The main reason for the yellowing of PVC plastic pipe materials is that the amount of stabilizer is not enough or the grade is not good, and there will be redness. It is possible to use a stabilizer of very poor quality, but in most cases it is a problem caused by unbalanced lubrication, too little lubrication, especially too little external slippage, and overplasticizing causes the pipe to become discolored and brittle. You can add some TIO2 to see if it can cover it. If not, you can try adding stabilizer or replace it. If it is a calcium-zinc stabilizer, you should pay more attention to the adjustment of the lubricant. In addition, lubricants affect plasticization, calcium carbonate is added with whitening agents, etc., and PVC resins. Under the same conditions, poor PVC will become more yellow, requiring more stabilizers. Usually, the problem of stabilizers is thought of. In fact, when the stability is sufficient, lubrication is also a very important factor. In addition, if the calcium powder is wet, it will also affect the plasticization. Stabilizers are usually the first consideration, but problem solving can generally begin with proper adjustment of the lubricating system. If the problem of stabilizer is ruled out, the focus is on adjusting slip agent and dynamic balance. The stabilizers mentioned in the industry generally do not contain antioxidants, but calcium and zinc stabilizers usually contain antioxidants.
