Description
Polyvinyl chloride, referred to as PVC, is a polymerization of vinyl chloride monomer (VCM) with initiators such as peroxides and azo compounds, or under the action of light and heat according to the free radical polymerization reaction mechanism. things. Vinyl chloride homopolymer and vinyl chloride copolymer are collectively called vinyl chloride resin.
PVC is a white powder with an amorphous structure. It has a small degree of branching and a relative density of about 1.4. It has a glass transition temperature of 77~90°C and begins to decompose around 170°C. It has poor stability to light and heat. When exposed to sunlight, it will decompose to produce hydrogen chloride, which will further autocatalytically decompose, causing discoloration and rapid decline in physical and mechanical properties. In practical applications, stabilizers must be added to improve the stability against heat and light.
Features
- It has flame retardancy (flame retardant value is above 40), high chemical resistance (resistant to concentrated hydrochloric acid, 90% sulfuric acid, 60% nitric acid and 20% sodium hydroxide), mechanical strength and electrical resistance with good insulation.
- Polyvinyl chloride has poor stability to light and heat. The softening point is 80°C and begins to decompose at 130°C. Without heating the stabilizer, PVC begins to decompose at 100°C and decomposes faster above 130°C.
- It has stable physical and chemical properties, is insoluble in water, alcohol, and gasoline, and has low leakage of gas and water vapor, it can withstand any concentration of hydrochloric acid, sulfuric acid below 90%, nitric acid below 50-60%, and nitric acid below 20% at normal temperature. The caustic soda solution has certain resistance to chemical corrosion, it is quite stable to salts, but can be dissolved in organic solvents such as ethers, ketones, chlorinated aliphatic hydrocarbons and aromatic hydrocarbons.
- It has good printability, good light transmittance, good processability, non-toxic, waterproof, environmentally friendly, easy to clean and rich in color. This gives it a wide range of applications, especially in the printing and packaging fields.
Applications
- Construction field: In the construction field, transparent thin film PVC membrane is widely used in waterproofing, heat preservation and heat insulation of roofs and walls. Its high transparency, water resistance and durability make it an ideal building material. By using clear thin film PVC membrane, architects and designers can create unique and feature rich building structures.
- Agricultural field: In the agricultural field, transparent thin film PVC film is widely used in the protection of greenhouses and farmland. Its high transparency allows sunlight to pass through, aiding photosynthesis in plants. At the same time, PVC film can also provide insulation and moisturizing functions, helping to improve the yield and quality of crops. In addition, PVC film can also prevent the invasion of pests and diseases and reduce the use of pesticides.
- Packaging field: Transparent plastic PVC film is widely used because of its high transparency and good moisture-proof performance. It allows consumers to clearly see the product inside the package and improves purchase intention. At the same time, PVC membrane can also protect products from moisture and pollution. In addition, PVC film can also provide certain shock-proof and impact-proof functions to ensure the safety of products during transportation.
- Printing field: The high transparency and smooth surface of plastic PVC film make it an ideal printing substrate. It is suitable for various printing processes, such as screen printing, gravure printing and flexographic printing, etc. PVC film can provide high-quality printing effects and has good durability and waterproof properties. Therefore, it has a wide range of applications in advertising, labels, packaging and other fields.
- Other fields, in addition to the above fields, transparent plastic PVC films are also used in many other fields. For example, in the medical field, PVC films can be used to make medical supplies, such as gloves, isolation gowns, and pharmaceutical packaging. In the field of environmental protection, PVC film can be used to make garbage bags and recycling bags, helping to reduce environmental pollution. In addition, PVC film can also be used to make packaging for optical devices and electronic components to provide protection and moisture-proof functions.
Structure
