PVC
PVC (PolyVinylChlorine) is generally classified into 7 levels based on the hardness and properties of the material (SG1-SG7), with a density of 1.4 g/cm ³ Left and right. SG4 and below are generally soft products that require a large amount of Plasticizer during molding. They are mainly used to make artificial leather, insulation layers for wires and cables, seals, etc. SG5 and above are hard products mainly used to make various pipes, such as drainage, electrical, postal and telecommunications pipes and fittings, various plates, sheets, profiles, etc. The shrinkage rate of PVC molding is 0.6-1.5%, which has good mechanical properties, excellent electrical properties, strong self extinguishing ability, ACID and alkali resistance, good chemical stability, and low price. It is a widely used general-purpose plastic. However, its development is hindered by its low usage temperature, reaching a maximum of around 80 ℃.
CPVC
Resin is a new type of engineering plastic made by chlorination modification of polyvinyl chloride (PVC) resin. This product is a white or light yellow, odorless, and non-toxic loose particle or powder. After chlorination, the irregularity and polarity of molecular bonds in Pvc Resin increase, leading to increased solubility and chemical stability of the resin, thereby improving the material's heat resistance, acid resistance, alkali resistance, salt resistance, oxidant corrosion, etc. The mechanical properties of the numerical hot deformation temperature have been improved, with the chlorine content increasing from 56.7% to 63-69%, the Vicat softening temperature increasing from 72-82 ℃ to 90-125 ℃, and the maximum operating temperature reaching 110 ℃. The long-term operating temperature is 95 ℃. Among them, CORZAN CPVC has better performance indicators. Therefore, CPVC is a new type of engineering plastic with broad application prospects.
UPVC
UPVC pipes use Polyvinyl Chloride Resin as a carrier, which has excellent characteristics such as accurate temperature sensing, timed melting, and rapid absorption of effective ingredients of additives when reducing the attraction between resin molecular chains. At the same time, they use world-renowned calcium zinc composite heat stabilizers, which can capture, suppress, absorb and neutralize the release of hydrogen chloride during the resin's high-temperature and melting process. They undergo double bond addition reactions with the polyene structure, replacing the active and unstable chlorine atoms in the molecules. So as to effectively and scientifically control the catalytic degradation and oxidative decomposition of resin in a molten state.
PP
PP pipe is a semi crystalline material. It is harder and has a higher melting point than PE. Due to the brittleness of homopolymer type PP at temperatures above 0 ℃, many commercial PP materials are irregular copolymers with 1-4% ethylene added or clamp copolymers with higher ethylene content. Copolymer type PP materials have lower thermal distortion temperature (100 ℃), low transparency, low glossiness, and low rigidity, but they have stronger impact strength. The strength of PP increases with the increase of ethylene content. The Vicat softening temperature of PP is 150 ℃. Due to its high crystallinity, this material has excellent surface stiffness and scratch resistance. PP does not have environmental stress cracking issues. Usually, PP is modified by adding glass fiber, metal additives, or thermoplastic rubber. The flow rate of PP has an MFR range of 1-40. PP materials with low MFR have better impact resistance but lower tensile strength. For materials with the same MFR, the strength of copolymer type is higher than that of homopolymer type. Due to crystallization, the shrinkage rate of PP is quite high, generally ranging from 1.8 to 2.5%. And the directional uniformity of shrinkage rate is much better than materials such as PE-HD. Adding 30% glass additive can reduce the shrinkage rate to 0.7%. Both homopolymer and copolymer type PP materials have excellent resistance to moisture absorption, acid and alkali corrosion, and dissolution. However, it has no resistance to solvents such as aromatic hydrocarbons (such as benzene) and chlorinated hydrocarbons (carbon tetrachloride). PP does not have the same antioxidant properties as PE at high temperatures.
Polypropylene (PP) is a lighter type of common plastic with excellent electrical properties, and can be used as a high frequency insulation material that is resistant to moisture and heat. PP is a crystalline polymer that exhibits a significant shrinkage rate (1.0% -1.5%) during melt condensation due to significant changes in specific volume and high degree of molecular orientation. PP has little effect on reducing its viscosity by increasing temperature in the molten state. Therefore, in the molding process, the main focus should be on increasing the injection pressure and shear rate to improve the quality of the product.
PE
The full name is Polythene, which is the simplest polymer organic compound and the most widely used polymer material in the world today. It is polymerized from ethylene and can be divided into high-density polyethylene, medium density polyethylene, and low-density polyethylene according to different densities. Low density polyethylene is relatively soft and is often polymerized under high pressure; High density polyethylene has the characteristics of rigidity, hardness, and high mechanical strength, and is commonly used for low-pressure polymerization. High density polyethylene can be used as containers, pipelines, and high-frequency electrical insulation materials for radar and television. Low density (high-pressure) polyethylene is commonly used in large quantities. Polyethylene is wax like and has a waxy smoothness. When not dyed, low-density polyethylene is transparent, while high-density polyethylene is opaque. Polyethylene is a high polymer chain formed by the addition and polymerization reactions of ethylene (CH2=CH2), connected by repeated - CH2- units. The performance of polyethylene depends on its polymerization method; High density polyethylene (HDPE) is produced by Ziegler Natta polymerization under the catalytic conditions of organic compounds under moderate pressure (15-30 atmospheres). The polyethylene molecules polymerized under these conditions are linear, with long molecular chains and a molecular weight of several hundred thousand. If free radical polymerization is carried out under high pressure (100-300 MPa), high temperature (190-210 C), and peroxide catalyzed conditions, low-density polyethylene (LDPE) is produced, which has a branched structure.
Polyethylene is insoluble in water and has little water absorption. It only slightly dissolves in some chemical solvents, such as toluene and Acetic Acid, at temperatures above 70 ℃. However, particulate polyethylene can melt or solidify with temperature changes between 15 ℃ and 40 ℃, and melt and absorb heat as the temperature increases; When the temperature decreases, it solidifies and releases heat. Because it has a small water absorption capacity, is not easily damp, and has insulation performance, it is a good building material.
PB
Polybutene was developed and applied in the early 1970s, and its material characteristics determined that high technical and equipment requirements were required for the production of profiles. Fixed asset investment was also significant, and general small-scale manufacturers did not have the technical conditions and financial capabilities for production.
PVDF polyvinylidene fluoride
The appearance is semi transparent or white powder or particles, with tightly arranged molecular chains and strong hydrogen bonds. The oxygen index is 46%, non flammable, with a crystallinity of 65%~78%, a density of 1.17~1.79g/cm3, a melting point of 172 ℃, a hot deformation temperature of 112~145 ℃, and a long-term use temperature of -40~150 ℃.
PVDF resin mainly refers to homopolymers of vinylidene fluoride or copolymers of vinylidene fluoride and other small amounts of fluorinated vinyl monomers. PVDF resin combines the characteristics of fluorine resin and general-purpose resin. In addition to good chemical corrosion resistance, high temperature resistance, oxidation resistance, weather resistance, and radiation resistance, it also has special properties such as piezoelectricity, dielectric properties, thermoelectric properties, etc. It is currently the second largest production product in fluorinated plastics, with a global annual production capacity of over 43000 tons. The application of PVDF is mainly concentrated in the three major fields of petrochemical, electronic and electrical, and fluorocarbon coatings. Due to its good chemical resistance, processability, fatigue resistance, and creep resistance, PVDF is one of the best materials for pumps, valves, pipelines, pipeline fittings, storage tanks, and heat exchangers in the fluid treatment system of petrochemical equipment as a whole or lining. Its good chemical stability and electrical insulation performance enable the equipment manufactured to meet the requirements of TOCS and flame retardancy. It is widely used in the storage and transportation of high-purity chemicals in the semiconductor industry. In recent years, porous membranes, gel, diaphragms, etc. made of PVDF resin have been used in lithium secondary cells. At present, this use has become one of the fastest growing markets for PVDF demand. PVDF is one of the main raw materials for fluorocarbon coatings, and fluorocarbon coatings prepared from it have developed to the sixth generation. Due to the strong weather resistance of PVDF resin, it can be used outdoors for a long time without maintenance. This type of coating is widely used in power plants, airports, highways, high-rise buildings, etc. In addition, PVDF resin can also be modified by blending with other resins, such as PVDF and ABS resin to obtain composite materials, which have been widely used in construction, automotive decoration, home appliance shells, and so on.
PVC material is a type of plastic decorative material. PVC is the abbreviation of polyvinyl chloride material, which is made of polyvinyl chloride resin as the main raw material, adding appropriate anti-aging agent, modifier, etc., through mixing, calendering, vacuum plastic absorption and other processes.
PVC materials have the characteristics of lightweight, thermal insulation, moisture resistance, flame retardancy, and easy construction. Specifications, colors, patterns
It is diverse and highly decorative, and can be applied to the decoration of indoor walls and ceilings. It is one of the most widely used decorative materials in plastic materials.
The advantages of PVC buckle plates mainly include the following aspects:
1. Lightweight, insulated, moisture-proof, flame retardant, acid and alkali resistant, and corrosion-resistant.
2. Good stability, dielectric property, durability, anti-aging, easy fusion and bonding.
3. Strong bending strength and impact toughness, with high elongation when ruptured.
4. It is easy to process and shape through processes such as kneading, mixing, pulling, pelletizing, extrusion, or die casting, which can meet the needs of various profile specifications.
5. Smooth surface, bright color, highly decorative, with a wide range of decorative applications.
6. The construction process is simple and the installation is relatively convenient.
The PE pipe is made of polyethylene material, which is suitable for concealed installation. The exposed material is prone to aging.
PP-R pipes not only have the advantages of light weight, good strength, corrosion resistance, no scaling, and long service life of general plastics, but also have the following main characteristics:
(1) Non toxic, hygienic, and belongs to the category of green building materials. PP-R raw materials belong to polyolefins, whose molecules are composed of carbon and hydrogen elements, non-toxic, and have excellent hygiene properties;
(2) Heat resistant, insulated, and energy-saving products. The softening temperature of PP-R pipes is 131.3 ℃, with a maximum usage temperature of 95 ℃. The long-term (50 years) usage temperature can reach up to 70 ℃. The thermal conductivity of this product is 0.24W/m ℃, which is only 1/200 of the thermal conductivity of steel pipes. It has excellent insulation and energy-saving effects when used for hot water pipelines;
(3) Easy and reliable installation, using hot melt homogeneous connection, a joint connection can be completed in a few seconds. High quality metal fittings are used to connect with metal pipes and water heaters, ensuring safety and reliability.
Application fields of PP-R cold and hot water pipes
Cold and hot water systems inside buildings, including centralized heating systems;
The heating system inside the building, including floor and wall panel heating and radiation heating systems;
Direct drinking purified water supply system;
Central (centralized) air conditioning system;
Agriculture and garden irrigation systems;
Rainwater pipe network;
Swimming pool pipeline network;
The pipeline network of solar facilities;
PPR is generally used for small pipe diameters, and can be installed openly or covertly.
PB pipe is a polymer material of polybutene, which has been widely used in developed countries such as Europe and America, and has replaced copper pipe as the preferred material for hot water supply pipelines.
The main raw materials for PEX pipes are HDPE, as well as initiators, crosslinking agents, catalysts and other additives. If there are special requirements, other modifiers can also be added.
The PEX tube is manufactured using the world's advanced one-step method (MONSOL method) technology, using ordinary polyethylene raw materials added with silane grafting materials to form chemical covalent bonds between polymer macromolecular chains to replace the original van der Waals forces, thereby forming a three-dimensional cross-linked network structure of polyethylene, with a crosslinking degree of 60% to 89%, making it have excellent physical and chemical properties.
ABS is a ternary copolymer based on styrene butadiene acrylonitrile, which has high impact toughness, good mechanical strength, heat resistance, oil resistance, etc
PVC pipes are used for laying electrical wires in households, and they should be standard fire-resistant PVC pipes. There are also some re laid sewage pipes that use PVC pipes. The commonly used PPR is used in the renovation of waterways, and PPR is more suitable for water.
The essential difference is the difference in raw materials. PPR is random copolymer polypropylene, while PVC is polyvinyl chloride. PVC can be used for water supply and drainage, while PPR is mainly used for water supply (the cost of using it for drainage is too high). In fact, PVC is not necessarily toxic. Many medical infusion tubes and plastic packaging are made of PVC, and what is used for construction is only the addition of modifiers. Moreover, PPR can be used for hot melt PVC.
PPR is produced from copolymerized polypropylene material, while PVC is produced from polyvinyl chloride material. The former has high production cost, better hygiene level than PVC, and can handle hot water below 75 ℃, but the disadvantage is that it is relatively easy to deform. PVC is widely used for irrigation in farmland due to its low production cost, but its disadvantage is that it can only use cold water.
PE pipe
Temperature resistance
The low-temperature embrittlement temperature of PE water supply pipes is very low and can be used within the range of -40 ℃ to 60 ℃. Winter installation and construction will not cause pipeline embrittlement.
Corrosion resistance
Polyethylene is an inert material that can withstand erosion from various chemical media and does not require anti-corrosion protection. Chemical substances in the soil will not cause any degradation of the pipeline, and will not cause decay, rust, or corrosion.
Flexibility
The elongation at break of PE water supply pipes exceeds 800%, and local vibration will not cause all pipes to vibrate. It has strong seismic resistance. The flexibility of polyethylene allows PE water supply pipes to be coiled, reducing a large number of connecting fittings and bypassing obstacles during construction, reducing construction difficulty.
Voltage resistance
Due to the high crystallinity of HDPE, its strength and hardness increase accordingly. The fusion joint is tight and can withstand internal pressure, making it widely used in water supply and pressure pipelines.
Hygienic
Hygienic and non-toxic, the pipes do not breed bacteria, and will not cause secondary water pollution, completely solving the problem of pipeline pollution of water sources.
Circulation capacity
The inner wall of PE water supply pipe is smooth, with low friction coefficient, low fluid resistance, low head loss, no scaling, reducing pressure loss and water transmission energy consumption of the pipeline, and obvious economic advantages.
Pipeline safety
The PE water supply pipe adopts hot melt connection and electric melt connection, and the interface strength is higher than the strength of the pipe body, which can effectively resist the circumferential and axial forces generated by internal pressure. The sealing performance is good, and there is no need to worry about interface distortion causing pipeline leakage.
