Wynnchurch Capital has made a growth equity investment in Foss Manufacturing, a fabric manufacturer. The Hampton, NH-headquartered company is a vertically-integrated producer of engineering, non-woven fabrics and specialty synthetic fibers. Its solutions are used in several industries and applications, including automotive, commercial, residential, municipal/civil, craft/hobby, marine and medical. The extra capital will help finance Foss' growth plans. Middle-market investor Wynnchurch focuses on niche manufacturing, business and services, energy and power services, logistics, transportation and value-added distribution businesses.