PVC is a polymer of vinyl chloride monomer in an initiator such as peroxide or an azo compound; or a polymer obtained by a free radical polymerization mechanism under the action of light or heat. It is a thermoplastic material that repeatedly melts at certain temperatures and hardens on cooling. Its main component is polyvinyl chloride, a material that adds other ingredients to enhance its heat resistance, toughness and ductility. PVC is divided into rigid and flexible and can be combined with a variety of additives to make soft and hard PVC pipes. PVC-U pipe has strong corrosion resistance, easy bonding, low price and hard texture. It is used in drainage, wastewater, chemicals, heating liquid and coolant, food, ultra-pure liquid, mud, gas, compressed air and vacuum system. Then why do you have to make PVC hose and PVC flexible joints?