Some inventions may employ a proprietary branded product. The only way to describe and claim such products is to refer to them by the trademark. This presents unique problems for the patent prosecutor because a branded product is usually not in the control of the patent applicant, and can therefore change after the application is drafted and filed. This is a particular problem in the claims, where the changing scope could invalidate the claim or make the claim impossible to infringe.

The MPEP addresses the use of trademarks in a patent application:

VELCRO appears in the claims of 2077 patents; TEFLON appears in the claims of 3585 patents; ETHERNET appears in the claims of 7425 patents; and JAVA appears in 3690 patents. For examples, see U.S. Patent No. 6,959,462, Claim 2 (VELCRO); U.S. Patent No. 8,485,489, Claim 12, and 8,062,571, claim 4 (TEFLON); U.S. Patent No. 8,457,003, Claims 2, 3, U.S. Patent No. 8,422,359, claim 10, and U.S. Patent No. 8,363,655, claim 5 (ETHERNET); and U.S. Patent No. 8,330,862, Claim 4, and U.S. Patent No. 8,254,757 (JAVA).