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D5 (Decamethylcyclopentasiloxane, CAS 541-02-6): Cosmetic Volatile Silicone and Specialty Polymer Feedstock
SEMITECH D5 is the fractionated decamethylcyclopentasiloxane — used as both a direct cosmetic ingredient (volatile carrier in antiperspirant, foundation, hair-care) and as a specialty feedstock for D5-derived silicone fluid. Higher boiling point (210°C) than D4 (175°C) gives slower-evaporation dry-feel. ≥99.5% purity, EU REACH SVHC documentation on every shipment.
Contents
| 541-02-6 | ≥99.5% | 210°C |
|---|---|---|
| CAS number | Purity | Boiling point |
Chemistry & Specifications
Ten-membered Si-O ring with 10 methyl groups; clear colourless liquid; bp 210°C; SVHC vPvB classification.
D5 (CAS 541-02-6) — MW 370.8, density 0.957 g/cm³, RI 1.396, bp 210°C, flash point 78°C (Class II combustible). SEMITECH supplies at ≥99.5% by GC, D4 ≤0.2%, D6+ ≤0.3%, water ≤30 ppm, acidity ≤2 ppm, APHA ≤10. 30–35% yield from DMC fractionation (vs 50–60% for D4), carrying a 5–15% cost premium over D4.
Applications: Cosmetic Carrier, Personal Care, Polymer Feedstock
Antiperspirant aerosol, hair-care leave-on, sun-care, foundation/BB cream, dry-feel personal care, polymer feedstock.
Cosmetic direct ingredient (largest) — antiperspirant aerosol (5–25%), hair-care leave-on (10–40%), foundation/BB cream (15–30%), sun-care (5–20%), shave gel (3–10%). D5 evaporates over 5–30 min leaving non-greasy dry-feel. D5-derived silicone fluid — medium-volatility 5–10 cP grades retaining 10–30% unpolymerised D5. Specialty silicone gum and optical-clarity silicone for LED encapsulation.
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EU REACH SVHC Designation and Personal-Care Compliance
D5 listed on REACH SVHC (vPvB); wash-off cosmetic limits scheduled; leave-on limits under review.
D5 is SVHC (vPvB, listed 2018). Wash-off cosmetics face 0.1% limit from 2030+; leave-on limits under ECHA review. Industrial silicone use remains permitted. Many global brands are progressively reformulating D4 first while maintaining D5 through 2030. SEMITECH provides full REACH compliance documentation on every shipment.
Procurement, Storage and Quality Control
CoA per shipment with cyclic GC breakdown; 200 kg drum / 1 t IBC; 24-month shelf life; flash point 78°C — Class II combustible.
CoA per batch: D5 purity (≥99.5%), D4 (≤0.2%), D6+ (≤0.3%), water (≤30 ppm), acidity (≤2 ppm), APHA (≤10). MOQ 200 kg. Lead time 2–4 weeks Asia, 4–6 weeks Europe/North America. Flash point 78°C — less stringent than D4. Shelf life 24 months sealed. Cosmetic-grade upgrade available: USP-NF microbial limits, ICH Q3D heavy metals, customer-specific compliance letters (NMPA, PMDA, MFDS) with 4-week lead time and 25–35% upcharge.
D5 Specification Sheet
SEMITECH stocked grade; CoA per batch with cyclic GC distribution.
| Property | Specification | Test Method |
|---|---|---|
| Chemical name | Decamethylcyclopentasiloxane | — |
| CAS number | 541-02-6 | — |
| Molecular formula | C₁₀H₃₀O₅Si₅ | — |
| Molecular weight | 370.8 g/mol | — |
| Purity (D5) | ≥99.5% | Gas chromatography |
| D4 impurity | ≤0.2% | GC |
| D6+ impurity | ≤0.3% | GC |
| Water content | ≤30 ppm | Karl Fischer |
| Acidity (as HCl) | ≤2 ppm | Potentiometric titration |
| APHA colour | ≤10 | ASTM D1209 |
| Density (25°C) | 0.957 g/cm³ | ASTM D1475 |
| Refractive index (25°C) | 1.396 | ASTM D1218 |
| Boiling point | 210°C (atmospheric) | — |
| Flash point | 78°C (closed cup) | ASTM D93 |
| Flammability classification | Class II combustible / EU CLP not classified flammable | — |
| EU REACH | SVHC candidate list (vPvB) — industrial use permitted | — |
| Packaging | 200 kg HDPE-lined steel drum / 1 t IBC / 25 t ISO-tank | — |
| Shelf life | 24 months sealed below 30°C | — |
FAQ
+D4 vs D5 in cosmetic formulation?
D4 (bp 175°C, faster evaporation) for foundation/BB cream — immediate dry-down in 2–5 min. D5 (bp 210°C, slower evaporation) for antiperspirant, hair-care leave-on — 5–30 min residence time. Many formulations blend both: typical antiperspirant 60% D5 + 40% D4; typical foundation 30% D5 + 70% D4.
+How does D5 EU REACH timeline differ from D4?
D4 leave-on limit 0.1% from 2027; D5 limits track 2–3 years behind. Industrial use of both remains permitted. Most global brands are reducing D4 first, maintaining D5 through 2030.
+Standard vs cosmetic-grade D5?
Standard: 99.5%+, heavy metals tested but not certified to cosmetic limits. Premium cosmetic-grade: 99.9%+, ICH Q3D certified, USP-NF microbial limits, full cGMP chain. Cost 30–50% more. SEMITECH offers cosmetic-grade upgrade with 4-week lead time.