Product Overview & China Production Capacity
Styrene-Isoprene-Styrene (SIS) Rubber is a thermoplastic elastomer block copolymer used as the primary elastomeric base in transdermal drug delivery systems (TDDS), pressure-sensitive adhesives, and medical tapes. China’s SIS production capacity has grown rapidly, with major manufacturers in Hunan, Shandong, and Guangdong provinces operating anionic polymerization reactors capable of producing multiple SIS grades with controlled molecular weight and styrene/isoprene ratios. Annual Chinese SIS output exceeds 100,000 metric tons across all grades.
In pharmaceutical applications, SIS serves as the adhesive matrix in transdermal patches, providing skin adhesion, drug compatibility, and controlled release characteristics. Medical-grade SIS exhibits excellent tack, peel adhesion, and shear resistance while maintaining biocompatibility with skin contact. Chinese SIS producers offer linear and radial architectures with varying styrene content (14–22%) to enable formulators to optimize adhesion-cohesion balance for specific TDDS applications.
Manufacturing Standards & Quality Assurance
Production facilities hold ISO 9001:2015, ISO 14001:2015, and ISO 13485 (medical device grade) certifications. Quality testing includes styrene content (FTIR/NMR), molecular weight distribution (GPC), melt flow index, volatile matter, ash content, solution viscosity, and biocompatibility testing per ISO 10993 for medical-grade products. Products are manufactured under controlled atmospheric conditions using high-purity styrene and isoprene monomers with alkyllithium initiators.
Anionic living polymerization technology enables precise control of block lengths, molecular weight, and architecture. Post-polymerization processing includes antioxidant stabilization, solvent stripping, and pelletizing or baling. Medical-grade SIS undergoes additional extractables and leachables testing and USP Class VI biological reactivity evaluation.
Technical Specifications
| Parameter | Specification |
|---|---|
| Chemical Type | Styrene-Isoprene-Styrene Block Copolymer |
| Structure | Linear or Radial |
| Styrene Content | 14–22% (grade dependent) |
| Molecular Weight (Mw) | 100,000–300,000 (grade dependent) |
| Appearance | White to light yellow pellets or bales |
| Melt Flow Index | Grade dependent |
| Volatile Matter | ≤0.5% |
| Ash Content | ≤0.3% |
| Solution Viscosity (25% in toluene) | Grade dependent |
| Biocompatibility | ISO 10993 / USP Class VI (medical grade) |
Packaging & Export Logistics
SIS is supplied in 25 kg PE bags within kraft outer bags, or in bales wrapped in PE film on pallets. Bulk packaging in 500 kg or 1,000 kg units is available. Anti-oxidant packaging and nitrogen-purged options preserve product freshness during extended storage. Lead time is 15–20 business days. FOB shipment from Shanghai, Qingdao, or Guangzhou ports.
Documentation includes CoA, SDS, biocompatibility test reports (medical grade), and commercial shipping paperwork. Non-hazardous classification facilitates global shipping.
China Supply Advantage
Chinese SIS production combines advanced anionic polymerization technology with competitive operating costs to deliver pricing 20–35% below established Western producers. Growing capacity investments and R&D programs targeting medical and TDDS applications position Chinese SIS manufacturers as strategic alternative suppliers for global pharmaceutical patch manufacturers seeking supply chain diversification and cost optimization.