SIS

Product Overview

Modern adhesive and polymer formulations require materials capable of combining elasticity, tack development, cohesive properties, and thermoplastic processability. Styrenic Block Copolymers are widely used where manufacturers need rubber-like behavior together with the processing advantages of thermoplastic materials.

SIS (Styrene-Isoprene-Styrene) is a Styrenic Block Copolymer (SBC) supplied by SiNDA through qualified international manufacturing partners for adhesive, sealant, polymer modification, and specialty industrial applications.

SIS is composed of polystyrene blocks and elastomeric polyisoprene segments arranged in grade-dependent block-copolymer architectures. This molecular structure can provide a combination of elasticity, flexibility, tack response, and mechanical integrity, making SIS particularly relevant to pressure-sensitive adhesive and hot-melt formulations.

At normal service temperatures, the styrene domains act as physical crosslinking points that contribute to cohesive strength and dimensional stability. The polyisoprene phase provides the elastomeric behavior responsible for flexibility, elongation, and tack development.

Because SIS behaves as a thermoplastic elastomer, it can be softened and processed at elevated temperatures and then recover its elastomeric character after cooling. This makes it suitable for hot-melt processing and other industrial manufacturing methods.

Different SIS grades may vary in styrene content, diblock content, molecular weight, linear or radial architecture, melt viscosity, solution viscosity, hardness, and tack performance. Product selection should therefore be based on the intended formulation, processing method, and finished-product requirements.

SiNDA supplies SIS for industrial applications with available technical documentation, commercial shipment traceability where applicable, and international sourcing and supply support.

Key Benefits

• Styrene-Isoprene-Styrene block copolymer technology

• Supports tack development in adhesive formulations

• Good elasticity and flexibility
• Thermoplastic processability

• Grade- and formulation-dependent cohesive properties

• Suitable for hot-melt adhesive systems
• Elastomeric flexibility and recovery
• Available in multiple grades
• Available technical documentation
• International supply through SiNDA

Operational Applications

SIS is primarily intended for manufacturers developing adhesive and specialty polymer systems where tack, flexibility, and elastic recovery are important performance requirements.

Typical applications include:

• Pressure-sensitive adhesives
• Hot-melt adhesives
• Tapes and labels
• Hygiene adhesive systems
• Sealants
• Polymer modification
• Specialty compounds
• Elastic films and related polymer applications
• Specialty industrial formulations

The suitability of SIS should be evaluated according to formulation chemistry, tackifier selection, process oil content, polymer architecture, processing temperature, and finished-product performance requirements.

Technical Overview

SIS is a Styrene-Isoprene-Styrene block copolymer belonging to the Styrenic Block Copolymer (SBC) family.

SIS contains rigid polystyrene blocks and elastomeric polyisoprene segments arranged in architectures that can vary by grade. The styrenic domains contribute physical crosslinking and cohesive properties, while the polyisoprene phase provides elasticity, flexibility, and tack-related characteristics.

This combination enables SIS to function as a thermoplastic elastomer with processing characteristics suitable for hot-melt and solvent-based adhesive manufacturing.

Important grade variables include:

• Styrene content
• Diblock content
• Molecular weight
• Molecular-weight distribution
• Linear or radial architecture
• Melt viscosity
• Solution viscosity
• Hardness
• Tensile properties
• Elongation
• Tackifier compatibility

Actual performance depends on SIS grade selection, formulation design, and processing conditions.

Performance Characteristics

Tack & Adhesion Performance

SIS is widely used in adhesive formulations where tack development, surface wetting, and cohesive-adhesive balance are important performance considerations.

This can support:

• Pressure-sensitive adhesion
• Tack development
• Surface wetting
• Bond-performance contribution

Final adhesion performance depends strongly on tackifier chemistry, process oil, polymer concentration, and substrate type.

Elastomeric Flexibility

The elastomeric polyisoprene phase provides rubber-like elasticity and flexibility.

Potential benefits include:

• High elongation
• Elastic recovery
• Softness
• Flexible bond lines
• Resistance to cracking under deformation

Thermoplastic Processability

SIS softens at elevated temperatures and can be processed using conventional hot-melt and thermoplastic equipment.

This supports:

• Hot-melt blending
• Extrusion
• Coating
• Compounding
• Adhesive application processes

Cohesive Strength

The styrenic domains contribute to the internal cohesion and mechanical integrity of SIS-based formulations.

Depending on grade and formulation, this may support:

• Cohesive-property contribution
• Dimensional stability
• Adhesive-film integrity
• Grade-dependent mechanical performance

Compatibility & Limitations

SIS may be compatible with various tackifiers, process oils, resins, and other formulation components used in adhesive and polymer systems, depending on the specific grade and formulation.

Compatibility should be evaluated with:

• Hydrocarbon tackifier resins
• Rosin ester tackifiers
• Process oils
• Plasticizers
• Fillers
• Other styrenic block copolymers
• Selected polyolefins

Because the polyisoprene block contains unsaturation, SIS may be sensitive to oxidation, heat, ozone, and prolonged UV exposure unless appropriately stabilized.

For applications requiring improved weathering, oxidation resistance, or long-term thermal durability, a hydrogenated styrenic block copolymer such as SEPS may be more suitable.

Selection Guidance

SIS may be suitable for manufacturers seeking:

• Tack development in adhesive formulations
• Pressure-sensitive adhesive capability
• Thermoplastic processing
• Elastomeric flexibility
• Flexible formulation design
• Application-specific cohesive properties
• Hot-melt processing capability

Before selecting an SIS grade, manufacturers should evaluate:

• Target adhesive application
• Styrene content
• Diblock content
• Polymer architecture
• Molecular weight
• Tackifier compatibility
• Melt viscosity
• Processing temperature
• Required softness or hardness
• Final bond performance

Product suitability should be confirmed through formulation trials and production-scale testing.

Compliance & Technical Documentation

SiNDA supplies SIS with available technical and commercial documentation to support industrial evaluation, supplier qualification, and procurement.

Available documentation may include:

• Technical Data Sheet (TDS)
• Safety Data Sheet (SDS)
• Certificate of Analysis (COA)
• Batch-specific quality documentation
• Storage and Handling Recommendations
• Commercial shipment documentation
• Export Documentation

Published typical values should not be interpreted as guaranteed specifications unless confirmed by the manufacturer’s current TDS and batch-specific COA.

Why Choose SiNDA

SiNDA supplies styrenic block copolymers through qualified international manufacturing partners, supporting adhesive and polymer manufacturers with product access, available technical documentation, sourcing coordination, and commercial supply.

Key advantages include:

• Qualified international manufacturing sources
• Available technical documentation
• Coordinated commercial sourcing
• Batch traceability
• Support for supplier qualification
• Technical communication support
• International logistics capability

• RFQ and procurement assistance

Frequently Asked Questions

What is SIS?

SIS is a Styrene-Isoprene-Styrene block copolymer that combines elastomeric flexibility with thermoplastic processability.

What is SIS mainly used for?

SIS is widely used in pressure-sensitive adhesives, hot-melt adhesives, tapes, labels, hygiene adhesive systems, sealants, and specialty polymer compounds.

What is the main difference between SIS and SBS?

SIS contains elastomeric polyisoprene segments, while SBS contains polybutadiene segments. SIS is widely used in adhesive formulations where tack development and pressure-sensitive adhesion are important performance requirements.

Is SIS a thermoplastic elastomer?

Yes. SIS behaves like an elastomer under service conditions but can be processed like a thermoplastic at elevated temperatures.

Is SIS resistant to weathering?

SIS has limited resistance to prolonged heat, oxidation, ozone, and UV exposure due to unsaturation in the isoprene block. Stabilization may therefore be required.

What documentation is available?

Depending on the manufacturing source and grade, SiNDA may provide TDS, SDS, COA, batch documentation, storage guidance, and export documentation.