PVC: It has stable physical and chemical properties, insoluble in water, alcohol, gasoline, and low leakage of gas and water vapor; It can resist any concentration of hydrochloric acid, less than 90% sulfuric acid, 50-60% nitric acid and less than 20% caustic soda solution at room temperature, and has certain chemical corrosion resistance; It is quite stable to salts, but can be dissolved in organic solvents such as ethers, ketones, chlorinated aliphatic hydrocarbons and aromatic hydrocarbons.
PP: Polypropylene is a non-toxic, odorless, tasteless milky white highly crystalline polymer with a density of only 0. 90–“0. At 91g/cm3, it is one of the lightest varieties of all plastics at present. It is particularly stable to water and has a water absorption rate of only 0 in water. 01%, with a molecular weight of about 80,000 to 150,000.Good formability, but due to the large shrinkage rate (1% ~ 2.5%), thick-walled products are easy to dent, for some parts with high dimensional accuracy, it is difficult to meet the requirements, and the surface gloss of the products is good.
The characteristics are different
PVC: PVC has the advantages of flame retardant (flame retardant value of more than 40), high chemical resistance (resistance to concentrated hydrochloric acid, sulfuric acid with a concentration of 90%, nitric acid with a concentration of 60% and sodium hydroxide with a concentration of 20%), mechanical strength and good electrical insulation.
PP: non-toxic, odorless, low density, strength, stiffness, hardness and heat resistance are better than low-pressure polyethylene, can be used at about 100 °C. It has good dielectric properties and high-frequency insulation, and is not affected by humidity, but it becomes brittle at low temperature, is not wear-resistant, and is easy to age. It is suitable for making general mechanical parts, corrosion-resistant parts and insulating parts. Common organic solvents such as acids and alkalis have almost no effect on it and can be used for the production of tableware.
The application scenarios are different
PVC: Stabilizers, lubricants and fillers are added to PVC, and after mixing, the extruder can be used to extrude hard pipes, special-shaped pipes and corrugated pipes of various calibers for sewer pipes, drinking water pipes, wire casings or stair handrails.
The calendered sheets are superimposed and hot-pressed to make rigid sheets of various thicknesses. The sheets can be cut into the desired shape and then welded with hot air using PVC electrodes into a variety of chemically resistant tanks, air ducts and containers.
The extruder can be extruded into hoses, cables, wires, etc.; Using injection molding machines with various molds, it can be made into plastic sandals, shoe soles, slippers, toys, auto parts, etc.
PP: household appliances, plastic pipes, high permeability materials, After adding related materials, the extruder can be used to extrude various calibers of hard pipes, special-shaped pipes, spray towers, activated carbon boxes, etcetc.
Polypropylene has good mechanical properties, and can be directly manufactured or modified to manufacture parts and components of various mechanical equipment, such as manufacturing industrial pipelines, agricultural water pipes, motor fans, infrastructure templates, etc. Modified polypropylene can be molded into bumpers, scuff strips, car steering wheels, dashboards and interior decorations, etc., which greatly reduce the weight of the body and achieve the purpose of saving energy.
Modified polypropylene can be used to make insulating shells of household appliances and washing machine liners, and is widely used in insulating materials for wires, cables and other electrical appliances. The polypropylene composite material made of homopolymer polypropylene 60~80 parts by weight, ethylene-vinyl alcohol copolymer 20~40 parts, compatibilizer (reactant of polypropylene maleic anhydride graft and ethylene-vinyl alcohol copolymer) 1~10 parts, mixed at 170 °C ~ 190 °C has high toughness, its impact strength is as high as 210J / m, has high gas barrier properties, and the permeable vapor rate is close to 2000g · μm / (m2 · 24h). In the preparation of barrier films, the traditional film-making process can be used for production, the process is relatively simple, and the production cost is low.
