STR was founded in 1944 by two of the world's most prominent polymer scientists. Over the years, STR has expanded and evolved into two core businesses – Solar Encapsulants Manufacturing and Quality Assurance Services.

STR's Solar Encapsulants Manufacturing business is one of the world's leading providers of high quality, superior performance solar encapsulants – marketed under the trade name Photocap® since 1979 – for the photovoltaic module industry. With over 100 international customers, including many of the top names in the solar module business, STR has developed many of the major innovations in the industry.

STR's Quality Assurance Services business is one of the top providers of quality testing, audit, inspection, and responsible sourcing services in the world. We work with over 2,000 major manufacturers, importers, raw materials suppliers, and retailers around the globe to ensure that they have the highest level of confidence in the quality, safety, and social standards of their products and systems.