SPC Flooring Stabilizers
SPC (Stone Plastic Composite) flooring combines a rigid PVC/CaCO₃ core with a decorative film, wear layer, UV coating and optional IXPE underlay. While pigments, fillers and processes vary, PVC heat stabilizers are essential to control fusion, protect color and mechanical strength, and keep lines running clean. This article explains how Calcium‑Zinc (Ca‑Zn) and Methyl‑Tin (MT) stabilizers work in SPC, what to watch on the line, and how to meet today’s market hotspots: low VOC (FloorScore), low odor, dimensional stability, and fast installation.
Where Stabilizers Live in the SPC Stack
- Core (PVC + 60–75% CaCO₃): Requires robust heat stability for twin‑screw compounding and calendering; balanced internal/external lubrication to hit fusion and density targets; minimal plate‑out to keep rollers/embossing clean.
- PVC wear/transition layers (if any): Transparent or semi‑clear PVC sub‑layers beneath the PU/UV topcoat need stability without yellowing; consistent torque prevents gel/burn specks.
- Decor film / coatings: When PVC-based, stabilizer choice can influence color hold and odor; coatings demand clean substrates with low residuals.
Choosing Between Ca‑Zn and Methyl‑Tin
Calcium‑Zinc (Ca‑Zn) is now the mainstream for SPC due to lead‑free compliance (RoHS/REACH) and low odor/VOC. Modern Ca‑Zn packages combine Ca/Zn soaps with β‑diketones, organic phosphites, and hydrotalcite to deliver long‑term stability, flat torque curves, and good color hold at high filler ratios.
Methyl‑Tin (MT) offers very strong heat stability and excellent clarity—useful for clear rigid PVC. In SPC it’s typically considered for clarity‑critical transparent PVC layers where regulations allow. For the core and opaque layers, Ca‑Zn is preferred in many markets for environmental and odor reasons.
Practical approach: Use Ca‑Zn as the default for cores and opaque layers; evaluate MT only for clear layers or special compliance scenarios.
Process Control: Fusion, Torque & Plate‑Out
- Fusion & torque curve: Stabilizer and lube balance should achieve a quick rise to fusion, then a stable/flat torque plateau. This supports steady throughput and dimensional control.
- Plate‑out & die/roll cleanliness: Excessive plate‑out causes roller streaks and embossing defects. Choose low‑plate‑out Ca‑Zn packages; tune external lubricant levels and CaCO₃ treatment.
- Color/whiteness: Stabilizer synergy with TiO₂/optical brighteners matters; avoid over‑shear and local hot spots to limit yellowing or burn specks.
- Click‑lock machining: Good thermal stability mitigates edge brittleness during profiling; consistent fusion helps locking strength and reduces chip‑out.
Key Specifications to Watch
- Dimensional stability: ≤0.05–0.10% after thermal cycling/aging (target ranges vary by spec).
- Locking strength: Meet profile system targets (Unilin/Valinge‑compatible); avoid brittle edges.
- VOC/odor: Aim for FloorScore/TVOC compliance; favor low‑odor Ca‑Zn systems and optimized lubricants/ESBO co‑stabilizers.
- Fire class: Bfl‑s1 options available depending on full construction.
- Wear layer: 0.3 / 0.5 / 0.7 mm depending on traffic class; surface UV/PU for scratch/chemical resistance.
Hot Topics in 2025: What Buyers Ask
1) Low VOC & Odor: Buyers expect clean indoor air—FloorScore/EN testing is now common. Stabilizer choice, co‑stabilizers (e.g., ESBO), and process conditions all influence VOC.
2) Underfloor Heating Compatibility: Thermal cycling demands stable fusion and low residual stress; stabilizer/lube balance supports shrink/warp control.
3) EIR Textures & Matte Finishes: Keep rollers clean—low plate‑out stabilizers prevent print‑transfer and gloss banding on deep emboss.
4) Fast Lead Times: Stabilizer systems that deliver shorter start‑up and fewer die cleans directly improve uptime.
5) Sustainability & Compliance: Lead‑free is a must; REACH/RoHS and transparent VOC data are strong trust signals.
Formulation Tips (Ca‑Zn Systems)
- Pair Ca‑Zn with β‑diketone / organic phosphite / hydrotalcite for long‑term color/thermal hold.
- Balance internal vs. external lubricants for fusion time and surface quality; consider CaCO₃ coating level.
- Use ESBO judiciously as a co‑stabilizer/plasticizing aid—watch VOC/odor and migration specs.
- For click‑lock milling, favor systems that maintain impact and notch toughness at edges.
- Validate on your line: torque rheology, plate‑out check (roller wipes), ΔE color, stability at dwell, and locking strength.
Typical SPC Offering (Reference)
- Core thickness: 3.5 / 4.0 / 4.5 / 5.0 / 6.0 / 7.0 / 8.0 mm
- Wear layer: 0.3 / 0.5 / 0.7 mm
- Texture/finish: EIR / matte / semi‑matte / high‑gloss; micro or painted bevel
- Click system: Unilin/Valinge‑compatible; tight seam
- Underlay: IXPE 1.0 / 1.5 / 2.0 mm (pre‑attached optional)
FAQs (EN)
Q1. Should I always choose Ca‑Zn for SPC cores?
A1. In most markets yes—Ca‑Zn provides lead‑free compliance and low odor/VOC. Consider MT only for clarity‑critical transparent PVC layers where regulations allow.
Q2. How do stabilizers affect plate‑out?
A2. Poor stabilizer/lube balance can increase exudation and roller build‑up. Choose low‑plate‑out Ca‑Zn packages and optimize external lubricants and CaCO₃ treatment.
Q3. Can you support FloorScore/CE?
A3. Yes—we offer documentation and can tune formulations to help meet FloorScore/TVOC and Bfl‑s1 requirements depending on the full construction.
Q4. What inputs do you need to match our grade?
A4. Resin grade, CaCO₃ ratio & treatment, target fusion time/torque, line type (twin‑screw + calender parameters), wear layer and locking system targets.
Call to Action
Share your core recipe (PVC/CaCO₃ ratio), fusion/torque targets, and VOC/fire specs. We’ll return a matched Ca‑Zn package and lab data, with samples in 48 hours.
