So here is the beef against China: China uses hackers to steal American tech and pharma research, then makes the products and sells them for much less than the American companies would. And the American companies don't get any royalties.
TPP is supposedly going to fix this, by getting the TPP nations to refuse to buy, or allow the sale of, these Chinese products. This will, it is hoped, make the Chinese theft of technology from the US less profitable to the Chinese and discourage the practice.
The problem is, how do you get the TPP nations to agree not to buy the much cheaper Chinese versions of the technology America claims to own? Probably you do that by offering them very low prices... much lower than the prices Americans will pay for the same goods.
And that is probably one of the Big Secrets of TPP. If Americans knew that Japanese will pay much less for US pharma products than they do, they might pressure Congress for price controls. And that wouldn't do at all -- it would reduce profits for the American corporations.
A deeper problem, though, is simply one of basing a high-tech economy on technological secrets. Tech secrets are bound to leak, be hacked, be reverse-engineered, be independently discovered. America would love to be able to enforce its IP law globally, but it can't -- there is too strong an incentive for cheating, and US global economic power is waning.
To a large extent, TPP seems like a finger in the dyke of inevitable economic and technological change. The Internet Era inherently tends to make information freely available. Manufacturing technology is moving in the direction of "replicator"-like ability to make anything anywhere if you have the "recipe", but the US seems to want to freeze in place an economic system founded on secrets and manufacturing restrictions.