Identify a trade or industry association related to your product idea. Associations conduct research on behalf of their members and make some of them available free of charge. Scour websites for free publications, or call the association directly and speak to the librarian or public relations if you have specific questions.
Try searching Google with the suffix PDF at the end of your search term and you will get different results including conference proceedings and reports.
Douglas D. Schumann Library & Learning Commons
Wentworth Institute of Technology
550 Huntington Avenue
Boston, MA 02115