Huntsman Takes Benzoxazine Resins to the Next Level

Huntsman’s expertise in thermoset resins innovation is today producing major improvements in the composites industry; the first in many years.  Our next-generation benzoxazine resins are helping design engineers fabricate high-performance composite parts that are stronger and better able to perform in high temperature, moist and corrosive environments than parts built using conventional epoxy, phenolic and bismaleimide systems.  New benzoxazine resins process faster and at lower temperatures than ever before and exhibit virtually no shrinkage after curing.  In addition, one of Huntsman’s newest systems features excellent flame, smoke and toxicity properties.

According to Ash Chaudhari, Vice President - Research and Technology, Huntsman Advanced Materials, “Benzoxazine chemistry opens the door for composite fabrication techniques never before possible with a single chemistry.  Now, manufacturers can realize the superior physical and mechanical characteristics of benzoxazine systems using processing methods including resin transfer molding (RTM), vacuum-assisted resin transfer molding (VARTM), filament winding and prepreg.”

Historical Background
Discovered in the 1940’s, benzoxazines have long been known for their excellent electrical, thermal and mechanical properties.  However, the early versions were difficult to handle due to the fact that they were solid materials which required a very high-temperature cure and produced brittle parts. 

As the market for composite parts expanded, so did the need for polymers that offered more cost-effective processing with higher part throughput.  Huntsman responded by working on reacting benzoxazine resins with epoxy- and phenol-based systems. 
The resulting new products were easier to handle, cured at lower temperatures and produced more robust parts.  The benzoxazines were also halogen-free, complying with increasingly strict environmental and regulatory demands. 

The benzoxazines Huntsman manufactured in the early 2000’s were known for their good electrical properties, making them ideal for laminating printed circuit boards.  During the last decade, Huntsman chemists worked in partnership with customers to create resins that met the industry’s needs for more economical fabrication of super-tough composites parts. 

New Benzoxazines Combine Performance, Processability

Huntsman’s next-generation resins combine excellent stiffness and high temperature performance with outstanding hot/wet strength.  They also have an unprecedented ability to withstand exposure to moisture, chemicals and other corrosive materials. 

The advantages of the new benzoxazines go well beyond outstanding physical capabilities.  They’re now safer and easier to handle and process than ever before.  Huntsman has formulated diluents and accelerators that produce benzoxazine formulations that maintain a liquid viscosity for longer than three hours at 212˚F (100˚C).  The resins cure at temperatures in the 350˚F (177˚C) range with some systems that cure out of autoclave.  Moreover, Huntsman’s benzoxazine products release approximately 20% less energy (when compared to traditional epoxy resins) and unlike phenolic resins do not generate volatiles during cure.  The products exhibit excellent long-term storage stability at room temperature.

Benzoxazine-based Composites…the Way of the Future

While current commercial benzoxazines offer numerous advantages over epoxies, phenolics and BMIs, Huntsman continues its research on the next generation of resins with a goal of creating additional new products for use in a broader range of applications. 

Dong Wang, Senior Scientist Technologist at Huntsman Advanced Materials, explains, “We are working to extend our knowledge about altering benzoxazine system reactivity and the ability to co-cure these base resins with other materials.  For example, by varying the combinations and amounts of base resin and hardeners in our formulations, we may be able to produce high-performance benzoxazine systems that cure at temperatures as low as 280˚F (130˚C) or that can withstand temperatures as high as 482˚F (250˚C).”
 
Huntsman is also actively partnering with manufacturers in emerging composites markets such as automotive, transportation, tooling and industrial parts to educate them about working with the new benzoxazine chemistries.  With greater familiarity about handling and processing, customers will optimize production efficiency as well as increase composite part quality.

According to Derek Kincaid, Senior Technical Manager, Huntsman Advanced Materials, “With the current capabilities of our unique family of benzoxazine products and our ongoing research and development efforts, we anticipate positive growth into many new markets and industries.”  He concludes, “Huntsman welcomes the opportunity to develop innovative benzoxazine resin systems that support and even spur that expansion.”

For more information about Huntsman Advanced Materials Benzoxazine solutions, please visit www.huntsman.com/BOX