Differences in performance of PVC, UPVC, CPVC, PP, PE, PB, PVDF plastic pipesDifferences in performance of PVC, UPVC, CPVC, PP, PE, PB, PVDF plastic pipes
PVC (PolyVinylChloride polyvinyl chloride) generally has 7 grades (SG1-SG7) according to the hardness and performance of the material, and the density is about 1.4 g / cm³. Below SG4 is generally a soft product, and a large amount of plasticizer needs to be added during molding. It is mainly used to make artificial leather, wire and cable insulation, and seals. SG5 and above are hard products, mainly used to make various pipes, such as drainage, electricians, post and telecommunication pipes and pipe fittings, various plates, sheets, profiles, etc. PVC molding shrinkage is 0.6-1.5%, has good mechanical properties, excellent electrical properties, and has self-extinguishing, strong acid and alkali resistance, good chemical stability, low price, is a very widely used General-purpose plastic. But because its use temperature is not high, the highest is about 80 ℃, which hinders its development.
The resin is made of chlorinated modification of polyvinyl chloride (PVC) resin and is a new type of engineering plastic. The product is white or light yellow loose particles or powder which is odorless, odorless and non-toxic. After chlorination of PVC resin, the irregularity of molecular bonds increases, the polarity increases, the solubility of the resin increases, and the chemical stability increases, thereby improving the heat resistance, acid resistance, alkali, salt, oxidizing agent, etc. corrosion. The mechanical properties of the heat distortion temperature have been improved. The chlorine content has been increased from 56.7% to 63-69%, the Vicat softening temperature has been increased from 72-82 ℃, (increased to 90-125 ℃), and the maximum service temperature can reach 110 ℃ Long-term use temperature is 95 ℃. Among them, CORZAN CPVC performance index is better. Therefore, CPVC is a new engineering plastic with broad application prospects.
The tube uses polyvinyl chloride resin as a carrier, which has excellent characteristics such as accurate temperature sensing, timely melting, and effective absorption of additives when weakening the attraction between the resin molecular chains. At the same time, the world famous calcium and zinc composite heat stabilizer is used. The resin can trap, suppress, absorb and neutralize the hydrogen chloride during the high temperature and melting process, and perform a double bond addition reaction with the polyene structure to replace the active and unstable chlorine atoms in the molecule. So as to effectively and scientifically control the catalytic degradation and oxidative decomposition of the resin in the molten state.
It is a semi-crystalline material. It is harder than PE and has a higher melting point. Since the PP temperature of the homopolymer type is very brittle when it is higher than 0 ° C, many commercial PP materials are random copolymers added with 1 to 4% ethylene or clamp copolymers with a higher ratio of ethylene content. Copolymer PP materials have lower heat distortion temperature (100 ℃), low transparency, low gloss, low rigidity, but have stronger impact strength. The strength of PP increases with increasing ethylene content. The Vicat softening temperature of PP is 150 ° C. Due to the high crystallinity, this material has good surface stiffness and scratch resistance. PP does not have the problem of environmental stress cracking. Generally, PP is modified by adding glass fiber, metal additives or thermoplastic rubber. The flow rate MPP of PP ranges from 1 to 40. PP materials with low MFR have better impact resistance but lower ductility. For the same MFR material, the strength of the copolymer type is higher than that of the homopolymer type. Due to crystallization, the shrinkage of PP is quite high, generally 1.8 to 2.5%. And the direction uniformity of shrinkage is much better than PE-HD and other materials. Adding 30% glass additives can reduce the shrinkage to 0.7%. Both homopolymer and copolymer PP materials have excellent moisture absorption resistance, acid and alkali corrosion resistance, and solubility resistance. However, it is not resistant to aromatic hydrocarbon (such as benzene) solvents, chlorinated hydrocarbon (carbon tetrachloride) solvents, etc. PP, like PE, still has oxidation resistance at high temperatures.
Polypropylene (PP) is a lighter type of common plastics. It has excellent electrical properties and can be used as a damp-heat-resistant high-frequency insulating material. PP is a crystalline polymer, which exhibits a large shrinkage rate (1.0% -1.5%) due to a large specific volume change and a high degree of molecular orientation when the melt condenses. In the molten state of PP, the effect of increasing the temperature to reduce its viscosity is not great. Therefore, in the molding process, the injection pressure and shear rate should be increased to improve the molding quality of the product.
The full name is Polyethylene, which is the most simple polymer organic compound. The most widely used polymer material in the world today is made of ethylene. It is divided into high-density polyethylene, medium-density polyethylene and low-density polymer according to the density. Ethylene. Low-density polyethylene is softer and more often uses high-pressure polymerization; high-density polyethylene has the characteristics of high rigidity, hardness and mechanical strength, and more low-pressure polymerization. High-density polyethylene can be used as containers, pipes, or high-frequency electrical insulation materials for radar and television. Low density (high pressure) polyethylene is often used in large quantities. Polyethylene is waxy, with a wax-like smoothness. When not dyed, low-density polyethylene is transparent, while high-density polyethylene is opaque. -CH2- unit connected by a high polymer chain. The performance of polyethylene depends on its polymerization method; high-density polyethylene (HDPE) is formed by Ziegler-Natta polymerization under medium-pressure (15-30 atm) organic compound catalytic conditions. Under this condition, the polymerized polyethylene molecules are linear, and the molecular chain is very long, with a molecular weight of up to hundreds of thousands. If it is under high pressure (100-300MPa), high temperature (190–210 C), peroxide-catalyzed radical polymerization, low density polyethylene (LDPE) is produced, which is branched structure.
Polyethylene is insoluble in water and has very low water absorption. Even for some chemical solvents, such as toluene and acetic acid, it only dissolves slightly at temperatures above 70 ℃. However, particulate polyethylene can be melted or solidified with the change of temperature between 15 ℃ and 40 ℃. When the temperature increases, it melts and absorbs heat; when the temperature decreases, it solidifies and releases heat. Because of its small water absorption, it is not easy to be damp, and has insulating properties, so it is a very good building material.
Polybutene was developed and applied in the early 1970s, and its material characteristics determined that the technology and equipment requirements for the production of profiles are relatively high, and the investment in fixed assets is large. The general small-scale manufacturers do not have the technical conditions and financial capabilities for production.
PVDF Polyvinylidene fluoride
The appearance is translucent or white powder or particles, the molecular chains are closely arranged, and there are strong hydrogen bonds, the oxygen index is 46%, non-combustible, the crystallinity is 65% ~ 78%, the density is 1.17 ~ 1.79g / cm3 The melting point is 172 ℃, the heat distortion temperature is 112 ~ 145 ℃, and the long-term use temperature is -40 ~ 150 ℃.
PVDF resin king means a vinylidene fluoride homopolymer or a copolymer of vinylidene fluoride and other small amount of fluorine-containing vinyl monomers. PVDF resin has the characteristics of fluorine resin and general-purpose resin, in addition to having good chemical resistance and resistance In addition to high temperature resistance, oxidation resistance, weather resistance, and radiation resistance, it also has special properties such as piezoelectricity, dielectricity, and thermoelectricity. It is currently the second largest product in the production of fluoroplastics. The production capacity exceeds 43,000 tons. PVDF applications are mainly concentrated in the three major fields of petrochemicals, electrical and electronic and fluorocarbon coatings. Due to the good chemical resistance, processability, fatigue resistance and creep resistance of PVDF, it is the whole or lined pumps and valves of the petrochemical equipment fluid treatment system , One of the best materials for pipes, pipe fittings, storage tanks and heat exchangers. Its good chemical stability and electrical insulation properties make the equipment to meet the requirements of TOCS and flame retardancy, and are widely used in the storage and transportation of high-purity chemicals in the semiconductor industry. In recent years, porous membranes made of PVDF resin, Adhesives, separators, etc. are used in lithium secondary batteries. At present, this application has become one of the fastest growing markets for PVDF demand. PVDF is one of the most important raw materials for fluorocarbon coatings. The fluorocarbon coatings prepared from it have been developed to the sixth generation. Due to the super weather resistance of PVDF resin, it can be used outdoors for a long time without maintenance. Widely used in power stations, airports, highways, high-rise buildings, etc. In addition, PVDF resin can also be blended and modified with other resins, such as PVDF and ABS resin to obtain composite materials, which have been widely used in construction, automobile decoration, home appliance shells, etc.
PVC material is a kind of plastic decoration material. PVC is the abbreviation of polyvinyl chloride material, which is made of polyvinyl chloride resin as the main raw material, adding appropriate amount of anti-aging agent, modifier, etc., through mixing, calendering, vacuum suction and other processes.
PVC material has the characteristics of light weight, heat insulation, heat preservation, moisture proof, flame retardant, and easy construction. It has many specifications, colors and patterns, and is very decorative. It can be used in the decoration of indoor walls and ceilings. It is one of the most widely used decorative materials among plastic materials.
The advantages of PVC gussets are as follows:
1. Light weight, heat insulation, heat preservation, moisture proof, flame retardant, acid and alkali resistance, corrosion resistance.
2. Good stability, dielectric, durability, anti-aging, easy welding and bonding.
3. The bending strength and impact toughness are strong, and the elongation at break is high.
4. Through kneading, kneading, tablet pulling, pelletizing, extrusion or die casting and other processes, it is extremely easy to process and shape, and can meet the needs of various profile specifications.
5. The surface is smooth, the color is bright, the decoration is very rich, and the decorative application is wide.
6. The construction process is simple and the installation is more convenient.
The PE pipe is made of polyethylene material, and the PE pipe is suitable for concealed design, and the exposed material is easily aging.
In addition to the advantages of general plastic light weight, good strength, corrosion resistance, non-scaling, and long service life, PP-R pipe has the following main features:
(1) Non-toxic, hygienic and green building materials. PP-R raw material belongs to polyolefin, its molecule is composed of carbon and hydrogen elements, non-toxic, and has excellent sanitary performance;
(2) Heat-resistant and heat-insulating, which are energy-saving products. The PP-R pipe Vicat softening temperature is 131.3 ℃, the maximum operating temperature is 95 ℃, and the long-term (50 years) operating temperature can be as high as 70 ℃. The thermal conductivity of this product is 0.24W / m ℃, which is only 1 / 200, used for hot water pipeline insulation and energy saving effect is excellent;
(3) Convenient and reliable installation, using hot-melt homogenous connection, a joint can be completed in a few seconds, and high-quality metal insert pipe fittings are used to connect metal pipes and water heaters, which is safe and reliable.
PP-R cold and hot water pipe application field
Hot and cold water systems in buildings, including central heating systems;
The heating system in the building, including floor, siding and radiant heating systems;
Pure drinking water supply system;
Central (centralized) air conditioning system;
Agriculture, garden irrigation system;
Rainwater pipe network; swimming pool pipe network;
Pipe network of solar facilities;
PPR is generally used for small pipe diameters.
PB pipe is a polymer material of polybutene. At present, PB pipe has been widely used in developed countries such as Europe and the United States, and it has replaced copper pipe as the material of choice for hot water supply pipes.
The main raw material of the PEX pipe is HDPE, as well as initiators, cross-linking agents, catalysts and other additives. If there are special requirements, other modifiers can be added.
The PEX tube is manufactured using the world's advanced one-step method (MONSOIL method) technology, using common polyethylene raw materials and silane grafting material to form a chemical covalent bond between polymer macromolecular chains to replace the original van der Waals force, thereby forming a three-dimensional Cross-linked polyethylene with cross-linked network structure, the degree of cross-linking can reach 60% ~ 89%, making it have excellent physical and chemical properties.
ABS is a ternary copolymer based on styrene-butadiene-acrylonitrile, which has high impact toughness and good mechanical strength, heat resistance, oil resistance, etc.
The household wiring is made of PVC pipes, and it should be standard fire-resistant PVC pipes. There are also some re-layed sewage pipes that use PVC pipes. The commonly used PPR is used for waterway reconstruction. PPR is more suitable for water.
The essential difference is the different raw materials. ppr is random copolymer polypropylene pvc is polyvinyl chloride pvc water supply and drainage can be used ppr is mainly water supply (used as drainage cost is too high) In fact, pvc is not a toxic medical infusion tube and many plastic packaging are pvc The is used as a building only with the addition of modifiers Furthermore, ppr can be hot melted pvc can not.
PPR is made of copolymer polypropylene material, PVC is made of polyvinyl chloride material, the former has high production cost, and the hygienic level is also better than PVC, and it can take hot water below 75 ℃. The disadvantage is that it is easier to deform. PVC is Because the production cost is low, it is widely used for farmland irrigation. The disadvantage is that it can only take cold water.
The low temperature embrittlement temperature of PE water supply pipe is very low, and it can be used in the range of -40 ℃ to 60 ℃. Pipeline brittleness will not occur during winter installation.
Polyethylene is an inert material that can withstand the erosion of various chemical media without corrosion protection. The chemical substances in the soil will not cause any degradation of the pipeline, and will not cause rot, rust and corrosion.
PE water supply pipe break elongation exceeds 800%, local vibration will not cause vibration of all pipes, and strong shock resistance. The winding of polyethylene makes PE water supply pipe coilable, reducing a large number of connecting pipe fittings and bypassing obstacles during construction To reduce the difficulty of construction.
Due to the high crystallinity of HDPE, the strength and hardness increase accordingly. The welding is tight and can withstand the internal pressure. It is generally used in water supply and burning pressure pipes.
It is hygienic and non-toxic, does not breed bacteria in the pipe, will not cause secondary pollution of water quality, and completely solves the defects of pipeline pollution of water sources.
The inner wall of the PE water supply pipe is smooth, the friction coefficient is small, the fluid resistance is small, the head loss is small, and there is no scaling. The pressure loss of the pipeline and the energy consumption of water delivery are reduced, and the economic advantages are obvious.
PE water supply pipe adopts hot-melt connection and electric fusion connection. The interface strength is higher than the strength of the pipe body, which can effectively resist the hoop force and axial force generated by the internal pressure. The sealing performance is good, and there is no need to worry about the pipe leakage caused by the interface distortion.If you want to know more about it please do not hesitate to contact me. WhatsApp:+86-15966835076