Pultrusion is one of the most promising segments of the composites industry. The pultrusion end market in terms of value is expected to reach $2 billion by 2020, growing at a compound annual growth rate of 4.8 percent, according to a report by market research firm Markets and Markets.

From April 8 – 10, pultruders will gather at the North American Pultrusion Conference in Rosemont, Ill., to learn about new technologies, processes and products. Among the speakers will be experienced industry professionals discussing opportunities in three market segments: wind energy, infrastructure and utilities. Composites Manufacturing magazine’s managing editor talked to those experts for a sneak peek at their presentations and insight into application opportunities for pultruded products.

Market Segment: Wind Energy

For more than a decade, wind energy has been the biggest market for Zoltek Corporation’s industrial carbon fiber, says David Purcell, executive vice president of sales and marketing for Zoltek, a wholly-owned subsidiary of the Toray Group. “Most carbon fibers are associated with aerospace and high-end sporting goods, which tend to have less price sensitivity,” he says. “Zoltek approaches the market from the opposite end, on a cost-plus basis. It is not our primary goal to get qualified into aerospace programs. Instead, we try to compete with glass fiber, aluminum, steel and other base building materials.”

When Zoltek began selling carbon fiber for the wind energy market in the early 2000s, most wind blades were made from a combination of fiberglass prepregs and fabric. “Carbon fiber fabrics can present handling challenges and have the potential to wrinkle, and they have to go through the infusion process. Prepregs can have the same issues, and they are sensitive to the manufacturing environment. The degree of tack changes with how humid or cool the facility is,” says Purcell. “Since most wind blade manufacturing facilities are not closely climate controlled, they were looking for something more robust.”

Pultruded CFRP provided the solution, says Purcell. Approximately six years ago, pultruded CFRP spar caps and wind blades entered the market. Zoltek’s pultruded profiles are pre-cured, thick-ply carbon fiber laminates suited for structural reinforcement applications. “The pultrusion process locks in much better fiber alignment in the final composite, which alleviates many of the processing issues related to fabrics and prepregs,” says Purcell.

Zoltek’s pultruded profiles are available in a variety of standard formats, including flat plates and round rods. The profiles incorporate ZOLTEK PX35 continuous tow carbon fiber, made from a textile-based precursor and manufactured in a proprietary process. The 50K fibers have a tensile strength of 4,137 MPa (megapascals) and a tensile modulus of 242 GPa (gigapascals).