate ester maintained better at end-of-drain) + sustained AO activity + anti-wear supplementation. The standard blending approach: use borated PIB bis-succinimide as the primary dispersant (5–8 wt%) replacing a blend of non-borated bis-succinimide + borated mono-PIBSI, thereby consolidating dispersancy, TBN supplement, and AO supplement into a single component - reducing the additive package component count and improving formulation stability.
2. ATF & CVT - Shear-Stable Dispersant with Boron Friction Control
The combination of dual-PIB shear stability and boron friction modification makes borated PIB bis-succinimide uniquely suited to ATF and CVT fluid formulations. At 3–6 wt% treat, it provides: (1) shear-stable dispersancy over 150,000–200,000 km transmission service; (2) varnish and sludge prevention in the valve body and clutch pack; (3) mild boron friction modification on the clutch plate surface that is compatible with (and complementary to) the primary GMO/fatty acid amide friction modifier system. For premium ATF formulations targeting Dexron VI lip-seal friction (B coefficient 0.110–0.115) and lock-up clutch smoothness, borated PIB bis-succinimide's boron tribological contribution has been specifically validated as non-disruptive to the ATF friction profile in SAE #2 friction test - a critical qualification requirement.
3. Natural Gas Engine Oil - Sustained AO + NOₓ Resistance
In gas engine oils with 1,500–2,000 hour drain intervals, the cyclic borate ester's superior hydrolysis resistance translates to better AO function retention across the full drain interval - particularly important in the second 1,000 hours of service where NOₓ-induced nitration stress is at its maximum and the primary AO system (DBPC, aminic AO) is partially depleted. The borated bis-succinimide's sustained B–O–N radical termination supplements the depleted primary AO, extending the oil's oxidative stability reserve into the critical later stages of the drain interval. Combined with Ca salicylate (zero S, excellent NOₓ-nitrate resistance) and standard aminic/phenolic AO, borated PIB bis-succinimide at 4–6 wt% forms the core of modern premium gas engine oil dispersant-AO packages for MTU Type 3, GE Jenbacher, and Caterpillar G3500 series engines.
4. Marine TPEO, Industrial Gear & Compressor - Long-Service Boron Retention
In industrial lubricants with multi-year or multi-thousand-hour service intervals - where moisture infiltration from the environment (marine bilge, outdoor gear sumps, compressed air systems) is a persistent challenge - the cyclic borate ester's superior hydrolysis resistance is a decisive advantage over linear-ester borated mono-PIBSI. For marine TPEO formulations (BN 25–40 on VLSFO, 1,000–3,000 hour TPEO drain), borated PIB bis-succinimide maintains its boron-derived TBN supplementation and AO activity substantially intact over the drain interval, unlike borated PIBSI which progressively loses B% through moisture hydrolysis in the marine environment. For industrial gear oils (ISO 220–460, 3–5 year service) and compressor oils (4,000–8,000 hour change interval), the cyclic borate ester ensures the antioxidant and anti-wear functions are sustained throughout the entire multi-year service period.
Frequently Asked Questions
Q: Borated PIB Bis-Succinimide has lower absolute B% (0.3–1.0%) than Borated PIBSI (0.5–1.5%) - why is it considered the superior borated grade?
This is the key question when comparing the two borated grades. The answer lies in the distinction between initial B% (fresh additive, as-received) and effective B% over the drain interval. Borated PIBSI starts with higher initial B% (0.5–1.5%) but loses a significant fraction of it through progressive hydrolysis of the linear borate ester over the drain interval - particularly in long-drain, high-temperature, moisture-contaminated service conditions. Borated PIB Bis-Succinimide starts with lower initial B% (0.3–1.0%) but retains substantially more of it at end-of-drain because the cyclic chelate borate ring is much more resistant to hydrolysis. In a 100,000 km HDEO drain simulation, the end-of-drain effective B% of borated bis-succinimide may be 15–25% higher than that of borated PIBSI that started with twice the initial B%. Additionally, borated bis-succinimide simultaneously provides superior shear stability (dual-PIB anchor) - a capability that borated PIBSI cannot match regardless of B%. The combination of better boron retention + superior shear stability makes borated bis-succinimide the premium choice for demanding long-service applications despite its lower initial B%.
Q: Why is the density specification (0.95–1.05 g/cm³) important for blending operations, and how does it compare to standard bis-succinimide?
The density specification matters for blending operations because lubricant additive treat rates are typically specified in wt% (mass-based, for SAPS and N% calculations) but blending equipment often measures in volume (flow meters, volumetric tanks). Borated PIB Bis-Succinimide at 0.95–1.05 g/cm³ is notably denser than standard non-borated bis-succinimide (typically 0.88–0.95 g/cm³) due to the borate ester groups' higher polarity and the oxygen atoms they contribute to the molecular structure. At a target of 6 wt% treat in a 15W-40 HDEO (final density ~0.872 g/cm³), the volumetric equivalent of 6 wt% borated bis-succinimide is approximately 6% × (0.872/1.00) ≈ 5.23 vol% - versus 6% × (0.872/0.91) ≈ 5.75 vol% for standard bis-succinimide. Blenders must use the measured product density from the COA to convert between mass and volume treat rates - do not assume the same volumetric treat rate as non-borated grades without recalculating.
Q: Can Borated PIB Bis-Succinimide be used as the sole dispersant in an HDEO additive package, or must it be blended with non-borated dispersants?
It can be used as the sole dispersant grade, and increasingly is in premium long-drain HDEO packages where its combined dispersancy + shear stability + boron multifunctionality justifies the cost premium over non-borated grades. However, the decision depends on balancing four factors: (1) Cost: borated bis-succinimide costs more per kg than non-borated mono-PIBSI or bis-succinimide - for standard-drain HDEO (15,000–30,000 km), cost-optimised formulations may use 70–80% non-borated bis-succinimide + 20–30% borated bis-succinimide to capture most of the boron benefits at lower cost; (2) Sequence VH sludge: non-borated mono-PIBSI's free –NH₂ terminal groups provide marginally better Sequence VH sludge performance than bis structures - in formulations where Sequence VH is the binding constraint, a 20–30% mono-PIBSI addition to a borated bis-succinimide package may be beneficial; (3) Long-drain EGR-heavy HDEO: here, borated bis-succinimide as sole dispersant (5–8 wt%) is the optimal choice - maximum shear stability and sustained boron function outweigh any minor Sequence VH disadvantage; (4) ATF/CVT: borated bis-succinimide as sole dispersant at 3–5 wt% is standard practice in premium ATF formulations.
Technical & Regulatory References
D5291/D3228 (N%) · ICP-OES (B%) · D2896 (TBN 10–30) · D4052 (density) · D445 (viscosity 150–400 cSt) · D92 (FP ≥190°C) · D874 (S/A ~0) · D2622 (S ~0) · D4047 (P=0) · KFT (water ≤0.15%) · D7843 (blotter soot) · CEC L-45 / ASTM D6278 (shear stability - bis-preferred) · Mack T-12/T-13 · ASTM Sequence VH / IIIGH · SAE #2 friction (ATF lock-up clutch) · CEC L-51 (gear anti-wear)
API SP/SN+ · API CK-4/FA-4 · ACEA A3/B4 · C2/C3 · E6/E9 · VW 504/507 · BMW LL-04/17FE · GM Dexron VI (ATF) · ZF LifeGuard 8 (ATF) · Toyota WS/T-IV (CVT) · Allison C4 · MTU Type 3 · GE Jenbacher · Caterpillar G3500 · Marine TPEO ISO 8217 BN 25–40 · DIN 51517 CLP (industrial gear)
REACH registered · TSCA listed · No SVHC · Zero conventional S/A (D874) · Zero S · Zero P · DPF/GPF/SCR compatible · GHS SDS available · Boron SVHC note: boric acid H₃BO₃ is SVHC but covalently bonded cyclic borate ester polymer is exempt from boric acid SVHC restriction
PIBSI · Bis-Succinimide · Poly-Succinimide · Borated PIBSI · Borated PIB Bis-Succinimide ✅ · Boron-Phosphated PIB Bis-Succinimide (next) · Low Viscosity Dispersant
Borated PIB Bis-Succinimide · N 1.5–3.0% · B 0.3–1.0% (Cyclic) · TBN 10–30 mgKOH/g · FP ≥190°C · Zero S/A · Shear-Stable · COA/TDS/SDS
Request Pricing, TDS & Qualification Sample
Specify target N% (1.5–3.0%) and B% (0.3–1.0%), application (HDEO long-drain · ATF/CVT · gas engine · marine TPEO · industrial), volume, and destination port. Full COA including B% (ICP-OES) and TBN (D2896), TDS, and SDS within 12 hours. Qualification samples (1–5 kg) available.
Ashless Dispersants: PIBSI ✅ · Bis ✅ · Poly ✅ · Borated PIBSI ✅ · Borated Bis-Succinimide ✅ · Boron-Phosphated Bis-Succinimide (next) · Low Viscosity Dispersant
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