PVC pipes will change color for various reasons during use. Consumers will blame the quality of PVC pipes when they see discoloration of PVC pipes. In fact, the reason for the discoloration of the PVC pipe is not only the quality of the PVC pipe. Let’s take a look at the reasons for the discoloration of PVC pipes.
Quality of PVC products
Because of the presence of tertiary chlorine and allyl chloride in the molecular structure of PVC, the PVC pipe is prone to decompose during the production process and later in use, causing the pipe to begin to change color. The order of color changes is white, pink, yellow, red, and black ( carbonization), so PVC quality, stabilizer quality (to control decomposition), and dosage are critical.
Discoloration induced by the unqualified titanium dioxide
There are usually two structural forms: anatase and rutile. Due to their different structures, performance, and aging resistance. It must be a rutile type when used as PVC pipe. However, due to the production quality problems of some manufacturers or due to uneven surface coating, discoloration (greying) is prone to occur under the condition of photocatalysis.
Sulfur pollution and lead salt stabilizer, cadmium stabilizer
With the development of industry, the problem of acid rain and sulfide pollution is becoming more and more serious, and in the process of storage and transportation, profiles may come into contact with sulfide, so the possibility of sulfide pollution is very high. The substance produced by the sulfur pollution reaction is black or red, which can cause the white substance to change color, so the lead salt stabilizer profile is prone to sulfur pollution. Cadmium stabilizer is a toxic product. If used in pipes, it will cause the yellowing of pipes in a sulfide environment, so cadmium stabilizers are rarely used.
The above are the reasons for the discoloration of PVC pipes. IFAN will share them with you, hoping to help you.
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