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Kraton™ MD6951 M is a high-flow SEBS with 34% Polystyrene content. It features a 45 Shore A hardness, 16.5 MPa tensile strength, and 730% elongation at break. With a 20/80 styrene/rubber ratio, it is the ideal high-performance polymer for melt-blown nonwovens, precision injection molding, and food-grade packaging.
| Manufacturer | Kraton |
|---|---|
| Polystyrene Content | 34 % |
| Tensile Strength at Yield | 16.5 MPa |
| Elongation at Break | 730 % |
Note: See the product description for additional technical specifications
Kraton™ MD6951 M is a tri-block copolymer based on styrene and ethylene/butylene, belonging to the hydrogenated styrene-butadiene-styrene block copolymer (SEBS) family. This product is manufactured and supplied by Kraton Corporation (USA), a global leader in styrenic block copolymers (SBC).
Kraton MD6951 M is a polymer with a transparent, linear structure and a polystyrene content of 34%. It is supplied in macerated crumb form, with the surface treated with silica dust to prevent blocking. The most prominent feature of this product is the unique balance between high strength and high fluidity, allowing it to maintain excellent mechanical properties while adapting to processing techniques with extremely high flow requirements, such as melt-blowing, injection molding, and rotational molding.
Please note: MD6951 M is currently a Market Development Grade product of Kraton. Its specifications may be adjusted based on market feedback. It is recommended to perform sufficient testing before large-scale application.
The following data are based on ASTM test standards and Kraton internal methods (KM), providing a direct benchmark for engineers and technical personnel.
| Property | Typical Value | Test Method |
| Polystyrene Content | 34 % | Internal Method |
| Shore A Hardness (30 sec) | 45 | ASTM D2240 |
| Tensile Strength at Yield | 16.5 MPa | ASTM D412 |
| Elongation at Break | 730 % | ASTM D412 |
| Styrene/Rubber Ratio | 20/80 | — |
Based on its unique combination of high fluidity and high strength, Kraton MD6951 M is widely used in the following fields:
Specific Applications: Automotive interior skins, dashboard skins, armrest coverings, weatherstrips, and dampening pads.
Suitability: SEBS offers excellent aging and UV resistance and achieves a soft touch without added plasticizers. The high fluidity of MD6951 M allows for the molding of complex automotive parts via injection or slush molding.
Specific Applications: High-elastic breathable films, medical melt-blown nonwovens, and elastic components for hygiene products.
Suitability: MD6951 M is one of the few SEBS grades currently available for the melt-blown process. Its extremely low melt viscosity allows it to form ultrafine fibers through melt-blown dies, producing elastic and breathable nonwoven materials.
Specific Applications: Preparation of high-performance TPE alloys blended with polypropylene (PP), polyphenylene oxide (PPO), or polystyrene (PS); continuous fiber-reinforced thermoplastic composites.
Suitability: MD6951 M has excellent compatibility with polyolefins and styrenic resins like PP and PS. Used as a toughening modifier in engineering plastics, it significantly improves impact resistance and flexibility.
Specific Applications: Food packaging gaskets, soft-touch handle overmolds, wearable device straps, and toys.
Suitability: SEBS is a hydrogenated polymer with no double bonds, offering outstanding chemical stability and aging resistance. MD6951 M can be used directly for injection or extrusion without processing oil, avoiding oil migration and meeting food contact safety requirements.
Specific Applications: Used as a base material for producing various thermoplastic elastomer (TPE) compounds supplied to downstream injection molders.
Suitability: Its high fluidity reduces energy consumption during compounding and increases the acceptance of fillers or plasticizers, making it an ideal substrate for TPE modifiers.
| Parameter | Kraton MD6951 M | Ordinary SEBS (e.g., G1650) |
| Polymer Structure | Linear | Linear |
| Molecular Weight | Lower | Higher |
| Melt Flow Rate (MFR) | 36 – 50 (Ultra-high) | < 10 (Lower) |
| Tensile Strength | ~2400 psi (High) | ~3000 psi (Slightly Higher) |
| Elongation at Break | 730% | 600% |
| Processing Methods | Injection, Melt-blown, Rotational | Extrusion, Conventional Injection |
| Oil Extension Required | Can be processed oil-free | Usually requires oil for flow |
| Typical Applications | Melt-blown, thin-walled parts | Extruded tubes, cables, asphalt |
| Parameter | Kraton MD6951 M (SEBS) | SEPS (e.g., G1702) |
| Mid-block | Ethylene/Butylene (EB) | Ethylene/Propylene (EP) |
| Heat Resistance | Good | Superior |
| UV/Aging Resistance | Excellent | Excellent |
| Fluidity | Extremely High | Moderate |
| Polyolefin Compatibility | Excellent | Excellent |
| Cost | Market Dev Grade, Competitive | Typically Higher |
To ensure product quality and maximize production efficiency, here are professional processing parameters for Kraton MD6951 M:
SEBS itself is non-hygroscopic and usually does not require drying.
If exposed to high humidity for long periods or for high-requirement surfaces (e.g., transparent films), drying at 60-80°C for 2-4 hours is recommended.
| Item | Recommended Range |
| Barrel Temperature | 180 – 220°C |
| Nozzle Temperature | 190 – 210°C |
| Mold Temperature | 20 – 40°C |
| Injection Pressure | 30 – 70 MPa |
| Back Pressure | Low to Medium |
| Item | Recommended Range |
| Melt Temperature | 220 – 250°C |
| Die Temperature | 230 – 260°C |
| Screw Speed | Adjust per equipment to avoid high shear |
Compatibility: MD6951 M has excellent compatibility with PP, PE, PS, and PPO, and can be used to prepare TPV or TPE alloys.
Oil Extension: Unlike conventional SEBS, MD6951 M can be processed without oil. If lower hardness or cost is needed, white oil or naphthenic oil can be added (recommended oil content not exceeding 30%).
Temperature Control: Processing range is wide (180-260°C), but avoid staying above 300°C for long periods to prevent thermal-oxidative degradation.
Equipment Cleaning: Purge the screw with PP or PE before and after processing to avoid cross-contamination.
Market Development Status: Specifications may change. Verify with the latest TDS and perform small-batch trials before large-scale purchase.
Q1: What is the biggest difference between Kraton MD6951 M and ordinary SEBS?
The biggest difference is the ultra-high fluidity. The MFR of MD6951 M (36-50 g/10min) is 5-10 times that of ordinary SEBS. This allows it to handle processes impossible for ordinary SEBS, such as melt-blown nonwovens and rotational molding, and to be used without processing oil.
Q2: Does MD6951 M require plasticizers or processing oil?
No. This is a major advantage. Conventional SEBS requires 20-50% oil to improve processing. MD6951 M, due to its unique molecular design, has extremely low melt viscosity and can be used directly, simplifying formulas and avoiding oil migration issues.
Q3: Can MD6951 M be blended with other plastics?
Yes, compatibility is excellent with PP, PE, PS, and PPO. It is often used as a toughening modifier, a TPE base material, or a compatibilizer. Twin-screw extrusion at 190-230°C is recommended for blending.
Q4: Does MD6951 M meet food contact or medical requirements?
It is currently a Market Development Grade product, and formal certification (FDA, ISO 10993) may not yet be published. While it has high purity and potential for food contact, users should contact Kraton for the latest regulatory compliance statements and perform independent testing (e.g., GB 4806, FDA 21 CFR 177.1810).
