The main purpose of the greenhouse structure is to fix the covering material. Therefore, the covering material and its characteristics are one of the most important parts of the entire greenhouse. The ideal covering material should have a large light transmittance, be able to prevent heat loss to the outside, be strong and durable, be as easy to install as possible and be cheap.
Glass–Advantages: Excellent light transmittance-about 90%; better thermal resistance and UV protection, wear resistance; low thermal expansion and contraction coefficient; easy to obtain. Its disadvantages are: low impact resistance (except for tempered glass); high price (material + sealing); heavy weight; easy to break, and difficult to clean after breaking.
Polyethylene (P.E.) film–In countries with moderate climates, polyethylene is the most common greenhouse covering material. The reason for its widespread use is, first of all, its low price; secondly, it can be used in a large number of simple structure greenhouses. The life of P.E. film is very short, and it can last about 7 to 9 months depending on the time when it starts to cover the shed. The biggest disadvantage of P.E. film is that when there is wind, PE film is not easy to fix, and it lacks reliable safety when laid on the roof. Multi-layer woven polyethylene film P.E. This material is more difficult to make and does not stretch as well as ordinary P.E. film. On the other hand, it is strong enough to withstand strong winds and even light flapping. The material is produced in a width of 2 meters, so in order to meet the appropriate width required for the roof, it must be welded. Generally, the warranty period of this material is 3 years.
Reinforced polyvinyl chloride film – polyvinyl chloride (P.V.C) as a basic material has excellent properties similar to glass and other good materials. Ordinary clean P.V.C film has a light transmittance of about 85%, but its performance is poor in terms of expansion and construction and installation performance. For this reason, the film becomes loose in warm climates and may be blown away by wind.
Rigid plastic covered fiberglass reinforced plastic (FRP) board – has been used for many years. Especially in the United States, there are various products on the market with different service life guarantees. Boards with special protective layers can even last up to 20 years, but the price is also very high. When new, the light transmittance of FRP boards is very close to that of glass. But after a few years of use, the fibers begin to separate from the polyester, the light transmittance decreases, and the board begins to yellow.
Corrugated PVC sheet–also one of the hard plastics used to cover greenhouses in the past. Its biggest problem is that it has poor high temperature resistance.
Polycarbonate hollow sheet–polycarbonate is one of the most advanced polymers currently used in plastic applications. Polycarbonate has the characteristics of combining various properties: strength, light transmittance, elasticity, light weight, transparency, wide temperature adaptability, etc. The board is manufactured using an improved co-extrusion molding technology, which can incorporate a UV protection layer into the product. The protective layer does not peel, wrinkle, crack or wear. The board can also maintain its light transmittance at high temperatures. Its visible light transmittance is 89%; it can completely block harmful ultraviolet radiation; it has a high absorption rate for far infrared; it is light in weight; therefore, it is easy to install. There is a separate guarantee for hail damage. There is a 10-year guarantee on quality.
Company Name: Baoding Xinhai Plastic Sheet Co.,ltd
Contact Person: Sale Manager
Email: admin@cnxhpcsheet.com
Phone/Wechat/Whatsapp: +8619932587617
Country: China
Website: https://www.xhplasticsheet.com/
Post time: Jul-31-2024