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SZ-TPZ (Tetra-n-Propyl Zirconate, Kenrich NZ-01 Equivalent): Entry-Workhorse Organozirconate for CaCO₃-Filled PE Wire & Cable
SEMITECH SZ-TPZ is the entry-grade tetra-n-propoxide zirconate — Kenrich NZ-01 equivalent — for CaCO₃-filled PE wire & cable, structural foam, and high-loading masterbatches. 0.5–1.5 phr, 200°C thermal stability, 25 kg HDPE, 40–55% landed-cost discount vs Kenrich.
Contents
| NZ-01 | 0.5–1.5 phr | 200°C |
|---|---|---|
| Kenrich equivalent | Typical loading | Thermal stability |
Chemistry & Specifications
Zr(IV) tetra-n-propoxide; clear pale-yellow liquid; bare alkoxide — moisture-sensitive; lowest-cost zirconate.
SZ-TPZ (Zr(OC₃H₇)₄, MW 327.6) is supplied as ~70% solution in n-propanol. SEMITECH grade: ZrO₂ 18.5–19.5%, active ≥70%, water ≤0.2%. Pricing: CNY 38,000–45,000/MT vs Kenrich NZ-01 at USD 16–20/kg — 40–55% discount. Bare alkoxide nature requires N₂-blanketed storage.
Coupling Mechanism: Zr-O-Filler Surface Bond + n-Propoxide Hydrolysis
Zr alkoxide reacts with surface –OH on filler, releasing n-propanol; deposits Zr-O-filler covalent linkage.
- Loading 0.5–1.0 phr — standard CaCO₃-PE wire & cable insulation; high-loading filler dispersion
- Loading 1.0–1.5 phr — high-loading (60–70%) CaCO₃ masterbatches; mineral structural foam
- Loading 0.3–0.6 phr — fine-particle GCC and PCC fillers in food-contact PE film
Pre-coating filler at 80°C in a high-speed mixer is preferred for >50% loading. In-situ addition is acceptable for <30% loading. Typical uplift: tensile +15–25%, elongation +30–50%, MFI +20–40% vs uncoupled compounds.
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Applications & Formulation Guidance
CaCO₃-filled PE wire & cable (largest), high-loading mineral masterbatch, structural foam, GCC/PCC compounds.
CaCO₃-PE wire & cable insulation is the largest application — low-voltage building wire, telecom cable, irrigation tubing. SZ-TPZ at 0.5–1.0 phr enables CaCO₃ loading from 30% to 50–60% without sacrificing mechanical properties, providing 30–40% raw-material cost reduction.
High-loading masterbatches at 1.0–1.5 phr for 60–70% CaCO₃ carrier. Structural foam at 0.5–1.0 phr for automotive/appliance parts. GCC/PCC PE film at 0.3–0.6 phr for breathable nappies and packaging. Avoid SZ-TPZ for ATH/MDH above 200°C — use SZ-12 or SZ-44 instead.
Procurement, Storage and Quality Control
CoA per shipment; 25 kg HDPE; sealed nitrogen blanket; 12-month shelf life; 1-week stocked lead time to Asia.
Standard packing 25 kg HDPE under N₂; 200 kg drums for bulk wire & cable customers. MOQ 25 kg. Lead time 1 week to Asia, 4–6 weeks to Europe/North America. Store under N₂ below 25°C; consume within 30 days of opening. Flash point 23°C (n-propanol solvent).
SZ-TPZ Specification Sheet (70% Solution in n-Propanol)
SEMITECH stocked grade; CoA per batch.
| Property | Specification | Test Method |
|---|---|---|
| Chemical name | Tetra-n-propyl zirconate / Zirconium tetra-n-propoxide | — |
| Synonyms | TPZ / NZ-01-equivalent / Zr(OnPr)₄ | — |
| Molecular formula (anhyd.) | Zr(OC₃H₇)₄ | — |
| Molecular weight (anhyd.) | 327.6 g/mol | — |
| Form | 70 wt% in n-propanol | — |
| ZrO₂ content (in solution) | 18.5–19.5% | Gravimetric / XRF |
| Active content | ≥70% | Titration |
| Appearance | Clear pale-yellow to amber liquid | Visual |
| Density (20°C) | 0.99–1.01 g/cm³ | ASTM D1475 |
| Viscosity (25°C) | 20–40 cP | Brookfield |
| Water content | ≤0.2% | Karl Fischer |
| APHA colour | ≤200 | ASTM D1209 |
| Flash point | 23°C (solvent, closed cup) | ASTM D93 |
| Thermal stability | 200°C continuous | — |
| Solubility | n-propanol, n-butanol, toluene; reacts with water | — |
| Packaging | 25 kg HDPE under N₂ / 200 kg lined steel drum | — |
| Shelf life | 12 months sealed below 25°C under N₂ | — |
FAQ
+How does SZ-TPZ compare to a silane coupling agent (KH-560 / KH-570) on calcium carbonate?
SZ-TPZ wins on hydrolytic stability (Zr-O-Ca more durable than Si-O-Ca) and thermal stability (200°C vs ~180°C). Silanes win on cost (~USD 4–5/kg vs SZ-TPZ ~USD 6/kg) and industry familiarity. Wire & cable favours SZ-TPZ; general filler-extension favours silane.
+Can I substitute SZ-TPZ for SZ-12 in an ATH-filled HFFR cable compound?
Not recommended. SZ-TPZ degrades above 200°C and lacks the phosphate anchor for ATH surfaces, resulting in 5–10 LOI drop and 20–30% tensile loss vs SZ-12. The SZ-12 cost premium is justified.
+Pre-coating filler vs in-situ compounding addition — which is better?
Pre-coating is preferred for >50% filler, fine-particle GCC/PCC, and production-scale wire & cable. In-situ is acceptable for <30% filler and lab-scale — expect 10–20% lower coupling efficiency, compensate with 25–50% higher loading.