## Facts

- DuPont owned multiple federal registrations for the trademark TEFLON (registered beginning in 1946) and related certification marks; the registrations remained in force and DuPont gave statutory notice.
- TEFLON identified DuPont’s fluorocarbon resin used in nonstick coatings and related applications.
- Yoshida International, Inc. and Yoshida Kogyo K.K. (collectively, YKK) manufactured and sold zippers and entered the U.S. market with a nylon zipper branded EFLON.
- YKK sought to register EFLON; DuPont opposed the registration and filed suit seeking injunctive relief for trademark infringement.
- YKK asserted TEFLON had become generic for the nonstick feature and therefore was no longer protectable.
- YKK offered consumer surveys showing that many consumers, when asked to name the nonstick feature, used “Teflon,” while relatively few identified DuPont as the maker.
- DuPont offered a survey asking respondents to classify terms as brand names or common names; most respondents classified TEFLON as a brand name.

## Issues

1. Whether TEFLON’s primary significance to the relevant public had become generic, making the mark invalid or unenforceable.
2. Whether YKK’s use of EFLON on zippers created a likelihood of confusion with TEFLON, including confusion as to sponsorship or affiliation.
3. Whether DuPont was entitled to injunctive relief.

## Decision

- The court upheld TEFLON as a valid, protectable trademark and rejected YKK’s claim that TEFLON had become generic.
- The court found YKK’s use of EFLON was sufficiently similar to TEFLON and likely to cause confusion, including mistaken assumptions of association or approval.
- The court granted injunctive relief against YKK’s infringing use of EFLON.

## Legal Principles

- A mark is generic, and therefore unprotectable, if its primary significance to the relevant public is the product or feature rather than the producer or source.
- Survey evidence is probative on genericness, but the survey design must measure the legal question (consumer understanding of brand name versus common name), not merely whether consumers use a term in everyday speech.
- Infringement turns on likelihood of confusion, which may include confusion as to sponsorship, affiliation, or approval, not only confusion as to identical source.
- Similarity of marks, the strength of the senior mark, the relationship of the goods in the marketplace, and evidence suggesting an attempt to benefit from the senior mark’s goodwill support a finding of likely confusion and equitable relief.

## Conclusion

The court concluded that TEFLON retained trademark significance despite widespread public usage and that YKK’s EFLON mark, closely resembling TEFLON, was likely to cause confusion; it therefore enjoined YKK’s use of EFLON.


E.I. DuPont de Nemours & Co. v. Yoshida Int’l, Inc., 393 F. Supp. 502 (E.D.N.Y. 1975)