Opinion ID: 398222
Heading Depth: 4
Heading Rank: 2

Heading: TKPP and TSP substituted for borax in lubricants

Text: 20 The Special Master also ruled that General Motors' use of tetrapotassium pyrophosphate (TKPP) as a borax substitute in bumper making (accused practices 6, 14, 50, 52, and 53) and of trisodium phosphate (TSP) as a borax substitute in non-bumper making (accused practices 3, 11, 15 and 45) infringed the Devex patent. Special Master's Report at 29-38; Appendix at 289-298. 21 The Special Master found as a fact that TKPP was put in (to the lubricant) as a borax substitute, to help the soap do the job of efficiently lubricating the workpiece. Special Master's Report at 31; Appendix at 291. General Motors argued that the use of TKPP did not infringe the patent because pure TKPP melts at a higher temperature than the ferrous metal phosphate coating, which meant that TKPP did not fit the literal language of the patent. The Special Master rejected that argument, found as a fact that TKPP, when mixed in the coatings and as a matter of actual practice, melts before the ferrous metal phosphate coating, and concluded that the use of TKPP as a borax substitute to improve lubricity and cleanability therefore infringed the Devex patent. Special Master's Report at 32-37; Appendix at 292-297. The Special Master also found that TSP (accused practices 3, 11, 15, 45) has a lower melting point than the ferrous metal phosphate coating, and that if it were used as a borax substitute to obtain improved lubricity and cleanability it would infringe the Devex patent. Special Master's Report at 37-38; Appendix at 297-98. 22