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Polymer Modification

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Kraton polymers are blended with plastics such as styrenics, polyolefins and engineering thermoplastics to improve performance, particularly impact, by toughening these plastics at low or room temperatures. Depending on the application needs, either transparent or non-transparent solutions can be offered. These polymers help compatibilize different plastics to bring out the best in each material, enhance the impact strength of scrap or regrind materials, and improve processability to allow for higher filler or reinforcement loadings. 



Kraton polystyrene end blocks provide good compatibility with crystal polystyrene and high impact polystyrene (HIPS), making it good impact modifiers, especially for low temperature applications like food packaging.

For non-transparent applications, USBC polymers may be used (Kraton™ D1101, Kraton™ D1102, Kraton™ D1155 or Kraton™ D1157)Kraton D1101 is the most effective grade given its impact strength, while Kraton D1102 is easy to process and is often used when only mild shear rate compounding equipment (e.g. single screw) is available. Kraton D1155 and CirKular+ C3000 are the preferred products for upgrading recycled polystyrene and high impact polystyrene from the waste stream.


Unmodified polypropylene homopolymer (hPP) has high rigidity and good heat resistance but has poor impact resistance, especially at low temperatures. Combining Kraton polymers with hPP can improve toughness at both room and low temperatures.

Many applications for impact modified PP require a balance of high flow, high stiffness (modulus) and excellent impact performance, but PP only offers high melt flow (> 30g/10 min.). Often talc, silica or other natural fillers are used to increase stiffness (modulus).  Kraton polymers help to increase significantly impact for effective use in thin-walled part designs such as automotive instrument panels and exterior bumper systems.

For non-transparent applications, low molecular weight grades supplied in dense pellet form, offer optimal results since it forms a homogenously dispersed blend composition. Various Kraton HSBC products provide best-in-class balance of flow, modulus and impact strength in combination with talc-filled PP copolymer blends. Kraton HSBC polymers can deliver good weatherability and heat aging performance.

To improve transparency, Kraton enhanced rubber segment (ERS) are used to modify random copolymer PP. The products are delivered as dense pellets, allowing for easy handling and mixing.  Kraton ERS polymers can be sterilized by steam, EO, EB or gamma radiation; it meets most stringent food and medical regulations.

CirKular+™ Performance Enhancement Series are versatile multi-resin compatibilizers to enhance performance of recycled PP and polyolefinic blends across a wide range of applications.

Kraton polymers can be used in tubing, film, sheet and injection molded products. To achieve the optimal formulation and performance results, please contact Kraton Sales Representative for the specific grade recommendations.  


Kraton offers a series of functionalized hydrogenated styrenic block copolymers (HSBC) to improve compatibility with polar engineering thermoplastics (ETP), such as polyamides (PA) and high temperature polyamides (HTPA). These functionalized block copolymers, produced by the maleation of an SEBS product, are effective modifiers for toughening a variety of polyamide chemistry. The saturated rubber midblock allows it to withstand ETP processing conditions with heat aging performance and good weatherability.
CirKular+ Compatibilization Series  is a high-performance multi-resin compatibilizer for recycled polyamide and nylon streams even if contaminated with other resins.


Polyphenylene Ether
Kraton polymers are compatible and effective impact modifiers for polyphenylene ether (PPE). Similar to polystyrene, the higher molecular weight styrenic block copolymers (SBC) are more efficient in toughening PPE, providing a unique micro-structure. If heat aging performance, weatherability and  limited degradation during processing is critical, Kraton™ G1651, Kraton™ G1654, Kraton™ G1650, Kraton™ G1701, and Kraton™ A1536  or a blend hereof, are recommended.


Polycarbonate is very tough material. Thinner parts (3.2 mm) can achieve a notched Izod at room temperature in the 950 J/m range, but thicker parts (6.4 mm) can become brittle with notched Izod of only 125 J/m range. To toughen thick polycarbonate parts, Kraton™ G 1651 polymer can be added to the material at 5 percent to increase the notched Izod (6.4 mm) by a factor of six at room temperature.


Thermoplastic Polyester Elastomer
Thermoplastic polyester elastomer (TPE-E), also known as COPE or TPC-ET, has excellent low temperature impact strength, very good chemical resistance and heat aging performance, but its major drawbacks is hardness limitation. Kraton™ A polymers were developed to overcome such limitation. These polymers are compatible with TPE-E and offer improved isotropic properties, which enable very thin part injection molding. Compared to traditional Kraton HSBC, Kraton A polymers exhibit more polarity, allowing for excellent dispersion of fillers and color concentrates in such compositions. Ultra-high flow Kraton™ MD6951 is the most efficient grade to achieve lower hardness of TPE-E formulation.



Plastics today have found its way into more demanding applications. For that, it is designed and engineered to meet specific needs, and most of it uses a combination of polymer types to meet these requirements. Kraton styrenic block copolymers (SBC) – can be used for modification of various resin combinations, acting as a compatibilizer and impact modifier for virgin, bioplastics and recycled resins. CirKular+ productline has been designed for use for a wider range of recycled streams.

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