Floor heating pipe is one of the core components of the floor heating system, so the choice of pipe material is also the most important. It is directly related to the operation of the entire system and directly affects the realization of the heating effect.

Plastic pipes not only have the advantage of corrosion resistance, but also have low prices. With the continuous increase in the cost of copper and steel, the market for plastic pipes for water delivery is booming. The use of plastic pipes for hot water transportation is mainly used in areas such as geothermal facilities, heating facilities and drinking water pipes. Due to its obvious advantages, the share of plastic pipes used in modern geothermal systems has accounted for more than 90% of the entire market. Among them, PEX tubes are widely used, accounting for about 70%. In contrast, steel pipes and copper pipes, as the main materials for heating facilities and sanitary pipes, account for the gradual decline in the overall market share.

In the PEX cross-linked polyethylene series, PE-Xa and PE-Xc are used as the mainstream choice. The following introduces high-density polyethylene (PE) as one of the core materials of floor heating. Adding a cross-linking agent to chemically cross-link or Three kinds of pipes, PE-Xa, PE-Xb and PE-Xc produced by physical crosslinking.

Now, the realization conditions of the floor heating pipes produced by these three cross-linking methods and the advantages and disadvantages of the products are analyzed.

1. PE-Xa pipe: referred to as peroxide cross-linking method. The peroxide crosslinking agent is added to the polyethylene, and the crosslinking process of the plane network is gradually completed under the action of a certain temperature (230 degrees Celsius). This cross-linking method requires high cross-linking conditions, and the degree of cross-linking will not change once it is formed. It is a process of cross-linking first and then forming. Its product features are good surface finish, good flexibility, but poor acid resistance and oxidation resistance. The product formed by this method is called PE-Xa.

2. PE-Xb pipe: referred to as silane crosslinking method. The silane cross-linking method is to add a silane agent and a catalyst to the polyethylene, and complete the three-dimensional network cross-linking process in the hydrolysis process after forming. This kind of cross-linking method requires relatively low conditions, as long as there is water and a certain temperature. Completed, the storage and packaging requirements of its raw materials are relatively high. The silane crosslinking method is a process of forming first and then crosslinking. The product is characterized by high surface strength and tensile strength, but poor water resistance, and the degree of product crosslinking will move with time. The product formed by this method is called PE-Xb.

3. PE-Xc pipe: referred to as radiation cross-linking method. The radiation crosslinking method is a physical crosslinking method. Compared with the first two (oxide, silane), the crosslinking process does not require other additives. It is to make the main chain of polyethylene macromolecule form new free radicals after being irradiated by pure high-density polyethylene pipe products, and the free radicals recombine to form crosslinks, and the molecular structure changes from linear arrangement to Three-dimensional three-dimensional network structure, the thermoplastic plastic is changed to thermosetting plastic. This kind of cross-linking method requires extremely high conditions, thereby greatly enhancing the performance of the pipe, and the cross-linking is very stable.