Technical Specifications
| Parameter | Value | Test Method |
|---|---|---|
| Chemical name | Di(dioctyl pyrophosphato) Oxoethylene Titanate | — |
| CAS number | 65460-52-8 | — |
| Appearance | Light yellow to amber liquid | Visual |
| Active content | ≥95% | GC |
| Density (25°C) | 0.96–1.00 g/cm³ | ASTM D792 |
| Viscosity (25°C) | 80–200 mPa·s | ASTM D7042 |
| Flash point (PMCC) | >110°C | ASTM D93 |
| Titanium content | ~7.5 wt% | ICP-OES |
| Recommended dosage | 0.5–2.0% on filler weight | — |
| Max processing temp. | 220°C continuous / 250°C short-term | — |
| Shelf life | 24 months (sealed, below 30°C) | — |
Coordinate-Type Mechanism
KR-26S bonds through coordinate chemistry rather than hydrolytic displacement, making it effective on low-hydroxyl fillers (CaCO₃, talc, BaSO₄) where monoalkoxy grades like KR-9S underperform. The two dioctyl pyrophosphato groups orient toward the polymer matrix, reducing melt viscosity and suppressing agglomeration.
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Performance in High-Filler-Loading Thermoplastics
At 70 wt% CaCO₃ in polypropylene, KR-26S delivers 35–45% reduction in melt flow index drift versus untreated controls, with tensile elongation improving from below 15% to above 40%. For moisture-sensitive applications, compare with KR-138S.
Processing Conditions
Pre-coat filler for best results: dilute KR-26S to 10–20% in mineral spirits, spray onto filler, dry at 80°C for 30 minutes. Dosage 0.5–1.5% for carbonates; 1.5–2.0% for high-BET silicates. Do not exceed 250°C barrel temperature.
Polymer Compatibility
Formulated for PP, PE, EVA, TPE, and nylon 6 at filler loadings up to 40 wt%. Performs poorly in PVC or polyester without compatibilizer. Primary end-uses: automotive interior PP/talc, halogen-free FR cable jacketing (PE/CaCO₃ at 60–70 wt%), and rubber with mineral fillers.
Frequently Asked Questions
+Q: What makes KR-26S different from single-alkoxy titanates like KR-9S?
A: KR-26S bonds via coordinate chemistry rather than hydrolytic alkoxy displacement, making it effective on low-hydroxyl fillers where monoalkoxy grades show limited activity. This accounts for superior performance above 50 wt% filler loading.
+Q: What filler loading levels can KR-26S support in polypropylene?
A: Up to 70–75 wt% CaCO₃ while maintaining processable viscosity and elongation above 30%. Without coupling treatment, compounds above 55 wt% typically show melt fracture and brittle failure.
+Q: Is KR-26S thermally stable for engineering thermoplastics?
A: Rated for 220°C continuous, 250°C short-term — covering PP and PE compounding. Above 250°C the pyrophosphato groups dissociate. For nylon or ABS above 230°C, evaluate KR-138S.
+Q: Can KR-26S be used in halogen-free flame-retardant cable compounds?
A: Yes — widely used in HFFR cable jacketing with 60–70 wt% ATH or MgOH in PE/EVA. Improves particle dispersion, reduces viscosity, and contributes marginally to char formation.
+Q: How should KR-26S be stored?
A: Sealed containers below 30°C, away from moisture and strong acids. 24-month shelf life. Flash point >110°C. Nitrile gloves and eye protection for handling.
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