Suzhou Pharmaceutical Technology Co., Ltd. (China) supplies SIS Rubber CAS 26914-43-2 for pharmaceutical B2B procurement — COA, MSDS, and technical documentation available on request.
> Overview: SIS Rubber — CAS 26914-43-2
Suzhou Pharmaceutical Technology supplies SIS rubber, CAS 26914-43-2, pharmaceutical grade, from qualified Chinese manufacturers. Styrene-isoprene-styrene (SIS) block copolymer is the dominant elastomeric material for drug-in-adhesive (DIA) transdermal drug delivery systems (TDDS), pressure-sensitive medical tapes, and wound-care bandages. Available in linear (triblock) and radial (star) architectures, with styrene content 14–30% w/w and solution viscosity 500–5,000 mPa·s. Each lot ships with COA, MSDS, styrene content (FTIR/NMR), and viscosity data. Minimum 25 kg; bulk supply to Argentina, Colombia, Chile, Peru, Ecuador, and across South America by sea freight.
> Technical Profile & Specifications
SIS rubber is an ABA triblock copolymer: two rigid polystyrene end-blocks (A) flanking a flexible polyisoprene mid-block (B). Below the glass transition temperature of polystyrene (~100 °C), the polystyrene domains form physical cross-links, giving SIS rubber its elastomeric network and cohesive strength. Above 100 °C, the cross-links soften, enabling hot-melt processing. The polyisoprene mid-block provides oxygen permeability, skin conformability, and compatibility with lipophilic APIs and mineral oil plasticizers.
| Property | Value |
|---|---|
| Product Name | SIS Rubber |
| Structural Formula |  |
| CAS Number | 26914-43-2 |
| Purity | Polymer grade; volatile impurities ≤200 ppm (GC headspace) |
| Polymer Type | ABA triblock copolymer (styrene–isoprene–styrene) |
| Styrene Content | 14–30% by weight (grade-dependent) |
| Diblock Content | ≤20% (triblock-rich pharma grades) |
| Number-Average Mw | 100,000–250,000 g/mol (GPC) |
| Solution Viscosity | 500–5,000 mPa·s (25% w/v toluene, 25 °C) |
| Mooney Viscosity | ML(1+4) at 100 °C: 5–40 MU (grade-dependent) |
| Ash Content | ≤0.1% |
| Volatile Impurities | ≤200 ppm total (GC headspace) |
| Appearance | White to off-white bales or pellets |
| Hot-Melt Processing | 110–180 °C (standard range) |
| Storage | ≤25 °C, RH ≤60%, away from UV light; sealed |
> Regulatory Status
- FDA Inactive Ingredients Database: Styrene-isoprene-styrene block copolymer listed as excipient in transdermal dosage forms.
- USP/NF: SIS rubber used in transdermal systems; no separate monograph — covered under Styrene-Isoprene-Styrene Block Copolymer in Transdermal Drug Delivery guidelines.
- REACH (EU): CAS 26914-43-2; classified as UVCB substance; produced under REACH Annex VI provisions.
- ISO 10993: Pharma-grade SIS rubber tested for biocompatibility (cytotoxicity, sensitization) for skin-contact medical device applications.
- South America: Accepted as excipient in transdermal patch formulations registered with ANMAT (Argentina), INVIMA (Colombia), ISP (Chile), and DIGEMID (Peru).
> Pharmaceutical Applications
- Drug-in-adhesive transdermal patches: Primary elastomeric matrix at 15–35% w/w in mineral oil (20–40%) and hydrocarbon tackifier resin (10–25%) blends. APIs dissolved or suspended at 5–25% w/w. Commercial examples: nicotine patches, fentanyl patches, clonidine patches, hormone therapy patches (estradiol, testosterone).
- Pressure-sensitive medical tapes: SIS + rosin-ester tackifiers for medical-grade tapes, ostomy flanges, and wound-care dressings requiring gentle adhesion and clean removal.
- Wound care bandages: Conformable elastic bandages and cohesive wraps; polyisoprene mid-block provides stretch and recovery matching skin mechanics.
- Hot-melt coating: Solvent-free adhesive layer application by slot-die hot-melt coating at 130–160 °C; preferred over solvent casting for environmental and cost reasons.
Wokovich AM et al. (Eur J Pharm Biopharm. 2006;64(1):1–8, doi:10.1016/j.ejpb.2006.03.009, n=15 patch formulations) established that adhesion properties — peel force, tack, and cohesive strength — are critical quality attributes for TDDS safety and efficacy, directly linking SIS rubber matrix composition to regulatory acceptance of transdermal pharmaceutical products.
> Industrial Applications
- Hot-melt pressure-sensitive adhesives (HMPSAs): Packaging tapes, labels, and non-woven assembly adhesives using SIS + tackifier + plasticizer formulations.
- Bitumen modification: SIS and SBS block copolymers are the dominant modifiers for polymer-modified bitumen (PMB) in road asphalt, improving high-temperature performance and low-temperature crack resistance.
- Sealants & roofing: SIS-based sealants for construction and roofing membranes requiring elastomeric recovery.
> Quality Assurance & Documentation
- Styrene content: FTIR (1600 cm⁻¹ phenyl ring absorption) or ¹H NMR; accuracy ±1%
- Solution viscosity: Brookfield LV/DV, 25% w/v in toluene, 25 °C; ±5%
- Mooney viscosity: ASTM D1646, ML(1+4) at 100 °C
- Ash content: ISO 247; ≤0.1%
- Volatile impurities: GC headspace; ≤200 ppm total residual solvent
- Color: Gardner scale; ≤3 (water-white to pale yellow)
Documentation with each shipment: COA, MSDS/SDS (GHS format), and country-of-origin certificate. For ≤25 kg qualification orders, digital PDFs within 24 h of shipment; for >25 kg commercial orders, physical originals plus digital copies.
> Sourcing & Manufacturing Origin
China is one of the world’s largest SIS rubber producers. Suzhou Pharmaceutical Technology sources from manufacturers with dedicated pharmaceutical-grade SIS production lines, controlled anionic polymerization processes, and ISO 9001 certification. Our suppliers operate stringent quality control for styrene content consistency (±1%), low volatile content, and heavy-metal compliance, meeting the requirements of pharmaceutical-grade customers in Japan, South Korea, Europe, and the Americas.
> Packaging, Storage & Shipping
- ≤25 kg: 25-kg paper-wrapped bales or PE-lined carton boxes
- 25–500 kg: Multiple bales on wooden pallets, stretch-wrapped
- >500 kg: Full pallet lots (500–1000 kg) or bulk container on request
Storage: Keep below 25 °C, away from UV light and ozone (both degrade polyisoprene double bonds). Sealed packaging preserves quality for 2 years. Avoid contact with strong oxidizers.
Shipping: Non-hazardous (UN not regulated). Sea freight FCL/LCL from Shanghai or Tianjin to Buenos Aires, Callao (Lima), Valparaíso, Cartagena, and Guayaquil. HS code: 4002.19.00. Air freight for qualification samples ≤5 kg. Typical transit: 28–35 days to Buenos Aires.
> Pricing & MOQ
- Pharma-grade linear SIS (14–22% styrene): 25–200 kg from USD 5–9/kg; 200–1000 kg from USD 3.5–6/kg
- Pharma-grade radial SIS (22–30% styrene): +10–20% premium vs. linear grades
- Technical/industrial grade: 15–25% lower than pharma grade
MOQ: 25 kg for qualification; 200 kg for commercial orders. Price validity 30 days from quotation. All prices FOB Shanghai; CIF or DDP to South American ports on request.
> Frequently Asked Questions
What is the minimum order quantity and what sample sizes are available for pharmaceutical SIS rubber?
Two main variants: Linear SIS (triblock, 14–22% styrene) for high-cohesion patches, and Radial SIS (star-shaped, 22–30% styrene) for firmer matrices. Pharma-grade lots: low volatile impurities (≤200 ppm), heavy metals ≤10 ppm. COA includes styrene content, viscosity, Mooney viscosity, color, and volatiles profile.
What documents are included with pharmaceutical SIS rubber shipments?
COA with styrene content (FTIR/NMR), solution viscosity (Brookfield), Mooney viscosity ML(1+4) at 100 °C, color (Gardner), ash content, and volatile impurities; MSDS/SDS (GHS); country-of-origin certificate. Factory attestation letters and DMF-support documents on request. Documents in English; Spanish translations for ANMAT, INVIMA, and ISP.
What is the CAS number 26914-43-2 for SIS rubber?
CAS 26914-43-2 identifies styrene-isoprene-styrene (SIS) block copolymer in trade and regulatory databases. SIS is a UVCB substance under REACH — no single molecular formula applies. Known under trade names Kraton D, Vector SIS, and Taipol SIS. Listed in FDA Inactive Ingredients Database for transdermal dosage forms.
How is SIS rubber used in transdermal drug delivery systems?
SIS forms the elastomeric matrix of drug-in-adhesive (DIA) patches at 15–35% w/w in mineral oil/resin blends. Provides controlled API diffusion, skin adhesion (peel force 3–15 N/cm), cohesive strength, and 2-year stability. Wokovich AM et al. (Eur J Pharm Biopharm. 2006;64(1):1–8, doi:10.1016/j.ejpb.2006.03.009, n=15 patch formulations) showed adhesion is a critical quality attribute for TDDS performance.
What is the styrene content of pharma-grade SIS rubber?
Styrene content by grade: Low (14–18%): soft, tacky matrices for sensitive-skin patches. Mid (18–25%): standard for most TDDS formulations. High (25–30%): firmer matrices for longer-wear patches and medical tapes. Measured by FTIR (1600 cm⁻¹ phenyl ring) or ¹H NMR; accuracy ±1%.
How does SIS rubber differ from SBS rubber for transdermal applications?
SIS uses a polyisoprene mid-block; SBS uses polybutadiene. For transdermal use: SIS has higher O₂ permeability (~90 vs ~45 Barrers), broader tackifier resin compatibility, and higher elasticity for skin conformability. SBS is harder and preferred for industrial hot-melt adhesives. SIS is the standard elastomer for pharmaceutical transdermal patches.
What molecular weight ranges are available for pharmaceutical SIS rubber?
Mn typically 100,000–250,000 g/mol by GPC. Low Mw (100–130k): lower-viscosity hotmelt processing. Mid Mw (130–180k): standard DIA patches. High Mw (180–250k): high-cohesion applications. Solution viscosity (25% w/v toluene, 25 °C): 500–5,000 mPa·s depending on grade.
Is pharma-grade SIS rubber compatible with common transdermal APIs?
SIS is compatible with lipophilic APIs (log P >1.5): fentanyl, nicotine, estradiol, testosterone, clonidine, diclofenac at 5–25% w/w in SIS/mineral oil/resin matrices. Hydrophilic APIs (log P <1) have poor solubility in SIS; in those cases, hydrogel or reservoir patch designs are preferred. Penetration enhancers (oleic acid, propylene glycol) are generally compatible.
What packaging is available for bulk SIS rubber shipments to South America?
Standard: 25-kg paper-wrapped bales or PE-lined carton boxes; 500-kg pallets for bulk orders. Sea freight FCL/LCL to Buenos Aires, Callao (Lima), Valparaíso, Cartagena, and Guayaquil. Lead time 4–6 weeks. DDP and CIF Incoterms available.
What is the minimum order quantity for pharmaceutical SIS rubber?
MOQ 25 kg for qualification; 200 kg for commercial orders. Pharma-grade linear SIS: USD 5–9/kg at 25–200 kg (FOB Shanghai). Price validity 30 days. Contact our team for CIF pricing to your South American port.
How does SIS rubber compare to acrylate adhesives for transdermal patches?
SIS hot-melt matrices: higher tack with mineral oil/resin, excellent skin conformability, no residual solvent, lower drug loading (~10–20%). Acrylates (solvent-cast): lower tack without tackifiers, higher drug loading (up to 30–40%), better for hydrophilic APIs. SIS preferred for OTC transdermal products (nicotine, pain-relief bandages) where cost and processability are key.
Do you supply pharmaceutical SIS rubber to Argentina and Colombia?
Yes — primary markets. We ship to Buenos Aires (Exolgan) and Bogotá/Medellín (via Cartagena). Documentation compatible with ANMAT and INVIMA: COA, MSDS, factory attestation letter. DDP and CIF available. Transit 28–35 days from Shanghai or Tianjin.
> Related Transdermal & Adhesive Materials
- White Petrolatum (CAS 8009-03-8) — occlusive emollient, ointment base, wound-care matrix
- Titanium Dioxide (CAS 13463-67-7) — opacifier and UV filter in patch backing layers
- Succinic Acid (CAS 110-15-6) — pH modifier and buffer in transdermal formulations
> Request a Quote — SIS Rubber CAS 26914-43-2
Suzhou Pharmaceutical Technology supplies pharmaceutical-grade SIS rubber (CAS 26914-43-2) in quantities from 25 kg to multi-tonne lots, with full regulatory documentation. We serve importers, formulators, and manufacturers in Argentina, Colombia, Chile, Peru, Ecuador, Bolivia, Uruguay, and worldwide. Last reviewed: 2026-06-03