pretty big actually. There is a lot of chemicals that needs to be produced and most of those chemicals are not actually used for carbon fibers. I have the data on things like acrylic fiber where China has far and away the most capacity. But they get used for other purposes too.
It's kind of interesting that the only real competition vs Chinese production right now is Toray. I mean there are some smaller Japanese and Korean companies. But Toray pretty much has like a monopoly in Western countries.
btw, this is the entire carbon fiber production process
Just look at how chemical intensive the upstream is. And the carbon fiber precursors are produced from Polyacrylonitrile (or acrylic fiber) made by the chemical plants.
China has by far world's largest supply of Acrylic production with 吉林化纤 also being the largest producer of this.
So it's not only the largest producer of carbon fiber in China, but also the feedstock that goes into it.
Of course, it helps that Jilin is not far from Daqing oil field and gets cheap electricity. That allowed the chemical industry to get developed in the first place.