Budweiser Canned 500ml ,Cheerful Corona Extra On A Road Trip,Enjoy Corona Extra With Good Times,Chilled Corona For Summer Evenings Yanbian Baichuan Import and Export Trade Co., LTD , https://www.baichuanbeer.com
There are four main types of greenhouse films commonly used in China: polyvinyl chloride (PVC), polyethylene (PE), ethylene-vinyl acetate (EVA) copolymer film, and light-modulating agricultural films. Each has its own unique characteristics, advantages, and limitations, which affect their performance and suitability for different agricultural applications.
PVC films are known for their good insulation, light transmission, and weather resistance. They are soft and easy to shape, making them suitable for greenhouses, sheds, and other structures. However, they have a higher specific gravity (1.3 g/cm³), which reduces the coverage area per unit weight compared to PE films, leading to higher costs. At low temperatures, PVC becomes hard and brittle, while at high temperatures, it may soften or deform. Over time, additives in the film may leach out, causing the surface to collect dust and reduce light transmission. Additionally, burning PVC films releases chlorine gas, making disposal environmentally challenging.
PVC films come in several varieties. The standard PVC film lacks anti-aging agents and lasts only 4–6 months, suitable for one growing season. The anti-aging PVC film includes UV stabilizers and lasts 8–10 months, widely used in greenhouses. The non-drip anti-aging PVC film (double anti-shedding film) maintains non-drip properties for 4–6 months and has a service life of up to 12–18 months, making it ideal for energy-efficient solar greenhouses. Lastly, the weather-resistant dripless dust film improves light transmission and is beneficial for winter and spring cultivation.
Polyethylene (PE) films are lighter (specific gravity 0.92 g/cm³), softer, and easier to process. They are non-toxic and widely used in agriculture. However, they have poor weather resistance and heat retention unless modified with additives like UV stabilizers, anti-drip agents, and heat-insulating materials. Common PE films include the standard type, which lasts 4–6 months, and the long-lasting anti-aging PE film, which can last 12–18 months and support 2–3 growing seasons. The non-drip anti-aging PE film combines multiple benefits and is widely used in various greenhouse structures. Insulation PE films help retain heat, increasing greenhouse temperatures by 1–2°C, especially in colder regions. Multi-functional composite PE films offer additional features such as UV blocking and disease inhibition, extending their lifespan to 12–18 months.
Ethylene-vinyl acetate (EVA) films are a newer material that offers better light transmission, heat retention, and weather resistance than both PVC and PE. EVA films can increase crop yields by about 10% and last over two years without deformation. After use, they are easily recyclable, reducing environmental impact.
Light-modulating films, often made from PE resin with rare earth additives, selectively transmit light, enhancing solar energy utilization. These films improve warming, heat retention, and crop growth, promoting early maturity, higher yield, and improved nutrient content. Some special versions, like purple films for leafy vegetables, are designed to reduce glare, increase temperature, and enhance quality and yield. They also contain UV-absorbing components, extending the film’s lifespan.
Overall, each type of greenhouse film has its own strengths and weaknesses, and the choice depends on factors such as climate, crop type, and economic considerations. Farmers should select the most appropriate film based on their specific needs and conditions.